This is the first study, to our knowledge, to estimate the daily per capita cost of food wasted, inedible, and consumed in the US from 2001 to 2016. This study integrated dietary data from nearly 40 thousand adults collected over a 16-year period with nationally-representative data on food waste, food prices, eating location, and food price inflation.

We demonstrate that consumers spent, on average, over one-quarter of their daily food budget on food that ended up being wasted, representing over $3.50 per day. Meat and seafood accounted for the greatest proportion of daily food budgets spent on wasted food, followed by fruits and vegetables, grains, sweets, and dairy. No difference in total food waste expenditure was observed between food consumed at home (FAH) and food consumed away from home (FAFH), but greater expenditure was observed for FAFH meat and seafood and FAH fruits and vegetables.

Others have estimated that daily per capita food waste at the consumer level represented approximately $1.07–1.10 [11, 12], which is lower than estimates presented here ($3.62). However, the estimates from previous studies were derived by applying FAH prices from 2008 to 2009 to all foods reported consumed, which does not account for the important price differences between FAH (e.g., at supermarkets and grocery stores) and FAFH (e.g., at restaurants and vending machines), and does not account for food price inflation that has occurred since that time. Sensitivity analyses revealed that accounting for these differences reduced food price estimates in the present study to $2.58. The remaining gap between the present results and previous studies is likely due to differences in data coverage in the underlying datasets, where NHANES (used in the present study) provides a complete accounting of individual-level data on all foods reported consumed, whereas LAFA (used in previous studies) provides population-level data on the amount of select food commodities available for consumption. In the present study, established methods were utilized to incorporate the strengths of both datasets buy linking them together using FCID, which allowed for an estimation of the amount of waste attributable to each ingredient in each food consumed by each individual.

According to recently-updated food expenditure estimates published by the US Department of Agriculture [24], the average household food expenditure in 2016 was $30.18 [25] (1.95 adults per household [26]=$15.48 per adult), representing 52% of FAH and 48% FAFH [25], which is consistent with our findings (food expenditure was $13.27 per adult, not including alcohol, representing 48% FAH and 52% FAFH). Others have estimated that, using 2001–2004 FAH prices, mean expenditure on consumed food was $4.81 [27] and $5.79 (per 2000 kcal) [28], which straddles our estimate of $5.21 (Model 3).

The present study suggests that the average American consumer spends over $1300 per year ($3.62 per day × 365 days) on food that ends up being wasted, which is greater than the annual expenditure on vehicle gasoline ($1250); apparel ($1207); household heating and electricity ($1149); property taxes ($1046); and household maintenance, repairs, and insurance ($936) for the average single-person household in 2017 [29]. Since individuals report that saving money is the most important motivator for reducing food waste [10], contextualizing the cost of food waste within other common household expenditures can be one avenue to encourage behavior change. Realistically, it may not be possible to eliminate all consumer food waste because households (especially those with children) face competing demands on time, diverse food preferences, and other practical considerations [30], and discarding spoiled food is a key aspect of ensuring appropriate food safety standards in the household. But targeted efforts to reduce food waste can help individuals and households make positive changes toward increasing their food budgets and reducing environmental impact.

The present study demonstrates that meat and seafood, as well as fruits and vegetables, accounted for the greatest value of consumer food waste by food group, cumulatively representing over 60% of the total, which is consistent with previous findings [11, 12]. Importantly, our novel method for distinguishing food waste in the home versus outside of the home yields important new information that can be used by consumers to better target reductions in food waste: the greatest amount of meat and seafood waste (by value) occurred outside of the home ($0.41 in the home vs. $0.94 outside of the home), whereas the greatest amount of fruit and vegetable waste occurred within the home ($0.68 in the home vs. $0.40 outside of the home). Several strategies are available to help consumers navigate these complexities. For example, when eating meat and seafood dishes prepared outside of the home (at restaurants, for example), consumers can strive to match their hunger level with meal portion size by sharing meals and ordering smaller portions [31, 32], and most eating establishments will provide containers for leftover portions [33]. Enhancing consumer educational efforts to reduce fruit and vegetable waste in the household will also be critically important. Consumers may benefit from increased knowledge about how to discern bruises/abrasions from spoilage, how to tell when fruits and vegetables are ripe, and how to prepare and safely store them [30, 34]. The Supplemental Nutrition Assistance Program Education, which provides education and guidance for low-income households to make healthy food choices [35], offers a key platform to increase consumer knowledge of strategies to reduce food waste.

This study is not without limitations. Data on food price inflation were available for only 15 major food categories (from CPI), whereas data on food intake were available for over 8500 individual foods (from NHANES), so linking these data may have contributed to over-generalized estimates of contemporary prices for individual foods. Lack of data availability also prevented analyses of food waste across divergent geographic regions and subpopulations, and more research is needed to estimate variability of food waste across these domains. Estimates of food waste were derived from the LAFA data series, which provides a single estimate of the proportion of each food wasted across years. This limitation prevented a time trend analysis, and required that the same food-specific waste proportions were applied consistently to FAH and FAFH. Furthermore, this limitation made it necessary to apply food-specific waste proportions consistently to all individuals in NHANES, which has precedent in previous studies [6, 36,37,38]. The need to develop innovative methods to merge these datasets, and the additional limitations of doing so, have been noted elsewhere [39]. Some of the datasets used in this study do not include uncertainty estimates (e.g., LAFA), which may have resulted in overly narrow confidence intervals. The expenditures presented in this study do not take into account the cost of household utilities (e.g., water, electricity, natural gas) and appliances used to prepare food, so the full cost of FAH may be greater. Finally, self-reported food intake is subject to measurement error from social desirability bias, with individuals likely over-reporting intake of perceived healthy foods and under-reporting intake of perceived unhealthy foods. Additionally, some individuals may have consumed a portion of their meal outside of the home but consumed the leftovers at home, which could have resulted in mis-categorization of FAH and FAFH in this study. Self-reported dietary data are nonetheless a rich source of information on intake of individual foods on a population level [40]. Overall, this study should not be interpreted as providing perfect estimates of food expenditure; instead, this study represents a novel approach to address important, interdisciplinary knowledge gaps using existing, publicly-available datasets.

The strengths of this study should be considered when interpreting the findings. For the first time, nationally-representative datasets on food intake, food waste, food prices, eating location, and food price inflation were linked to provide a robust measure of the daily per capita cost of consumer food wasted, inedible, and consumed in contemporary dollars. Importantly, this study also introduced a novel method of accounting for the important price differences between FAH and FAFH, thereby filling an important research gap [39]. The large sample size and multi-stage sampling structure of the source data make these findings generalizable to the US adult population, and the implications are far-ranging, from nutrition-related health outcomes to environmental sustainability.