CoChat
Sign Up
Cited by 31Diet and metabolism studiesDietary Effects on HealthDiabetes Management and Research

Benefits of low carbohydrate diets: a settled question or still controversial?

Open access
Landry, Matthew J., Crimarco, Anthony, Gardner, Christopher D.·2021·Current Obesity Reports
DOI 10.1007/s13679-021-00451-zPMC PMC9621749
Open this paper in CoChat — free account

Abstract

Purpose of Review The purpose of this review was to provide an update on the available data on the benefits of low-carbohydrate (low-carb) diets for weight management and type 2 diabetes (T2DM) and determine if low-carb diets were a settled question or still controversial. Recent Findings Most of the recent published literature in this area consists of reviews of past trials, with a relatively smaller number of recent trials. Low-carb is most commonly compared to low-fat, with problematically inconsistent definitions of both. There are numerous challenges in trying to draw clear conclusions about efficacy and effectiveness. Short-term vs. long-term effects can differ, which is likely impacted by adherence. Adherence is very different between metabolic chamber or feeding studies vs. free-living. Body weight alone is a crude measure that fails to capture potentially important differences in lean-mass, fat-mass, and body water. Benefits for glycemic control need to be balanced with impacts on non-glycemic outcomes such as LDL-cholesterol, the microbiome, and inflammation. It is important to differentiate between low-carb and very-low carbohydrate diets (VLCD). To date no large-scale long-term clinical trials have been conducted testing whether low-carb diets can prevent T2DM. Summary Many issues regarding benefits and risks of low-carb diets remain controversial or unresolved, particularly for VLCD. Some of the recent, better studies highlighted in this review suggest strategies for resolving these controversies.

AI snapshot

Written from the paper’s full text.

TL;DR

This narrative review concludes that low-carbohydrate diets are not clearly superior to other diets for long-term weight loss, but may improve glycemic control and reduce diabetes medications in type 2 diabetes. Many questions remain controversial or unresolved, especially for very-low-carbohydrate/ketogenic diets.

Key findings

  • For long-term weight loss, a summary of 62 randomized trials found greater weight loss for low-carbohydrate diets in 31 studies, but among studies lasting 12 months or longer only 4 out of 18 reported greater weight loss for low-carbohydrate diets; an umbrella review found little or no difference among higher-quality studies.
  • In two metabolic ward studies, very-low-carbohydrate diets increased energy expenditure by 151 kcal/d and 153 kcal/d, but in one study the plant-based low-fat phase led to less daily energy intake (689 ± 73 kcal/d), and early weight loss was largely fat-free mass/water.
  • For diabetes, a 2018 systematic review of 33 RCTs found low-carbohydrate diets may clinically importantly reduce HbA1c versus low-fat diets (low certainty), while the 2-year non-randomized Virta trial reported 53.5% diabetes reversal and reduced medications; a 2-year RCT in 115 adults found comparable weight and HbA1c reductions but greater medication reductions and diurnal glucose stability with low-carbohydrate diets.
  • Definitions remain inconsistent (low-carbohydrate ranging from 5% to 40% of energy; very-low-carbohydrate generally <50 g/day), and no large-scale long-term trial has tested whether low-carbohydrate diets prevent type 2 diabetes.

Methods

  • Narrative review of recent literature on low-carbohydrate and very-low-carbohydrate diets for obesity/weight management and type 2 diabetes, focused on the last 5 years and trials published between 2000 and 2021.
  • The evidence base consisted mainly of recent reviews, meta-analyses, and systematic reviews, with a relatively smaller number of recent trials; no primary data were collected.
  • Main analysis was narrative synthesis; no formal meta-analysis or systematic search protocol is reported.

Limitations

  • The paper states that included studies have inconsistent definitions of low-carbohydrate and very-low-carbohydrate diets, poor or inadequately assessed adherence, short durations, and comparison diets that were sometimes lower quality or had no dietary intervention.
  • The paper states that long-term safety, adherence, and efficacy data are lacking, especially for very-low-carbohydrate diets, and that no large-scale long-term trial has tested type 2 diabetes prevention.
  • Evident from the text: as a narrative review, it does not use a systematic search/selection strategy or quantitative synthesis, so conclusions depend on the selected literature.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1007/s13679-021-00451-z

Cites

127 of 127 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 130 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Recent publications on low-carbohydrate or very-low-carbohydrate diets are more likely to be review articles than randomized controlled trials.

    “Yet, recent publications on low-carbohydrate or very-low-carbohydrate diets results are more likely to be review articles than randomized controlled trials (RCTs) (Table 1).”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    Low-carbohydrate diets, as studied in general, are neither superior nor inferior to low-fat or other reasonable alternative dietary approaches (e.g., Mediterranean, healthy low-fat diet).

    “Low-carbohydrate diets, as has been studied in general, are neither superior nor inferior to low-fat or other dietary approaches that offer a reasonable alternative (e.g., Mediterranean, healthy low-fat diet).”
    Quote in the paperSubstantial claim
  • Findingnone given

    There is an absence of evidence to determine whether low- or very-low carbohydrate diets could prevent the onset of incident diabetes.

    “there is an absence of evidence to determine whether low- or very-low carbohydrate diets could prevent the onset of incident diabetes.”
    Quote in the paperSubstantial claim
  • Findingreasoning

    As studied, most dietary approaches in general have been negligibly to nominally effective.

    “As studied, most dietary approaches in general have been negligibly to nominally effective.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: If any of the current dietary approaches was strikingly more effective than others, the entire field would have shifted to adopt and promote that approach.
  • Interpretationnone given

    Many issues regarding benefits and risks of low-carb diets remain controversial or unresolved, particularly for VLCD.

    “Many issues regarding benefits and risks of low-carb diets remain controversial or unresolved, particularly for VLCD.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 26
  • May combine two claims. 40

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    Most of the recent published literature in this area consists of reviews of past trials, with a relatively smaller number of recent trials.

    “Most of the recent published literature in this area consists of reviews of past trials, with a relatively smaller number of recent trials.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Glycemic load is associated with adverse long-term health effects, and consumption of easily digestible carbohydrates such as sugar promotes obesity.

    “Glycemic load (the product of glycemic index and carbohydrate content) is associated with adverse long-term health effects, and consumption of easily digestible carbohydrates (e.g., sugar) promotes obesity [4•, 5, 6].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [4•]

      Not checked in the free run.

    • cites [5] Giugliano D, Maiorino MI, Bellastella G, Esposito K. More sugar? No, thank you! The elusive nature of low carbohydrate diets. Endocrine. 2018;61(3):383–7. source

      Not checked in the free run.

