Addressing the carbon footprint, healthfulness, and costs of self-selected diets in the USA: a population-based cross-sectional study

Body composition and CO2 dietary emissions

Background

The amount and quality of foods consumed not only impact on individual health, as reflected in body composition, but they could influence on greenhouse gas emissions and then, on environment.

Aim

This study aims to assess the relationship between the body composition and the CO2 emissions resulting from the dietary choices of an adult population.

Design

A cross-sectional study on baseline data from 778 participants aged 55-75 years old, with metabolic syndrome (MetS) as part of the PREDIMED-Plus study.

Methods

Food intake was registered using a validated semi quantitative 143-item food frequency questionnaire. The amount of CO2 emitted was calculated using data from the Agribalyse® 3.0.1 database. Anthropometry (body weight, height, and waist, and hip circumference, and body mass index) was determined by usual measurements, and body composition (fat mass, visceral fat, muscular mass, fat free mass, and total body water) were assessed by bioimpedance.

Results

CO2 emissions were linearly and positively associated with weight, waist circumference, visceral fat, fat free mass, total body water and energy intake.

Conclusion

Body composition is associated with dietary CO2 emissions. The higher total body water, fat free mass, and body weight, the higher the dietary CO2 emissions were, following a linear relationship.

Clinical trial registration

http://www.isrctn.com/ISRCTN89898870, ISRCTN89898870.

Modeled sustainability impacts of increasing pork consumption among adults in the United States

Introduction

Little is known about the role of pork in sustainable diet patterns, given that it is often aggregated with other animal proteins or not evaluated at all. To address this gap, this study modeled the sustainability impacts of replacing different protein foods with pork in a nationally representative sample of adults in the United States (US).

Methods

Data on dietary intake, greenhouse gas emissions (GHGE), cumulative energy demand, water scarcity footprint, land, pesticides, fertilizer nutrients, food prices, and diet quality were obtained from publicly available repositories. A food substitution model was constructed to evaluate the change in each sustainability impact when 1-3 servings of beef, poultry, seafood, eggs, or legumes were replaced by pork.

Results

Modeled substitution of beef with pork was associated with reductions in GHGE, land, pesticides, and fertilizer nutrients by 11-35%, and substitution of seafood with pork was associated with reductions in cumulative energy demand by 6% and diet cost by <1%. All other substitutions led to an increase in sustainability impacts of up to 5%, including all outcomes associated with substituting poultry, eggs, and legumes with pork.

Discussion

The US federal government can play an important role in improving data collection methods that distinguish between pork and other meats. This can facilitate further research to evaluate sustainability trade-offs, which can inform clinical practice and public policy to support informed food choices for consumers.

Greater adherence to the Mediterranean diet pattern in the United States is associated with sustainability trade-offs

BACKGROUND

The Mediterranean diet pattern has been consistently associated with health benefits but less is known about the association with environmental and economic sustainability in the United States (US). This information is needed to support sustainable policy agendas and provide consumers with evidence-based information needed to make informed food choices. This study fills this research gap by evaluating the environmental sustainability and diet cost associated with adherence to the Mediterranean diet pattern in the US.

METHODS

Dietary data from the National Health and Nutrition Examination Survey (2011-2018, n = 17,079) were merged with data on environmental impacts (greenhouse gas emissions, cumulative energy demand, water scarcity footprint), agricultural resource demand (land, fertilizer nutrients, and pesticides), and food prices from multiple publicly available databases. The Mediterranean Diet Score was used to evaluate adherence to the Mediterranean diet pattern. Multivariable linear regression models were used to evaluate the association between adherence to the Mediterranean diet pattern and environmental impacts, agricultural resource demand, and diet cost. Sensitivity analyses were used to evaluate adjustment of loss and waste and food-away-from-home prices.

RESULTS

Greater adherence to the Mediterranean diet pattern was associated with lower greenhouse gas emissions (p < 0.001), land use (p < 0.001), fertilizer nutrient use (p < 0.001), and pesticide use (p < 0.001), higher water scarcity footprint (p < 0.001) and diet cost (p < 0.001), and no change in cumulative energy demand (p = 0.147). These changes were driven primarily by reduced intake of animal-sourced foods such as beef dishes, meat sandwiches, and dairy, as well as decreased intake of refined carbohydrate foods such as refined grain dishes and soft drinks.

CONCLUSIONS

This nationally representative study demonstrates that greater adherence to the Mediterranean diet pattern is associated with sustainability trade-offs. These findings have implications for the development of sustainable dietary guidelines and clinical practice guidelines that can be used to inform consumer food choices.

MUSAE: Fusion of art and technology to address challenges in food and health

There is an urgent need to transform our current food system to improve population health/wellbeing and planetary health. A number of challenges exist in order to achieve this. Artists, with their innate ability to use imagination to envision future needs and solve problems, represent a key group in this transformation. The project MUSAE brings together artists with experts from different disciplines to define an innovative model to integrate artistic collaboration in the (European) Digital innovation hubs (E-DIHs). They will employ the Design Futures Art-Driven (DFA) methods to enable artists and a range of companies involved in food production and distribution to develop innovative products and services that address key issues in the food system. MUSAE will run two residencies involving 23 artists and 11 SMEs working with three main technologies-Artificial Intelligence, Wearables and Robotics-to envision the future scenarios for societal needs and technology applications, as well as develop future-driven prototypes, thus opening new markets and innovations in the area of food.

