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Cited by 190Muscle metabolism and nutritionNutrition and Health in AgingMuscle Physiology and Disorders

Effects of an omnivorous diet compared with a lactoovovegetarian diet on resistance-training-induced changes in body composition and skeletal muscle in older men

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Campbell, Wayne W, Barton, Marvin L, Cyr-Campbell, Deanna, Davey, Stephanie L, Beard, John L, Parise, Gianni, Evans, William J·1999·The American Journal of Clinical Nutrition
DOI 10.1093/ajcn/70.6.1032
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Abstract

Background Very limited data suggest that meat consumption by older people may promote skeletal muscle hypertrophy in response to resistance training (RT).Objective The objective of this study was to assess whether the consumption of an omnivorous (meat-containing) diet would influence RT-induced changes in whole-body composition and skeletal muscle size in older men compared with a lactoovovegetarian (LOV) (meat-free) diet.Design Nineteen men aged 51-69 y participated in the study. During a 12-wk period of RT, 9 men consumed their habitual omnivorous diets, which provided approximately 50% of total dietary protein from meat sources (beef, poultry, pork, and fish) (mixed-diet group). Another 10 men were counseled to self-select an LOV diet (LOV-diet group).Results Maximal strength of the upper- and lower-body muscle groups that were exercised during RT increased by 10-38% (P < 0.001), independent of diet. The RT-induced changes in whole-body composition and skeletal muscle size differed significantly between the mixed- and LOV-diet groups (time-by-group interactions, P < 0. 05). With RT, whole-body density, fat-free mass, and whole-body muscle mass increased in the mixed diet group but decreased in the LOV- diet group. Type II muscle fiber area of the vastus lateralis muscle increased with RT for all men combined (P < 0.01), and the increase tended to be greater in the mixed-diet group (16.2 +/- 4.4 %) than in the LOV diet group (7.3 +/- 5.1%). Type I fiber area was unchanged with RT in both diet groups.Conclusion Consumption of a meat-containing diet contributed to greater gains in fat-free mass and skeletal muscle mass with RT in older men than did an LOV diet.

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Crossref · 10.1093/ajcn/70.6.1032

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  • Products containing animal and dairy-based proteins contain the highest percentage of EAAs and result in greater hypertrophy and protein synthesis following resistance training when compared to a vegetarian protein-matched control.

    “products containing animal and dairy-based proteins contain the highest percentage of EAAs and result in greater hypertrophy and protein synthesis following resistance training when compared to a vegetarian protein-matched control, which typically lacks one or more EAAs [86, 93, 147].”

    From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [147]

    The Subject characteristics and body composition results report greater gains in fat-free mass and estimated muscle mass with the omnivorous diet during resistance training, although the between-group difference in type II fiber growth was not significant. The Dietary intake section says protein intakes were not significantly different, but the diets were not protein-matched by design. The paper does not compare EAA percentages or measure protein synthesis in these men; the Discussion presents protein synthesis as a possible explanation, not a demonstrated result. (LLM, conf=0.89)

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  • Generally by consuming high-quality, animal-based products (meat, milk, eggs, and cheese) an individual will achieve optimal growth as compared to ingesting only plant proteins.

    “Generally by consuming high-quality, animal-based products (meat, milk, eggs, and cheese) an individual will achieve optimal growth as compared to ingesting only plant proteins [147].”

    From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [147]

    The Results and Conclusion report greater resistance-training-related gains in fat-free mass and skeletal muscle mass among older men eating a meat-containing diet than among those eating a lactoovovegetarian diet. This does not establish optimal growth for individuals generally, or a comparison with a diet containing only plant proteins: the meat-free group also consumed dairy and eggs. (LLM, conf=0.90)

    Experimental — accuracy not yet measured

  • Meat-based diets increase fat-free mass and may specifically increase muscle mass.

    “These results indicate that not only do meat-based diets increase fat-free mass, but also they may specifically increase muscle mass, thus supporting the many benefits of meat-based diets.”

    From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [147]

    The Abstract (indexed pp. 1–3) reports greater gains in fat-free and skeletal muscle mass with a meat-containing diet than with a meat-free diet in older men undergoing resistance training. The claim omits that population and training condition, presenting the finding as a general effect of meat-based diets. The Discussion (indexed pp. 1–3) also cautions that the method used to quantify changes in whole-body muscle mass was unvalidated. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • Vegetarian diets often lack equivalent amounts of protein when compared to omnivorous diets.

    “One key difference is the fact that vegetarian diets often lack equivalent amounts of protein when compared to omnivorous diets [147].”

    From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [147]

    The Discussion (p. 1037) says protein intake trended lower when the men switched to a lactoovovegetarian diet, and Table 5 shows lower mean protein intake than in the mixed-diet group during training. But the Dietary intake section reports that the between-group differences were not statistically significant. This study of older men does not establish that vegetarian diets often contain less protein than omnivorous diets generally. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • Over a 12-week period, whole-body density, fat-free mass, and whole-body muscle mass increased in the meat-sourced diet group but decreased in the lactoovovegetarian diet group in older men who resistance train.

    “Over a 12-week period, whole-body density, fat-free mass, and whole-body muscle mass (as measured by urinary creatinine excretion) increased in the meat-sourced diet group but decreased in the lactoovovegetarian diet group.”

    From International Society of Sports Nutrition Position Stand: protein and exercise (2017) · cites this paper as [147]

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Research works printed but not linked: 1

  1. Guimbal C, Killiman MW. A Na+ dependent creatine transporter in rabbit brain, muscle, heart, and kidney. J Biol Chem 1993;268: 8418-21.

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Authors
Campbell, W. W., Barton, M. L., Cyr-Campbell, D., Davey, S. L., Beard, J. L., Parise, G., & Evans, W. J.
Affiliations
Pennsylvania State University (US)
Corresponding author
Campbell, Wayne W
ORCID
Venue
The American Journal of Clinical Nutrition
Publisher
Elsevier BV
Published
1999-12
Volume
70
Issue
6
Pages
1032-1039
ISSN
0002-9165 (ISSN-L)
DOI
10.1093/ajcn/70.6.1032
OpenAlex
W2127632101
Cited by
190
References
38
Citations by year
2026: 3 · 2025: 6 · 2024: 7 · 2023: 10 · 2022: 7 · 2021: 6 · 2020: 5 · 2019: 7 · 2018: 6 · 2017: 12 · 2016: 10 · 2015: 13 · 2014: 10 · 2013: 5 · 2012: 8
FWCI
1.65
Type
journal article
Language
en
Open access
Licence
Locations
  • American Journal of Clinical Nutrition (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Pennsylvania State University
  • National Institutes of Health (7r01ag011811-07, AG11811)
  • National Institute on Aging (R01-AG-11811, R29AG013409, R29-AG-13409)
  • National Center for Research Resources (M01 RR10732, M01RR010732)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Physiology › Nutrition and Health in Aging
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Muscle Physiology and Disorders
Keywords
omnivorous diet, resistance training, older men, body composition, skeletal muscle hypertrophy, fat-free mass, muscle mass, meat consumption, dietary protein, muscle fiber area, maximal strength, vastus lateralis
MeSH terms
Aged, Body Composition, Creatine, Diet, Humans, Male, Meat, Middle Aged, Obesity, Phosphocreatine, Diet, Vegetarian, Exercise, Muscle, Skeletal

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