    • cites [6] Mooradian AD. The merits and the pitfalls of low carbohydrate diet: a concise review. J Nutr Health Aging. 2020;24(7):805–8. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Emerging research has examined associations between low-carbohydrate and very-low-carbohydrate diets and cancer, polycystic ovary syndrome, cardiovascular disease risk parameters, nonalcoholic fatty liver disease, and neurological diseases, with some evidence of benefit but a need for further research.

    “Emerging research has examined the association between use of low-carbohydrate and very-low-carbohydrate diets in cancer [11–13], polycystic ovary syndrome[14], cardiovascular disease risk parameters [15••, 16], nonalcoholic fatty liver disease [17–19], and neurological diseases [20, 21] with some evidence of benefit, but further research is needed.”
    Quote in the paperNot a substantial claim0 of 5 sources checked
    • cites [11] Klement RJ. The emerging role of ketogenic diets in cancer treatment. Curr Opin Clin Nutr Metab Care. 2019;22(2):129–34. source

      Not checked in the free run.

    • cites [12] Weber DD, Aminzadeh-Gohari S, Tulipan J, Catalano L, Feichtinger RG, Kofler B. Ketogenic diet in the treatment of cancer–where do we stand? Molecular metabolism. 2020;33:102–21. source

      Not checked in the free run.

    • cites [13] Oliveira CL, Mattingly S, Schirrmacher R, Sawyer MB, Fine EJ, Prado CM. A nutritional perspective of ketogenic diet in cancer: a narrative review. J Acad Nutr Diet. 2018;118(4):668–88. source

      Not checked in the free run.

    • cites [14] Paoli A, Mancin L, Giacona MC, Bianco A, Caprio M. Effects of a ketogenic diet in overweight women with polycystic ovary syndrome. J Transl Med. 2020;18(1):1–11. source

      Not checked in the free run.

    • cites [15••, 16]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    Short-term versus long-term effects of low-carb diets can differ, and this difference is likely impacted by adherence.

    “Short-term vs. long-term effects can differ, which is likely impacted by adherence.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Adherence is very different between metabolic chamber or feeding studies and free-living conditions.

  • Classified as probably not a substantial claim.

    Premisecitation

    One rationale for low-carbohydrate or very-low-carbohydrate diets stems from the idea that excessive carbohydrate intake may promote weight gain through the stimulation of insulin release and hunger.

    “One rationale for a low-carbohydrate or very-low-carbohydrate diets stems from the idea that excessive carbohydrate intake may promote weight gain through the stimulation of insulin release and hunger [4•].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [4•]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Very-low-carbohydrate diets generally contain less than 50 g and often as few as 20 g of total carbohydrates per day, which is less than 10% of calories on a 2000 kcal/day diet.

    “Very-low-carbohydrate diets, also referred to as ketogenic diets, are the most restrictive, generally containing < 50g and often as few as 20g of total carbohydrates per day (<10% of calories, on a 2000 kcal/day diet) [30].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [30] Evert AB, Dennison M, Gardner CD, Garvey WT, Lau KHK, MacLeod J, et al. Nutrition therapy for adults with diabetes or prediabetes: a consensus report. Diabetes Care. 2019;42(5):731–54. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    Low-carb is most commonly compared to low-fat, with problematically inconsistent definitions of both.

    “Low-carb is most commonly compared to low-fat, with problematically inconsistent definitions of both.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The Mediterranean diet is a moderately low-carbohydrate diet pattern, in the range of 35-40% energy from carbohydrates.

    “As a consequence, the Mediterranean diet is a moderately low-carbohydrate diet pattern, in the range of 35–40% energy from carbohydrates [29].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [29] Davis C, Bryan J, Hodgson J, Murphy K. Definition of the Mediterranean diet; a literature review. Nutrients. 2015;7(11):9139–53. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    To achieve ketosis, very-low-carbohydrate diets, and to some extent low-carbohydrate diets, require elimination or severe restriction of legumes, fruits, starchy vegetables, and grains, despite the established general health benefits of these foods.

    “To achieve ketosis, very-low-carbohydrate diets, and to some extent low-carbohydrate diets, require the elimination or severe restriction of legumes, fruits, starchy vegetables, and grains (including whole grains), despite the established general health benefits of these foods and food groups [30, 32, 33].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [30] Evert AB, Dennison M, Gardner CD, Garvey WT, Lau KHK, MacLeod J, et al. Nutrition therapy for adults with diabetes or prediabetes: a consensus report. Diabetes Care. 2019;42(5):731–54. source

      Not checked in the free run.

    • cites [32] Dietary Guidelines Advisory Committee. Scientific Report of the 2020 Dietary Guidelines Advisory Committee: Advisory Report to the Secretary of Agriculture and the Secretary of Health and Human Services. Washington, DC: U.S. Department of Agriculture, Agricultural Research Service; 2020.

      Not checked in the free run.

    • cites [33] Arnett DK, Blumenthal RS, Albert MA, Buroker AB, Goldberger ZD, Hahn EJ, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2019;74(10):e177–232. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    There is substantial variability in definitions of low-carbohydrate diets in the literature, from 5 up to 40% of energy intake or total daily grams of carbohydrate.

    “There is substantial variability in definitions of “low-carbohydrate” diets in the literature in terms of percentage from energy intake or total daily grams of carbohydrate, anywhere from 5 up to 40% [23, 24].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [23] Yamada S. Paradigm shifts in nutrition therapy for type 2 diabetes–nutrition therapy for diabetes. The Keio journal of medicine. 2017;66(3):33–43. source

      Not checked in the free run.

    • cites [24] Spritzler F. A low-carbohydrate, whole-foods approach to managing diabetes and prediabetes. Diabetes Spectr. 2012;25(4):238–43. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    To date no large-scale long-term clinical trials have been conducted testing whether low-carb diets can prevent T2DM.

    “To date no large-scale long-term clinical trials have been conducted testing whether low-carb diets can prevent T2DM.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    These dietary patterns and practices tend to be high in saturated fat consumption, which can increase plasma LDL-C and risk for premature cardiovascular disease.

    “These dietary patterns and practices tend to be high in saturated fat consumption which can increase plasma LDL-C and risk for premature cardiovascular disease [34, 35].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [34] O'Neill B, Raggi P. The ketogenic diet: pros and cons. Atherosclerosis. 2020;292:119–26. source

      Not checked in the free run.

