Relationship between food waste, diet quality, and environmental sustainability

Fruits and vegetables and mixed fruit and vegetable dishes accounted for 39% of food waste.

“Fruits and vegetables and mixed fruit and vegetable dishes accounted for 39% of food waste, followed by dairy (17%), meat and mixed meat dishes (14%), and grains and grain mixed dishes (12%).”

Wasted food represents about 29% of total daily energy intake.

“Over 800 kcal (795–840 kcal) were wasted per person per day, representing about 29% of total daily energy intake (S4 Table).”

Nearly 26% of food was wasted by US consumers every day from 2007-2014.

“Nearly 26% (95% CI: 25–26%) of food was wasted by US consumers every day from 2007–2014 (S3 Table).”

Approximately 1.8 billion pounds of nitrogen fertilizer were applied to wasted cropland.

“Approximately 1.8 billion pounds (1.8–1.9 billion pounds) of nitrogen fertilizer (S7 Table), 1.5 billion pounds (1.4–1.5 billion pounds) of phosphorus (P2O5) fertilizer (S8 Table), and 2.3 billion pounds (2.2–2.3 billion pounds) of potash (K2O) fertilizer (S9 Table) were applied to wasted cropland, largely attributable to cropland used to produce feed grains and oilseeds and hay.”

Higher diet quality was not associated with fertilizer waste.

“Importantly, higher quality diets were associated with greater food waste but less waste of cropland; as well as greater waste of irrigation water and pesticides, but not fertilizers.”

Over 800 kcal were wasted per person per day.

“Over 800 kcal (795–840 kcal) were wasted per person per day, representing about 29% of total daily energy intake (S4 Table).”

Higher quality diets were associated with greater amounts of wasted irrigation water.

“Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste.”

• Also stated in: § Daily per capita food waste and diet quality · plain

  “Higher diet quality was also associated with greater waste of irrigation water (P<0.001) and pesticides (P<0.001; Fig 5).”

• Also stated in: § Discussion · plain

  “as well as greater waste of irrigation water and pesticides, but not fertilizers.”

Wasted food accounts for 7% of annual cropland acreage.

“This accounts for 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage.”

• Also stated in: § Discussion · hedged

  “This accounts for about 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage.”

Higher quality diets were associated with less cropland waste.

“but less cropland waste.”

• Also stated in: § Daily per capita food waste and diet quality · plain

  “Higher diet quality was associated (P = 0.029) with less cropland used to produce wasted food (Fig 4).”

• Also stated in: § Discussion · plain

  “but less waste of cropland”

Nearly 4.2 trillion gallons of irrigation water were applied to cropland used to produce uneaten food.

“Nearly 4.2 trillion gallons (95% CI: 4.1–4.3 trillion gallons) of irrigation water were applied to cropland that was used to produce uneaten food (S5 Table).”

Wasted food accounts for one-quarter of daily food (by weight) available for consumption.

“This accounts for 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage.”

• Also stated in: § Discussion · hedged

  “This accounts for about 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage.”

Nearly 780 million pounds of pesticides were applied to wasted cropland.

“Nearly 780 million pounds (759–797 million pounds) of pesticides were applied to wasted cropland (S6 Table), mostly to cropland used to produce fruit (337 million pounds), feed grains and oilseeds (158 million pounds), and vegetables (133 million pounds).”

US consumers wasted 422 g of food per person per day from 2007-2014.

“This analysis finds that US consumers wasted 422g of food per person daily, with 30 million acres of cropland used to produce this food every year.”

• Also stated in: § Daily per capita food and nutrient waste · plain

  “US consumers wasted 422 g (95% CI: 409–434 g)–nearly one pound–of food per person per day from 2007–2014 (Table 1 and S2 Table).”

• Also stated in: § Discussion · boosted

  “We demonstrate that the average American wasted about 422 g (~ 1 pound) of food every day from 2007–2014, and about 30 million acres of cropland were used to produce this food every year.”

Approximately 2.3 billion pounds of potash (K2O) fertilizer were applied to wasted cropland.

