Relationship between food waste, diet quality, and environmental sustainability

Abstract

Improving diet quality while simultaneously reducing environmental impact is a critical focus globally. Metrics linking diet quality and sustainability have typically focused on a limited suite of indicators, and have not included food waste. To address this important research gap, we examine the relationship between food waste, diet quality, nutrient waste, and multiple measures of sustainability: use of cropland, irrigation water, pesticides, and fertilizers. Data on food intake, food waste, and application rates of agricultural amendments were collected from diverse US government sources. Diet quality was assessed using the Healthy Eating Index-2015. A biophysical simulation model was used to estimate the amount of cropland associated with wasted food. 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. 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. Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste. 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. These results suggest that simultaneous efforts to improve diet quality and reduce food waste are necessary. Increasing consumers' knowledge about how to prepare and store fruits and vegetables will be one of the practical solutions to reducing food waste.

Fig 1. Data sources, compilation and output.

LAFA, Loss-adjusted Food Availability data series; FCID, Food Commodity Intake Database; WWEIA, What We Eat In America ¹Grains, dark green vegetables, red and orange vegetables, legumes, starchy vegetables, other vegetables. fruit, milk and yogurt, cheese and other dairy, soy milk, nuts, tofu, beef, pork, chicken, turkey, eggs, fish, plant oils, dairy fats, lard and tallow, and sweeteners. ²All dishes; meat and mixed meat dishes (beef and beef mixed dishes; pork and pork mixed dishes; poultry and poultry mixed dishes; seafood and seafood mixed dishes; meat sandwiches, burgers, sausages, and hotdogs; bacon; and other meat dishes) eggs and egg dishes; dairy (milk and cream, cheese); soup; grains and mixed grain dishes (bread; breakfast cereal; pancakes, waffles, and French toast; pastas and grain mixtures; pizza and calzones; and grain-based desserts); nuts and seeds; fruits and vegetables in mixed dishes (whole fruit and mixed fruit dishes; fruit/vegetable juice; dark green vegetables; yellow and orange vegetables; tomatoes and tomato mixtures; legumes; other vegetables); potatoes and potato mixed dishes; margarine, table oils, and salad dressings; salty snacks; Mexican dishes; other foods and dishes. ³Calories; total protein; total carbohydrates; added sugars; fiber; total and individual saturated fatty acids; total and individual monounsaturated fatty acids; total and individual saturated fatty acids; cholesterol; vitamins (A, B₁, B₂, B₆, B₁₂ niacin, folate, choline, C, D, K, E); minerals (calcium, phosphorous, magnesium, iron, zinc, copper, sodium, potassium, selenium); and total and individual carotenoids. ⁴All cropland, grains, fruits, vegetables, legumes, nuts, sweeteners, feed grains and oilseeds, hay, and cropland pasture. ⁵Nitrogen, phosphorus, and potash. ⁶Sum of insecticides, herbicides, and fungicides.

Fig 2

a) Percent of all harvested cropland wasted by category, and b) percent of each type of harvested cropland wasted. Total cropland wasted = 30.02 million acres (95% CI: 29.29–30.76 million acres), representing 7.7% (7.5–7.9%) of total harvested cropland.

Fig 3. Total food waste by Healthy Eating Index-2015 quintile.

HEI-2015, Healthy Eating Index-2015. Higher HEI-2015 quintiles indicate higher diet quality.

Fig 4. Total cropland used to produce wasted food, by diet quality.

HEI-2015, Healthy Eating Index-2015.

Fig 5

Annual amount of a) irrigation water, b) nitrogen fertilizer, c) phosphorus (P₂O₅) fertilizer, d) potash (K₂O) fertilizer, and e) pesticides applied to cropland used to produce wasted food, by diet quality.