    • cites [35] Yu E, Malik VS, Hu FB. Cardiovascular disease prevention by diet modification: JACC health promotion series. J Am Coll Cardiol. 2018;72(8):914–26. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In another study, energy expenditure was 153 kcal/d higher during the low-carbohydrate phase, but the plant-based diet led to less daily energy intake (689 ± 73 kcal/d) than the low-carbohydrate diet.

    “The EE was 153 kcal/d higher during the low-carbohydrate phase. However, the plant-based diet led to less daily energy intake (689 ± 73 kcal/d) than the low-carbohydrate diet.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [56••]

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Most clinical trials assessing low-carbohydrate diets versus low-fat or comparison diets are short in duration, less than 1 year, and/or involve significant design limitations.

    “Due to the fact that most clinical trials assessing low-carbohydrate diets versus low-fat diets, or comparison diets, are short in duration (< 1 year) and/or involve significant design limitations, it is not surprising that many of the meta-analyses and systematic reviews report little to no differences in long-term weight loss between diet types [7].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [7] Ludwig DS. The ketogenic diet: evidence for optimism but high-quality research needed. J Nutr. 2020;150(6):1354–9. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Evidence suggests that ketosis may provide a mechanism for appetite suppression and may decrease food consumption.

    “Individuals in ketosis may feel more full or satiated, as evidence suggests that ketosis may provide a mechanism for appetite suppression and resultingly may decrease food consumption [38, 39].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [38] Gibson AA, Seimon RV, Lee CM, Ayre J, Franklin J, Markovic T, et al. Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. Obes Rev. 2015;16(1):64–76. source

      Not checked in the free run.

    • cites [39] Deemer SE, Plaisance EP, Martins C. Impact of ketosis on appetite regulation—a review. Nutr Res. 2020;77:1–11. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Initiating a ketogenic diet may cause symptoms or side effects such as nausea, headache, and fatigability, which may lead people to discontinue the diet early.

    “However, they may also experience symptoms/side effects (nausea, headache, fatigability) from initiating a ketogenic diet, commonly referred to as the “keto flu” which may lead people to discontinue the diet early on [40].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [40] Bostock E, Kirkby KC, Taylor BV, Hawrelak JA. Consumer reports of “keto flu” associated with the ketogenic diet. Frontiers in nutrition. 2020;7:20. source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Early studies reported that low-carbohydrate diets resulted in greater weight loss, glycemic control, and improvements in cardiometabolic risk factors, primarily decreases in triglycerides and increases in HDL-C cholesterol.

    “Early studies reported that low-carbohydrate diets resulted in greater weight loss, glycemic control, and improvements in cardiometabolic risk factors (primarily decreases in triglycerides and increases in HDL-C cholesterol).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Ketogenic diets have been found to consistently lower triglycerides and raise HDL-C concentrations, both considered beneficial for cardiovascular health.

    “Ketogenic diets have also been found to consistently lower triglycerides and raise HDL-C concentrations, both of which are considered beneficial for cardiovascular health [15, 36, 37].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [15] Kirkpatrick CF, Bolick JP, Kris-Etherton PM, Sikand G, Aspry KE, Soffer DE, et al. Review of current evidence and clinical recommendations on the effects of low-carbohydrate and very-low-carbohydrate (including ketogenic) diets for the management of body weight and other cardiometabolic risk factors: a scientific statement from the National Lipid Association Nutrition and Lifestyle Task Force. J Clin Lipidol. 2019;13(5):689–711. e1. Comprehensive review of the current evidence base available from recent systematic reviews and meta-analyses on the effects of low-CHO and very-low-CHO diets on bo source

      Not checked in the free run.

    • cites [36] Rosenbaum M, Hall KD, Guo J, Ravussin E, Mayer LS, Reitman ML, et al. Glucose and lipid homeostasis and inflammation in humans following an isocaloric ketogenic diet. Obesity (Silver Spring). 2019;27(6):971–81. source

      Not checked in the free run.

    • cites [37] Hyde PN, Sapper TN, Crabtree CD, LaFountain RA, Bowling ML, Buga A et al. Dietary carbohydrate restriction improves metabolic syndrome independent of weight loss. JCI insight. 2019;4(12). source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Overall metabolic and physiological benefits have been reported for utilizing a low-carbohydrate approach to weight loss and management, including increased energy expenditure, reduced appetite, and better insulin control.

    “However, there are overall metabolic and physiological benefits that were reported for utilizing a low-carbohydrate approach to weight loss and management, including increased EE, reduced appetite, and better insulin control.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    An umbrella review indicated that lower quality studies reported overall superiority in weight loss for low-carbohydrate diets, but among higher quality studies there were little or no differences between diets.

    “An umbrella review (i.e., a meta-analysis of meta-analyses) indicated that lower quality studies did report overall superiority in weight loss for low-carbohydrate diets, but among the subset of higher quality studies, there were little or no differences between diets [60].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [60] Churuangsuk C, Kherouf M, Combet E, Lean M. Low-carbohydrate diets for overweight and obesity: a systematic review of the systematic reviews. Obes Rev. 2018;19(12):1700–18. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    For some individuals with certain chronic diseases or comorbidities, very-low-carbohydrate diets are discouraged or require evaluation and close medical monitoring.

    “For some individuals with certain chronic diseases (e.g., type 1 diabetes, chronic kidney disease, liver failure) or comorbidities, very-low-carbohydrate diets are discouraged or require evaluation and close medical monitoring from a disease specialist to assess contraindication [41•].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [41•]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Other analyses have reported greater energy expenditure from low-carbohydrate diets.

    “Other analyses have reported greater EE from low-carbohydrate diets [62, 63].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [62] Ebbeling CB, Bielak L, Lakin PR, Klein GL, Wong JM, Luoto PK, et al. Energy requirement is higher during weight-loss maintenance in adults consuming a low-compared with high-carbohydrate diet. J Nutr. 2020;150(8):2009–15. source

      Not checked in the free run.

    • cites [63] Ludwig DS, Greco KF, Ma C, Ebbeling CB. Testing the carbohydrate-insulin model of obesity in a 5-month feeding study: the perils of post-hoc participant exclusions. Eur J Clin Nutr. 2020;74(7):1109–12. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The 2014 AHA/ACC/TOS guidelines state that the level of certainty of evidence for low-carbohydrate approaches to weight loss is low.