“Approximately 1.8 billion pounds (1.8–1.9 billion pounds) of nitrogen fertilizer (S7 Table), 1.5 billion pounds (1.4–1.5 billion pounds) of phosphorus (P2O5) fertilizer (S8 Table), and 2.3 billion pounds (2.2–2.3 billion pounds) of potash (K2O) fertilizer (S9 Table) were applied to wasted cropland, largely attributable to cropland used to produce feed grains and oilseeds and hay.”

Food waste varied from a mean of 295 g among those with the lowest diet quality to a mean of 535 g among those with the highest diet quality.

“Food waste varied from a mean of 295 g (95% CI: 282–308 g) among those with the lowest diet quality (quintile 1) to a mean of 535 g (501–568 g) among those with the highest diet quality (quintile 5).”

Higher diet quality was associated with greater waste of fruits and vegetables and mixed dishes.

“Among individual foods and dishes, higher diet quality was associated with greater waste of dairy (P<0.001), soup (P = 0.001), nuts and seeds (P = 0.017), fruits and vegetables and mixed dishes (P<0.001), table oils and salad dressing (P<0.001), and salty snacks (P<0.001; S1 Table).”

Approximately 1.5 billion pounds of phosphorus (P2O5) fertilizer were applied to wasted cropland.

“Approximately 1.8 billion pounds (1.8–1.9 billion pounds) of nitrogen fertilizer (S7 Table), 1.5 billion pounds (1.4–1.5 billion pounds) of phosphorus (P2O5) fertilizer (S8 Table), and 2.3 billion pounds (2.2–2.3 billion pounds) of potash (K2O) fertilizer (S9 Table) were applied to wasted cropland, largely attributable to cropland used to produce feed grains and oilseeds and hay.”

Higher quality diets were associated with greater amounts of food waste.

“Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste.”

• Also stated in: § Daily per capita food waste and diet quality · plain

  “Higher diet quality was associated (P<0.001) with greater food waste (Fig 3).”

• Also stated in: § Discussion · plain

  “Importantly, higher quality diets were associated with greater food waste but less waste of cropland; as well as greater waste of irrigation water and pesticides, but not fertilizers.”

Higher diet quality was associated with less land used to produce wasted grains.

“In particular, higher diet quality was associated with less land used to produce wasted grains (P = 0.004), sweeteners (P<0.001), and hay (P = 0.017), and more land used to produce wasted fruits (P = 0.001), vegetables (P = 0.010), legumes (P = 0.032), and nuts (P = 0.042; S11 Table).”

Higher diet quality was associated with more land used to produce wasted fruits.

“In particular, higher diet quality was associated with less land used to produce wasted grains (P = 0.004), sweeteners (P<0.001), and hay (P = 0.017), and more land used to produce wasted fruits (P = 0.001), vegetables (P = 0.010), legumes (P = 0.032), and nuts (P = 0.042; S11 Table).”

Wasted food accounts for 30% of daily calories available for consumption.

“This accounts for 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage.”

• Also stated in: § Discussion · hedged

  “This accounts for about 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage.”

Higher diet quality was associated with more land used to produce wasted vegetables.

“In particular, higher diet quality was associated with less land used to produce wasted grains (P = 0.004), sweeteners (P<0.001), and hay (P = 0.017), and more land used to produce wasted fruits (P = 0.001), vegetables (P = 0.010), legumes (P = 0.032), and nuts (P = 0.042; S11 Table).”

Higher quality diets were associated with greater amounts of wasted pesticides.

“Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste.”

• Also stated in: § Daily per capita food waste and diet quality · plain

  “Higher diet quality was also associated with greater waste of irrigation water (P<0.001) and pesticides (P<0.001; Fig 5).”

• Also stated in: § Discussion · plain

  “as well as greater waste of irrigation water and pesticides, but not fertilizers.”

The mean overall HEI-2015 score was 58 out of 100.

“The mean overall HEI-2015 score measuring diet quality was 58 (out of 100), and ranged from a mean of 32 in quintile 1 to a mean of 82 in quintile 5 (S10 Table).”

30 million acres of cropland were used to produce wasted food annually.

“with 30 million acres of cropland used to produce this food every year.”