    “After reviewing the evidence base for a comprehensive set of different weight loss diets, the 2014 guidelines from the American Heart Association (AHA), American College of Cardiology (ACC), and the Obesity Society (TOS) on the management of overweight and obesity in adults state that the level of certainty of evidence for low-carbohydrate approaches to weight loss is low [61].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [61] Jensen MD, Ryan DH, Apovian CM, Ard JD, Comuzzie AG, Donato KA, et al. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society. J Am Coll Cardiol. 2014;63(25 Part B):2985–3023. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Most reviews report that the majority of RCTs on low-carbohydrate versus low-fat diets indicate effective weight loss, glycemic control, and some improvements in metabolic risk factors in the short term, defined as 6 months or less.

    “Most of the reviews report the same general conclusions: the majority of RCTs on low-carbohydrate vs. low-fat diets indicate effective weight loss, glycemic control, and some improvements on metabolic risk factors in the short term (i.e., 6 months or less) [15••, 57–60].”
    Quote in the paperSubstantial claim0 of 5 sources checked
    • cites [15••]

      Not checked in the free run.

    • cites [57] Chawla S, Tessarolo Silva F, Amaral Medeiros S, Mekary RA, Radenkovic D. The effect of low-fat and low-carbohydrate diets on weight loss and lipid levels: a systematic review and meta-analysis. Nutrients. 2020;12(12):3774. source

      Not checked in the free run.

    • cites [58] Seid H, Rosenbaum M. Low carbohydrate and low-fat diets: what we don’t know and why we should know it. Nutrients. 2019;11(11):2749. source

      Not checked in the free run.

    • cites [59] Public Health Collaboration. A summary table of randomised controlled trials comparing low-carb diets of less than 130g carbohydrate per day to low-fat diets of less than 35% fat of total calories compiled by the Public Health Collaboration. 2018. https://phcuk.org/wp-content/uploads/2018/02/Summary-Table-Of-Randomised-Controlled-Trials-Comparing-Low-Carb-To-Low-Fat-Diets-26.02.2018.pdf. Accessed March 3 2021.

      Not checked in the free run.

    • cites [60] Churuangsuk C, Kherouf M, Combet E, Lean M. Low-carbohydrate diets for overweight and obesity: a systematic review of the systematic reviews. Obes Rev. 2018;19(12):1700–18. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    More recent studies have indicated that weight loss is often similar to comparison diets in the long term, but low-carbohydrate diets may have advantages in reducing diabetic medication and reducing triglycerides while increasing HDL cholesterol.

    “More recent studies have indicated that weight loss is often similar to comparison diets in the long term, but low-carbohydrate diets may have advantages in reducing diabetic medication and reducing triglycerides, while increasing HDL cholesterol [51–53, 54••, 55, 56••].”
    Quote in the paperSubstantial claim0 of 5 sources checked
    • cites [51] Ebbeling CB, Feldman HA, Klein GL, Wong JM, Bielak L, Steltz SK, et al. Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial. BMJ. 2018;363. source

      Not checked in the free run.

    • cites [52] Ebbeling C, Knapp A, Johnson A, Wong J, Greco K, Ma C, et al. Effects of a low-carbohydrate diet on cardiometabolic risk factors during weight-loss maintenance: a randomized controlled feeding trial. Current Developments in Nutrition. 2020;4(Supplement_2):625. source

      Not checked in the free run.

    • cites [53] Saslow LR, Daubenmier JJ, Moskowitz JT, Kim S, Murphy EJ, Phinney SD, et al. Twelve-month outcomes of a randomized trial of a moderate-carbohydrate versus very low-carbohydrate diet in overweight adults with type 2 diabetes mellitus or prediabetes. Nutr Diabetes. 2017;7(12):1–6. source

      Not checked in the free run.

    • cites [54••]

      Not checked in the free run.

    • cites [55] Hall KD, Chen KY, Guo J, Lam YY, Leibel RL, Mayer LE, et al. Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. Am J Clin Nutr. 2016;104(2):324–33. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In both metabolic ward studies, low-carbohydrate diets initially resulted in faster total weight loss than low-fat diets, but DXA scans indicated that most of the weight loss was fat-free mass, most likely due to water weight from glycogen depletion.

    “In both studies, the low-carbohydrate diets initially resulted in faster total weight loss than the low-fat diets, but results assessed from DXA scans indicated that most of the weight loss was actually fat-free mass. This is most likely due to the loss of water weight, since during the first few weeks of extreme carbohydrate restriction glycogen stores get depleted and water loss follows [56••].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [56••]

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    The carbohydrate-insulin model asserts that increased consumption of high-glycemic foods produces hormonal changes that promote calorie deposition in adipose tissue, increase hunger, lower energy expenditure, and result in weight gain.

    “The CIM asserts that the increased consumption of high-glycemic foods produces hormonal changes that promote calorie deposition in adipose tissue, increases in hunger, lowers EE, and results in weight gain [4•].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [4•]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    There is dispute about the accuracy of measuring energy expenditure with the doubly labeled water method for individuals on low-carbohydrate diets.

    “Additionally, there is dispute about the accuracy of measuring EE with the DLW method for individuals on low-carbohydrate diets [64, 65].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [64] Ludwig DS, Lakin PR, Wong WW, Ebbeling CB. Scientific discourse in the era of open science: a response to Hall et al. regarding the carbohydrate-insulin model. Int J Obes. 2019;43(12):2355–60. source

      Not checked in the free run.

    • cites [65] Hall KD, Guo J, Chen KY, Leibel RL, Reitman ML, Rosenbaum M, et al. Methodologic considerations for measuring energy expenditure differences between diets varying in carbohydrate using the doubly labeled water method. Am J Clin Nutr. 2019;109(5):1328–34. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A recent review concluded that the effects of weight loss were not related to the degree of carbohydrate restriction.

    “However, in contrast to these findings, a recent review on different degrees of carbohydrate restriction [(1) moderate-carbohydrate diets (40–45% of energy intake, n = 13 trials), (2) low-carbohydrate diets (30–40% of energy intake, n = 16 trials), and (3) very-low-carbohydrate diets (3–30% of energy intake; n = 8 trials)] concluded that the effects of weight loss were not related to the degree of”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [70] Fechner E, Smeets ET, Schrauwen P, Mensink RP. The effects of different degrees of carbohydrate restriction and carbohydrate replacement on cardiometabolic risk markers in humans—a systematic review and meta-analysis. Nutrients. 2020;12(4):991. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Given that more than 40% of energy in the US diet comes from low-quality carbohydrates that are generally high-GI foods contributing to a higher glycemic load, a low-GI or low-GL approach that significantly restricts those foods has substantial overlap with a low-carb diet for improving weight or glycemic control.