• Also stated in: § Annual cropland and agricultural amendments used to produce wasted food · plain

  “Annually, wasted food was grown on the equivalent of over 30 million acres (95% CI: 29.3–30.8 million acres) of cropland, representing 7.7% (7.5–7.9%) of all harvested cropland in the US (Fig 2A).”

• Also stated in: § Discussion · plain

  “about 30 million acres of cropland were used to produce this food every year.”

A substantially greater proportion of fruits and vegetables were wasted compared to other foods.

“Yet a substantially greater proportion of fruits and vegetables were wasted compared to other foods, and fruits and vegetables have higher agricultural input needs (per unit of land area) than most other crops.[38]”

The present study's estimates of cropland (30 million acres) and fertilizer (5.6 billion pounds) used to produce wasted food were lower than Kummu et al.'s estimates (44 million acres and 7.3 billion pounds).

“Our estimates of cropland (30 million acres) and fertilizer (5.6 billion pounds) used to produce wasted food were lower than Kummu et al. (44 million acres of cropland and 7.3 billion pounds of fertilizer),[14]”

• cites [14] M Kummu, 2012, Lost food, wasted resources: global food supply chain losses and their impacts on freshwater, cropland, and fertiliser use, Sci Total Environ sourceNot checked yet

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The present study's estimates of cropland and fertilizer used to produce wasted food were lower than Birney et al.'s estimates (61 million acres and 8.7 billion pounds).

“Our estimates of cropland and fertilizer used to produce wasted food were also lower than Birney et al. (61 million acres of cropland and 8.7 billion pounds of fertilizer),[51]”

• cites [51] CI Birney, 2017, An assessment of individual foodprints attributed to diets and food waste in the United States, Environ Res Lett sourceNot checked yet

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Higher quality diets contained greater amounts of fruits and vegetables.

“Higher quality diets contained greater amounts of fruits and vegetables, which require far less land to produce compared to many other foods.[46, 47]”

Production of fruits and vegetables wasted in high proportions carries environmental burdens, particularly due to relatively high rates of pesticide use and irrigation.

“However, as our results highlight, production of fruits and vegetables wasted in high proportions carries environmental burdens as well, particularly due to relatively high rates of pesticide use and irrigation.”

Substantial amounts of nutrients are embodied in wasted food.

“We also show that substantial amounts of nutrients are embodied in wasted food.”

The average person living in America wastes nearly one pound of food daily.

“Using novel, interdisciplinary methods, we demonstrate that the average person living in America wastes nearly one pound of food daily.”

Over 20% of food is lost or wasted at the consumer level each year in the US.

“over 20% of food is lost or wasted at the consumer level each year,[24] accounting for 225–290 pounds per person per year[16, 24, 25] and 760–790 kcal per person per day.[16, 24–26]”

• cites [24] J Buzby, 2014Not checked yet

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This is the first study to integrate diverse analytical methods from nutritional epidemiology, agricultural science, and biophysical modeling to investigate the relationship between consumer food waste, diet quality, nutrient waste, and embodied agricultural resources.

“This is the first study, to the best of our knowledge, to integrate diverse analytical methods from the fields of nutritional epidemiology, agricultural science, and biophysical modeling to investigate the relationship between consumer food waste, diet quality, nutrient waste, and embodied agricultural resources.”

The association between higher diet quality and greater food waste is largely due to fruits and vegetables.

“This is largely due to fruits and vegetables, which are health-promoting and require small amounts of cropland, but require substantial amounts of agricultural inputs.”

• AssumptionRests on an assumption: Fruits and vegetables require small amounts of cropland but substantial amounts of agricultural inputs.

Globally, enough food is wasted every year to feed nearly 2 billion people a 2,100 kcal/day diet.

“Globally, enough food is wasted every year to feed nearly 2 billion people a 2,100 kcal/day diet,[14] which amplifies the negative environmental externalities associated with agriculture and increases resource scarcity.”

• cites [14] M Kummu, 2012, Lost food, wasted resources: global food supply chain losses and their impacts on freshwater, cropland, and fertiliser use, Sci Total Environ sourceNot checked yet

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LAFA provides estimates of food loss (including waste) at multiple stages in the food system for over 200 individual foods.

“LAFA is curated by USDA Economic Research Service (ERS) and provides estimates of food loss (including waste) at multiple stages in the food system for over 200 individual foods.”

• cites [36] Loss-adjusted Food Availability (LAFA) data series [Internet]. 1980-2015.Available at: <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://www.ers.usda.gov/data-products/food-availability-per-capita-data-system/loss-adjusted-food-availability-documentation/" xlink:type="simple">https://www.ers.usda.gov/data-products/food-availability-per-capita-data-system/loss-adjusted-food-availability-documentation/</ext-link> (verified 03 January 2018).Not checked yet

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Food waste is an important indicator of sustainability because it embodies the sum of resources used to produce uneaten food.

“Food waste is an important indicator of sustainability because it embodies the sum of resources used to produce uneaten food, including cropland, agricultural chemicals like fertilizers and pesticides, and irrigation water; in other words, these inputs are used to grow food that is ultimately wasted by consumers.”

The modeling approach may have underestimated the amount of cropland used to produce wasted food.

“so our approach may have underestimated the amount of cropland used to produce wasted food.”

Substantial waste of packaged but perishable goods like dairy may be generated by consumers' limited understanding of date labels, leading them to discard unspoiled food.

“For these products, substantial waste may be generated by consumers’ limited understanding of date labels on food packages (e.g. “sell by”, “use by”, and “best before”) that leads them to discard unspoiled food.[24, 56]”

• cites [24] J Buzby, 2014Not checked yet

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• cites [56] NLW Wilson, 2017, Food waste: The role of date labels, package size, and product category, Food Qual Prefer sourceNot checked yet

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Self-reported dietary data are subject to measurement error, such that some individuals may over-report perceived healthy foods and under-report perceived unhealthy foods.

“self-reported dietary data are subject to measurement error, such that some individuals may over-report consumption of perceived healthy foods and under-report consumption of perceived unhealthy foods.[48, 49]”

• cites [48] RA Roark, 2013, Fruit and vegetable intake: Issues with definition and measurement, Public Health Nutr sourceNot checked yet

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• cites [49] JV Woodside, 2013, Fruits and vegetables: measuring intake and encouraging increased consumption, The Proceedings of the Nutrition Society sourceNot checked yet

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Fruits and vegetables require far less land to produce compared to many other foods.

“Higher quality diets contained greater amounts of fruits and vegetables, which require far less land to produce compared to many other foods.[46, 47]”

• cites [46] CJ Peters, 2007, Testing a complete-diet model for estimating the land resource requirements of food consumption and agricultural carrying capacity: The New York State example, Renew Agric Food Syst sourceNot checked yet

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• cites [47] Buzby JC, Wells HF, Vocke G. Possible Implications for US Agriculture from Adoption of Select Dietary Guidelines. Washington, DC: USDA Economic Research Service (ERS); 2006. Contract No.: Economic Research Report Number 31. Available at: <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://www.ers.usda.gov/publications/pub-details/?pubid=45694" xlink:type="simple">https://www.ers.usda.gov/publications/pub-details/?pubid=45694</ext-link> (verified 03 January 2018).Not checked yet

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Consuming the nutrients embodied in wasted food in addition to the food actually consumed would lead to higher intake of overconsumed nutrients like saturated fat, sodium, and added sugar.

“Yet we recommend against this interpretation because this would also lead to higher intake of overconsumed nutrients like saturated fat, sodium, and added sugar, which have been linked to negative health outcomes.[52]”

• cites [52] US Department of Health and Human Services and US Department of Agriculture. Dietary Guidelines for Americans 2015–2020, Chapter 1. Washington, DC; 2015–2020. Available at: <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://health.gov/dietaryguidelines/" xlink:type="simple">http://health.gov/dietaryguidelines/</ext-link> (verified 25 January 2018).Not checked yet

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The balance between increasing fruit and vegetable consumption and reducing waste is especially challenging for individuals with limited time and money, including families with children.