    “Nevertheless, given that >40% of energy in the US diet comes from low-quality carbohydrates (e.g., added sugars and refined grains [77] that are, in general, high GI foods contributing to a higher GL, a low GI, or low GL approach that significantly restricts those foods has substantial overlap with a low-carb diet for improving weight or glycemic control.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [77] Shan Z, Rehm CD, Rogers G, Ruan M, Wang DD, Hu FB, et al. Trends in dietary carbohydrate, protein, and fat intake and diet quality among US adults, 1999-2016. JAMA. 2019;322(12):1178–87. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Improvements in triglycerides, HDL-C cholesterol, and lipoprotein insulin resistance were reported to parallel the degree of restriction of carbohydrates.

    “Improvements in triglycerides, HDL-C cholesterol, and lipoprotein insulin resistance were reported to parallel the degree of restriction of carbohydrates [52].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [52] Ebbeling C, Knapp A, Johnson A, Wong J, Greco K, Ma C, et al. Effects of a low-carbohydrate diet on cardiometabolic risk factors during weight-loss maintenance: a randomized controlled feeding trial. Current Developments in Nutrition. 2020;4(Supplement_2):625. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In the Ebbeling et al. study, total energy expenditure was greatest in the lowest-carbohydrate group, with a linear trend of 52 kcal/d per 10% reduction in dietary carbohydrates.

    “Total EE was greatest in the lowest-carbohydrate group, and there was a linear trend of 52 kcal/d per 10% reduction in dietary carbohydrates.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [51] Ebbeling CB, Feldman HA, Klein GL, Wong JM, Bielak L, Steltz SK, et al. Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial. BMJ. 2018;363. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Findings reported by some meta-analyses on low-GI/GL diets are limited by issues such as pooling studies with different definitions for the range of exposures, including studies with inadequately validated dietary instruments, and a lack of clear inclusion and exclusion criteria.

    “However, the findings reported by some meta-analyses are limited by various issues, such as studies being pooled with different definitions for the range of exposures (e.g., tertiles, quartiles, and quintiles), including studies that used inadequately validated dietary instruments, and a lack of clear inclusion and exclusion criteria for selected studies [76••].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [76••]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    For fasting glucose outcomes in studies lasting more than 26 weeks, both diets have a potentially important impact on glucose concentrations, but neither diet resulted in more substantial changes compared to the other (moderate certainty of evidence).

    “For fasting glucose outcomes in studies lasting > 26 weeks, both diets have a potentially important impact on glucose concentrations, but neither diet resulted in more substantial changes compared to the other (moderate certainty of evidence).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [84] van Zuuren EJ, Fedorowicz Z, Kuijpers T, Pijl H. Effects of low-carbohydrate-compared with low-fat-diet interventions on metabolic control in people with type 2 diabetes: a systematic review including GRADE assessments. Am J Clin Nutr. 2018;108(2):300–31. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A 2018 systematic review of 33 RCTs reported that a low-carbohydrate diet compared to a low-fat diet may result in a clinically important reduction in HbA1c (low certainty of evidence) and a small effect on fasting glucose in studies lasting less than 16 weeks (moderate certainty).

    “The review reported that a low-carbohydrate diet compared to a low-fat diet may result in a clinically important reduction in HbA1c (low certainty of evidence) and that a low-carbohydrate diet results in a small effect that may not lead to an important reduction in fasting glucose in studies lasting < 16 weeks (moderate level of certainty in the evidence).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [84] van Zuuren EJ, Fedorowicz Z, Kuijpers T, Pijl H. Effects of low-carbohydrate-compared with low-fat-diet interventions on metabolic control in people with type 2 diabetes: a systematic review including GRADE assessments. Am J Clin Nutr. 2018;108(2):300–31. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Some trials have suggested that individuals with higher insulin secretion respond well to restricting carbohydrate intake for weight loss.

    “Some trials have suggested that individuals with higher insulin secretion respond well to restricting carbohydrate intake for weight loss [50, 69].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [50] Ebbeling CB, Leidig MM, Feldman HA, Lovesky MM, Ludwig DS. Effects of a low–glycemic load vs low-fat diet in obese young adults: a randomized trial. JAMA. 2007;297(19):2092–102. source

      Not checked in the free run.

    • cites [69] Hron BM, Ebbeling CB, Feldman HA, Ludwig DS. Relationship of insulin dynamics to body composition and resting energy expenditure following weight loss. Obesity. 2015;23(11):2216–22. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    There remain questions and issues to resolve regarding the efficacy and effectiveness of low-carbohydrate diets for weight loss.

    “There remain questions and issues to resolve regarding the efficacy and effectiveness of low-carbohydrate diets for weight loss.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Current American Diabetes Association recommendations suggest an individualized approach to macronutrient proportions based on assessment of current dietary patterns and practices, preferences, and metabolic and health goals.

    “Current American Diabetes Association recommendations suggest an individualized approach to macronutrient proportions based on assessment of current dietary patterns and practices, preferences, and metabolic and health goals [30, 78].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [30] Evert AB, Dennison M, Gardner CD, Garvey WT, Lau KHK, MacLeod J, et al. Nutrition therapy for adults with diabetes or prediabetes: a consensus report. Diabetes Care. 2019;42(5):731–54. source

      Not checked in the free run.

    • cites [78] American Diabetes Association. 5. Facilitating behavior change and well-being to improve health outcomes: standards of medical care in diabetes—2021. Diabetes Care. 2021;44(Supplement 1):S53–72. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Suggested mechanisms for the therapeutic use of low-carbohydrate diets for persons with T2DM or insulin resistance include reduction of blood insulin levels and reversal of hepatic insulin resistance.

    “Suggested mechanisms for the therapeutic use of low-carbohydrate diets for persons with T2DM or insulin resistance include reduction of blood insulin levels and reversal of hepatic insulin resistance [82, 83].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [82] Luukkonen PK, Dufour S, Lyu K, Zhang X-M, Hakkarainen A, Lehtimäki TE, et al. Effect of a ketogenic diet on hepatic steatosis and hepatic mitochondrial metabolism in nonalcoholic fatty liver disease. Proc Natl Acad Sci. 2020;117(13):7347–54. source

      Not checked in the free run.

    • cites [83] Cox N, Gibas S, Salisbury M, Gomer J, Gibas K. Ketogenic diets potentially reverse type II diabetes and ameliorate clinical depression: a case study. Diabetes Metab Syndr Clin Res Rev. 2019;13(2):1475–9. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Systematic reviews comparing low-GI/GL dietary patterns lead to improvements in weight loss, glycemic control, blood lipids, and blood pressure.

    “Systematic reviews comparing low-GI/GL dietary patterns lead to improvements in weight loss, glycemic control, blood lipids, and blood pressure [72–75].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [72] Viguiliouk E, Nishi SK, Wolever TM, Sievenpiper JL. Point: glycemic index—an important but oft misunderstood marker of carbohydrate quality. Cereal Foods World. 2018;63(4):158–64.

      Not checked in the free run.

    • cites [73] Chiavaroli L, Kendall CW, Braunstein CR, Mejia SB, Leiter LA, Jenkins DJ, et al. Effect of pasta in the context of low-glycaemic index dietary patterns on body weight and markers of adiposity: a systematic review and meta-analysis of randomised controlled trials in adults. BMJ Open. 2018;8(3):e019438. source

      Not checked in the free run.

    • cites [74] Zafar MI, Mills KE, Zheng J, Regmi A, Hu SQ, Gou L, et al. Low-glycemic index diets as an intervention for diabetes: a systematic review and meta-analysis. Am J Clin Nutr. 2019;110(4):891–902. source

      Not checked in the free run.

    • cites [75] Livesey G, Taylor R, Livesey HF, Buyken AE, Jenkins DJ, Augustin LS, et al. Dietary glycemic index and load and the risk of type 2 diabetes: assessment of causal relations. Nutrients. 2019;11(6):1436. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Type 2 diabetes is characterized by carbohydrate intolerance due to insulin resistance.

    “Type 2 diabetes is characterized by carbohydrate intolerance due to insulin resistance.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Differences in findings may be related to different study settings, namely more controlled efficacy studies versus free-living effectiveness studies.

    “The differences noted above may be related to different study settings—more controlled efficacy studies vs. free-living effectiveness studies.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Low-carbohydrate eating patterns, especially very-low-carbohydrate ketogenic dietary patterns, have been suggested as a way to reduce HbA1c and the need for antihyperglycemic medications in people with T2DM and insulin resistance.

    “Low-carbohydrate eating patterns, especially very low-carbohydrate ketogenic dietary patterns, have been suggested as a way to reduce HbA1c and the need for antihyperglycemic medications in people with T2DM and insulin resistance [30, 81•].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [30] Evert AB, Dennison M, Gardner CD, Garvey WT, Lau KHK, MacLeod J, et al. Nutrition therapy for adults with diabetes or prediabetes: a consensus report. Diabetes Care. 2019;42(5):731–54. source

      Not checked in the free run.

    • cites [81•]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A 2017 RCT by Saslow et al. found that individuals assigned to a very-low-carbohydrate diet had greater reductions in HbA1c and reduced medications more than those on a moderate-carbohydrate diet.

    “Individuals assigned to the very-low-carbohydrate diet had greater reductions in HbA1c and reduced medications more than those on the moderate-carbohydrate diet [53].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [53] Saslow LR, Daubenmier JJ, Moskowitz JT, Kim S, Murphy EJ, Phinney SD, et al. Twelve-month outcomes of a randomized trial of a moderate-carbohydrate versus very low-carbohydrate diet in overweight adults with type 2 diabetes mellitus or prediabetes. Nutr Diabetes. 2017;7(12):1–6. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Very-low-carbohydrate diets compared to more moderate levels have been suggested to be unrealistic for long-term adherence in people with T2DM.

    “It should be noted that very-low-carbohydrate diets compared to more moderate levels have been suggested to be unrealistic for long-term adherence in people with T2DM [89, 94].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [89] Van Wyk H, Davis R, Davies J. A critical review of low-carbohydrate diets in people with type 2 diabetes. Diabet Med. 2016;33(2):148–57. source

      Not checked in the free run.

    • cites [94] Huntriss R, Campbell M, Bedwell C. The interpretation and effect of a low-carbohydrate diet in the management of type 2 diabetes: a systematic review and meta-analysis of randomised controlled trials. Eur J Clin Nutr. 2018;72(3):311–25. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Adherence to study diets was generally poor, and carbohydrate intake between the two diets often deviated substantially from prescribed protocol amounts, often converging towards a moderate intake.

    “Further research is needed as adherence to study diets were generally poor and often the carbohydrate intake between the two diets deviated substantially from prescribed protocol amounts, often converging towards a moderate intake [89, 94].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [89] Van Wyk H, Davis R, Davies J. A critical review of low-carbohydrate diets in people with type 2 diabetes. Diabet Med. 2016;33(2):148–57. source

      Not checked in the free run.

    • cites [94] Huntriss R, Campbell M, Bedwell C. The interpretation and effect of a low-carbohydrate diet in the management of type 2 diabetes: a systematic review and meta-analysis of randomised controlled trials. Eur J Clin Nutr. 2018;72(3):311–25. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The absence of evidence for low-carbohydrate and very-low-carbohydrate diets in T2DM prevention is not evidence of absence of effect, but rather is due to an absence of evidence.

    “However, this is not evidence of absence of effect, but rather this is due to an absence of evidence.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A 2016 review including 12 RCTs reported that a low-carbohydrate diet appeared to have no different effect compared to a high-carbohydrate diet in terms of glycemic control.

    “A 2016 review including 12 RCTs reported that a low-carbohydrate diet appeared to have no different effect compared to a high-carbohydrate diet in terms of glycemic control [89].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [89] Van Wyk H, Davis R, Davies J. A critical review of low-carbohydrate diets in people with type 2 diabetes. Diabet Med. 2016;33(2):148–57. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    There is no consensus on cutoffs for low-carbohydrate and very-low-carbohydrate diets, and definitions of these dietary patterns can vary from study to study.

    “As there is no consensus on cutoffs for low-carbohydrate and very-low-carbohydrate, definitions of these dietary patterns can vary from study to study [15].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [15] Kirkpatrick CF, Bolick JP, Kris-Etherton PM, Sikand G, Aspry KE, Soffer DE, et al. Review of current evidence and clinical recommendations on the effects of low-carbohydrate and very-low-carbohydrate (including ketogenic) diets for the management of body weight and other cardiometabolic risk factors: a scientific statement from the National Lipid Association Nutrition and Lifestyle Task Force. J Clin Lipidol. 2019;13(5):689–711. e1. Comprehensive review of the current evidence base available from recent systematic reviews and meta-analyses on the effects of low-CHO and very-low-CHO diets on bo source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A recent systematic review and meta-analysis reported that low-GI diets in people with impaired glucose tolerance, type 1 diabetes, or type 2 diabetes were effective at reducing HbA1c, BMI, total and LDL cholesterol, and fasting glucose.