“This can be especially challenging for individuals with limited time and money, including families with children who face competing food preferences in the household.[54]”

• cites [54] M Hebrok, 2017, Household food waste: Drivers and potential intervention points for design–An extensive review, J Clean Prod sourceNot checked yet

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Self-reported dietary data are still useful for comparing dietary patterns between groups.

“but self-reported dietary data are still useful for comparing dietary patterns between groups.[50]”

• cites [50] AF Subar, 2015, Addressing Current Criticism Regarding the Value of Self-Report Dietary Data, J Nutr sourceNot checked yet

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Most households face competing challenges between the cost of food, the time and energy needed to prepare and store food, diverse taste preferences among household members, and other practical considerations.

“Most households face competing challenges between the cost of food, the time and energy need to prepare and store food, diverse taste preferences among members of the household (particularly children), and other practical considerations.[24]”

• cites [24] J Buzby, 2014Not checked yet

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The modeling approach led to greater accuracy in computing point estimates and variances than would have been possible with more aggregated data from international sources.

“We believe this approach led to greater accuracy in computing point estimates and variances than would have been possible had we used more aggregated data from international sources.”

Diet quality and environmental sustainability are not necessarily interdependent.

“Thus, diet quality and environmental sustainability are not necessarily interdependent, and improving diet quality and reducing environmental impact”

This measurement error may have led to an over-estimation of total food waste.

“This may have led to an over-estimation of total food waste (given that fruits and vegetables, which are widely understood to be health-promoting, are wasted at relatively high rates)”

The study's estimates of food waste included cooking losses, such as fats and oils left in the pan after cooking, due to lack of data availability.

“Due to lack of data availability, our estimates of food waste included cooking losses, such as fats and oils left in the pan after cooking.”

The present study used food intake data from WWEIA, the only nationally representative data on self-reported food intake in the US.

“In the present study, we used data on food intake from WWEIA, the only nationally-representative data on self-reported food intake in the US.”

It is not feasible to prevent all food waste at the consumer level given limited time, perishability, and other logistical challenges.

“And given limited time, perishability, and other logistical challenges, it is not feasible to prevent all food waste at the consumer level.[53]”

• cites [53] S Romani, 2018, Domestic food practices: A study of food management behaviors and the role of food preparation planning in reducing waste, Appetite sourceNot checked yet

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The US provides high quality, publicly available data on agricultural inputs for individual crops rather than only aggregated crop categories.

“We used this approach because the US provides high quality, publically available data on agricultural inputs for individual crops rather than for only aggregated crop categories.”

A recent study found a positive relationship between the amount of food selected at each meal and the amount of plate waste.

“In a recent study, researchers found a positive relationship between the amount of food selected at each meal and the amount of plate waste, suggesting a need to better align satiety levels with food portioning.[55]”

• cites [55] BE Roe, 2018, Plate waste of adults in the United States measured in free-living conditions, PLoS One sourceNot checked yet

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Spoiled food is a health risk, particularly for young children and people over age 65.

“Spoiled food is a health risk, particularly for young children with under-developed immune systems, as well as for people over age 65 who may experience age-related declines in sensory function and must rely on date labels. [62, 63]”

• cites [62] D Gilliss, 2013, Incidence and trends of infection with pathogens transmitted commonly through food—Foodborne Diseases Active Surveillance Network, 10 U.S. sites, 1996–2012, Morb Mortal Weekly RepNot checked yet

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• cites [63] JL Smith, 1998, Foodborne Illness in the Elderly, J Food Prot sourceNot checked yet

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Fruits and vegetables have higher agricultural input needs per unit of land area than most other crops.

“Yet a substantially greater proportion of fruits and vegetables were wasted compared to other foods, and fruits and vegetables have higher agricultural input needs (per unit of land area) than most other crops.[38]”

• cites [38] Agricultural Surveys [Internet]. 2011-2015.Available at: <ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://www.nass.usda.gov/Quick_Stats/" xlink:type="simple">http://www.nass.usda.gov/Quick_Stats/</ext-link> (verified 07 March 2018).Not checked yet

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LAFA is the most comprehensive and contemporary data available at the national level for food waste rates.

“While we recognize that food waste rates likely vary in ways not captured by LAFA, this dataset is the most comprehensive and contemporary data available at the national level.”