    “A recent systemic review and meta-analysis reported that low-GI diets in people with impaired glucose tolerance, type 1 diabetes, or type 2 diabetes were effective at reducing HbA1c, BMI, total and LDL cholesterol, and fasting glucose [74].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [74] Zafar MI, Mills KE, Zheng J, Regmi A, Hu SQ, Gou L, et al. Low-glycemic index diets as an intervention for diabetes: a systematic review and meta-analysis. Am J Clin Nutr. 2019;110(4):891–902. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Unlike the Mediterranean diet, for which long-term efficacy and safety have been observed, low-carbohydrate and very-low-carbohydrate diets lack data on long-term safety, adherence, and efficacy.

    “Unlike other dietary patterns such as the Mediterranean diet for which long-term efficacy and safety have been observed [95, 96], low-carbohydrate and very-low-carbohydrate diets lack data on long-term safety, adherence, and efficacy [97].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [95] Benson G, Pereira RF, Boucher JL. Rationale for the use of a Mediterranean diet in diabetes management. Diabetes Spectr. 2011;24(1):36–40. source

      Not checked in the free run.

    • cites [96] Martín-Peláez S, Fito M, Castaner O. Mediterranean diet effects on type 2 diabetes prevention, disease progression, and related mechanisms. A Review Nutrients. 2020;12(8):2236. source

      Not checked in the free run.

    • cites [97] Sainsbury E, Kizirian NV, Partridge SR, Gill T, Colagiuri S, Gibson AA. Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: a systematic review and meta-analysis. Diabetes Res Clin Pract. 2018;139:239–52. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The non-randomized Virta trial reported that participants in the low-carbohydrate diet group demonstrated improved HbA1c, fasting glucose and insulin, and HOMA-IR after 2 years.

    “The non-randomized Virta trial comparing an individualized low-carbohydrate diet to a convenience sample of usual care adults with T2DM reported that participants in the low-carbohydrate diet group demonstrated improved HbA1c, fasting glucose and insulin, and HOMA-IR after 2 years [81].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [81] Athinarayanan SJ, Adams RN, Hallberg SJ, McKenzie AL, Bhanpuri NH, Campbell WW, et al. Long-term effects of a novel continuous remote care intervention including nutritional ketosis for the management of type 2 diabetes: a 2-year non-randomized clinical trial. Front Endocrinol (Lausanne). 2019;10:348. A non-randomized controlled study comparing an individualized low-carb diet to usual care. Participants in the low-carb diet group demonstrated improved HbA1c, fasting glucose and insulin, and HOMA-IR following 2 years. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Low-GI diets were only found to be effective for weight loss in people with normal glucose tolerance and were not found to be effective in people with glucose tolerance, type 1 diabetes, or type 2 diabetes.

    “Strikingly, low-GI diets were only found to be effective for weight loss in people with normal glucose tolerance and were not found to be effective in people with glucose tolerance, type 1 diabetes, or type 2 diabetes [74, 93].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [74] Zafar MI, Mills KE, Zheng J, Regmi A, Hu SQ, Gou L, et al. Low-glycemic index diets as an intervention for diabetes: a systematic review and meta-analysis. Am J Clin Nutr. 2019;110(4):891–902. source

      Not checked in the free run.

    • cites [93] Zafar M, Mills K, Zheng J, Peng M, Ye X, Chen L. Low glycaemic index diets as an intervention for obesity: a systematic review and meta-analysis. Obes Rev. 2019;20(2):290–315. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationcitation

    Individuals with T2DM must balance the potential mixed impacts of very-low-carbohydrate diets on cardiovascular risk factors, including adverse increases in LDL-C, improvement of glycemic control, positive changes in triglyceride and HDL-C levels, and potential weight change benefits.

    “Individuals with T2DM must also balance the potential mixed impacts of very low carbohydrate diets on cardiovascular risk factors—adverse increases in LDL-C levels, improvement of glycemic control, positive changes in triglyceride and HDL-C levels, and potential weight change benefits as described above [98, 99].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [98] Mansoor N, Vinknes KJ, Veierød MB, Retterstøl K. Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials. Br J Nutr. 2016;115(3):466–79. source

      Not checked in the free run.

    • cites [99] Batch JT, Lamsal SP, Adkins M, Sultan S, Ramirez MN. Advantages and disadvantages of the ketogenic diet: a review article. Cureus. 2020;12(8). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    More than half (53.5%) of the patients in the Virta treatment group experienced a reversal of diabetes with substantial reductions in the use of diabetic medications.

    “More than half (53.5%) of the patients in the treatment group experienced a reversal of diabetes with substantial reductions in the use of diabetic medications [81].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [81] Athinarayanan SJ, Adams RN, Hallberg SJ, McKenzie AL, Bhanpuri NH, Campbell WW, et al. Long-term effects of a novel continuous remote care intervention including nutritional ketosis for the management of type 2 diabetes: a 2-year non-randomized clinical trial. Front Endocrinol (Lausanne). 2019;10:348. A non-randomized controlled study comparing an individualized low-carb diet to usual care. Participants in the low-carb diet group demonstrated improved HbA1c, fasting glucose and insulin, and HOMA-IR following 2 years. source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Compared to participants on a high-carbohydrate diet, low-carbohydrate diet participants sustained greater reductions in diabetes medication requirements and improvements in diurnal blood glucose stability.

    “Compared to participants on a high carbohydrate diet, the low-carbohydrate diet participants sustained greater reductions in diabetes medication requirements and in improvements in diurnal blood glucose stability.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [85] Tay J, Luscombe-Marsh ND, Thompson CH, Noakes M, Buckley JD, Wittert GA, et al. Comparison of low-and high-carbohydrate diets for type 2 diabetes management: a randomized trial. Am J Clin Nutr. 2015;102(4):780–90. source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationnone given

    It is difficult to interpret studies of "low-carbohydrate" diets when definitions are inconsistent, adherence is poor, and documentation of adherence is inadequate.

    “It is difficult to interpret studies of “low-carbohydrate” diets when definitions are inconsistent, adherence is poor, and documentation of adherence is inadequate.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Sustainability of these diets cannot be addressed in studies of less than 1 year in duration.

    “sustainability of these diets cannot be addressed in studies of less than 1 year in duration”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    In some cases the comparison diet was of lower quality, or had no dietary intervention at all, resulting in a worse chance of success than the low-carbohydrate diet.

    “Lastly, many of the studies compared a low-carbohydrate diet to a diet with a different macronutrient composition; however, in some cases the comparison diet was of lower quality, or had no dietary intervention at all, resulting in a worse chance of success than the low-carbohydrate diet [107–109].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [107] Freedland SJ, Allen J, Jarman A, Oyekunle T, Armstrong AJ, Moul JW, et al. A randomized controlled trial of a 6-month low-carbohydrate intervention on disease progression in men with recurrent prostate cancer: Carbohydrate and Prostate Study 2 (CAPS2). Clin Cancer Res. 2020;26(12):3035–43. source

      Not checked in the free run.

    • cites [108] Hallberg SJ, McKenzie AL, Williams PT, Bhanpuri NH, Peters AL, Campbell WW, et al. Effectiveness and safety of a novel care model for the management of type 2 diabetes at 1 year: an open-label, non-randomized, controlled study. Diabetes Ther. 2018;9(2):583–612. source

      Not checked in the free run.

    • cites [109] Morris E, Aveyard P, Dyson P, Noreik M, Bailey C, Fox R, et al. A food-based, low-energy, low-carbohydrate diet for people with type 2 diabetes in primary care: a randomized controlled feasibility trial. Diabetes Obes Metab. 2020;22(4):512–20. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Low-carbohydrate diets may have advantages for reducing appetite, triglycerides, and diabetic medications but with potential adverse effects raising LDL-C cholesterol levels and possible detrimental effects on the microbiome and inflammation.

    “Low-carbohydrate diets may have advantages for reducing appetite, triglycerides, and diabetic medications but with potential adverse effects raising LDL-C cholesterol levels [23, 38, 39] and possible detrimental effects on the microbiome and inflammation [100, 101].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [23] Yamada S. Paradigm shifts in nutrition therapy for type 2 diabetes–nutrition therapy for diabetes. The Keio journal of medicine. 2017;66(3):33–43. source

      Not checked in the free run.

    • cites [38] Gibson AA, Seimon RV, Lee CM, Ayre J, Franklin J, Markovic T, et al. Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. Obes Rev. 2015;16(1):64–76. source

      Not checked in the free run.

    • cites [39] Deemer SE, Plaisance EP, Martins C. Impact of ketosis on appetite regulation—a review. Nutr Res. 2020;77:1–11. source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    Many studies fail to include assessments of dietary adherence, making it challenging to determine the actual carbohydrate intake of participants compared to the prescribed carbohydrate intake.

    “Unfortunately, many studies fail to include assessments of dietary adherence making it challenging to determine the actual carbohydrate intake of participants compared to the prescribed carbohydrate intake.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationcitation

    In general, results from RCTs that assessed low-carbohydrate diets report better weight loss than comparison or control diets in the short term (6 months or less), but beyond 6 months those benefits diminish.

    “In general, results from RCTs that assessed low-carbohydrate diets report better weight loss than comparison or control diets in the short term (i.e., 6 months or less), but beyond 6 months, those benefits diminish [59, 60].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [59] Public Health Collaboration. A summary table of randomised controlled trials comparing low-carb diets of less than 130g carbohydrate per day to low-fat diets of less than 35% fat of total calories compiled by the Public Health Collaboration. 2018. https://phcuk.org/wp-content/uploads/2018/02/Summary-Table-Of-Randomised-Controlled-Trials-Comparing-Low-Carb-To-Low-Fat-Diets-26.02.2018.pdf. Accessed March 3 2021.

      Not checked in the free run.

    • cites [60] Churuangsuk C, Kherouf M, Combet E, Lean M. Low-carbohydrate diets for overweight and obesity: a systematic review of the systematic reviews. Obes Rev. 2018;19(12):1700–18. source

      Not checked in the free run.

62 of 62

  • The paper relies on this without support.

    Body weight alone is a crude measure that fails to capture potentially important differences in lean mass, fat mass, and body water.

    “Body weight alone is a crude measure that fails to capture potentially important differences in lean-mass, fat-mass, and body water.”

  • The paper relies on this without support.

    Adherence is very different between metabolic chamber or feeding studies and free-living conditions.

    “Adherence is very different between metabolic chamber or feeding studies vs. free-living.”

  • The paper relies on this without support.

    If any of the current dietary approaches was strikingly more effective than others, the entire field would have shifted to adopt and promote that approach.

    “If any of the current dietary approaches was strikingly more effective than others, the entire field would have shifted to adopt and promote that approach.”

  • The paper relies on this without support.

    There are more reviews of the existing low-carbohydrate vs. low-fat trials than there are trials.

    “there are apparently more reviews of the existing trials, than there are trials.”

  • The paper relies on this without support.

    There is widespread agreement in the public health community that low quality carbohydrates (e.g., added sugars, refined grains) should be substantially reduced.

    “there is widespread agreement in the public health community that low quality carbohydrates (e.g., added sugars, refined grains) should be substantially reduced”
5 of 5

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • National Lipid Association report is cited as reference 23

    Minor

    The statement attributes its claim to a National Lipid Association Task Force report, but reference 23 is a paper by Yamada. The Task Force report is listed as reference 15.

1 of 1

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Related

Authors
Landry, M. J., Crimarco, A., & Gardner, C. D.
Affiliations
Stanford University (US)
Corresponding author
Gardner, Christopher D.
ORCID
Venue
Current Obesity Reports
Publisher
Springer Science and Business Media LLC
Published
2021-07-23
Volume
10
Issue
3
Pages
409-422
ISSN
2162-4968 (ISSN-L)
DOI
10.1007/s13679-021-00451-z
PMC
PMC9621749
OpenAlex
W3183924568
Semantic Scholar
a0afef04380076b31f9fc0b268a7c6044ea121df
Cited by
31
References
127
Citations by year
2026: 6 · 2025: 10 · 2024: 7 · 2023: 5 · 2022: 3
FWCI
0.50
Type
journal article
Language
en
Open access
Licence
Locations
  • Current Obesity Reports (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
  • eScholarship (California Digital Library) (submittedVersion)
Funders
  • National Heart, Lung, and Blood Institute (T32HL007034)
  • National Institute of Diabetes and Digestive and Kidney Diseases (P30DK116074)
Topics
  • Health Sciences › Medicine › Physiology › Diet and metabolism studies
  • Health Sciences › Medicine › Physiology › Dietary Effects on Health
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Diabetes Management and Research
Keywords
low-carbohydrate diet, weight management, type 2 diabetes, very low carbohydrate diet, low-fat diet, dietary adherence, glycemic control, LDL cholesterol, gut microbiota, inflammation, body composition, diabetes prevention
MeSH terms
Body Weight, Diabetes Mellitus, Type 2, Dietary Carbohydrates, Humans, Diet, Carbohydrate-Restricted

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review