Augmenting the National Nutrition Data System to Promote Diet Sustainability Analyses

Research on sustainable diets has become an important and growing area of the nutrition field, but recent studies have pointed to a lack of sustainability metrics and methods that are hindering research and policy progress. To fill this gap, the White House National Strategy on Hunger, Nutrition, and Health calls for increased funding to improve metrics, data collection, and research to address all domains of sustainability, which include nutrition/health, economic, environmental, and social domains. Commodity recipe databases, such as the Food Commodity Intake Database (FCID), are important tools for conducting diet sustainability analyses because they translate mixed dishes from dietary surveys, such as the National Health and Nutrition Examination Survey (NHANES), into commodity ingredients. These ingredients have been linked to data on environmental impacts and economic costs from other databases, thus facilitating collaboration between nutrition researchers, environmental scientists, economists, and others. These linkages cannot be made with other components of the national nutrition data system, such as the Food Patterns Equivalents Database (FPED), because the disaggregated food groups from them are not relevant for examining environmental impacts. Although the NHANES is conducted on an ongoing basis, and FPED is continually updated, the FCID has not been officially updated since 2010. This severely limits advancements in sustainability research and related policy analyses. In this commentary, we argue that the federal government should promote this diet sustainability work by integrating a commodity recipe database into the national nutrition data system, and updating it on a regular basis, as it does with other component databases.

Risk Factors of Wasting-Based Malnutrition in the Flood-Affected Areas of Pakistan: A Cross-Sectional Study

The current study aimed to find the risk factors of wasting in flood-affected areas of Khyber Pakhtunkhwa, Pakistan. Sociodemographic and anthropometric data was collected. Children living in large family are 2.59 times more likely to be wasted (AOR = 2.59, 95% confidence interval (CI): 1.10, 6.10; p value = .029) and children living in medium size family are 2.23 times more likely to be wasted (AOR = 2.23, 95% CI: 1.03, 4.80; p value = .04) as compared to children in small family size. The study underscores the need for targeted interventions to address the identified risk factors and mitigate the impact of flooding on child nutrition.

Effects of red meat taxes and warning labels on food groups selected in a randomized controlled trial

BACKGROUND

High consumption of red and processed meat contributes to both health and environmental harms. Warning labels and taxes for red meat reduce selection of red meat overall, but little is known about how these potential policies affect purchases of subcategories of red meat (e.g., processed versus unprocessed) or of non-red-meat foods (e.g., cheese, pulses) relevant to health and environmental outcomes. This study examined consumer responses to warning labels and taxes for red meat in a randomized controlled trial.

METHODS

In October 2021, we recruited 3,518 US adults to complete a shopping task in a naturalistic online grocery store. Participants were randomly assigned to one of four arms: control (no warning labels or tax), warning labels only (health and environmental warning labels appeared next to products containing red meat), tax only (prices of products containing red meat were increased 30%) or combined warning labels + tax. Participants selected items to hypothetically purchase, which we categorized into food groups based on the presence of animal- and plant-source ingredients (e.g., beef, eggs, pulses), meat processing level (e.g., processed pork versus unprocessed pork), and meat species (e.g., beef versus pork). We assessed the effects of the warning labels and tax on selections from each food group.

RESULTS

Compared to control, all three interventions led participants to select fewer items with processed meat (driven by reductions in processed pork) and (for the tax and warning labels + tax interventions only) fewer items with unprocessed meat (driven by reductions in unprocessed beef). All three interventions also led participants to select more items containing cheese, while only the combined warning labels + tax intervention led participants to select more items containing processed poultry. Except for an increase in selection of pulses in the tax arm, the interventions did not affect selections of fish or seafood (processed or unprocessed), eggs, or plant-based items (pulses, nuts & seeds, tofu, meat mimics, grains & potatoes, vegetables).

CONCLUSIONS

Policies to reduce red meat consumption are also likely to affect consumption of other types of foods that are relevant to both health and environmental outcomes.

TRIAL REGISTRATION

NCT04716010 on www.

CLINICALTRIALS

gov .

Mixed diets can meet nutrient requirements with lower carbon footprints

Achieving sustainable dietary change is essential for safeguarding human and environmental health. However, dietary recommendations based on broad food groups may not accurately reflect real-world realities because individuals select and consume dishes with multiple food items influenced by diverse context-specific factors. Therefore, here we explored the sustainability trade-offs of dietary choices at the dish level through an optimization modeling approach tested in Japan. We estimated the nutritional quality, price, and carbon footprint of major Japanese dishes and examined 16 dietary scenarios to identify options that meet the nutritional requirements and minimize carbon footprint. Overall, mixed diets contain more combinations of dishes that meet nutritional requirements with lower carbon footprints compared to more restrictive dietary scenarios. We argue that the approach developed here enables a better understanding of dietary trade-offs, complements existing methods, and helps identify sustainable diets by offering nuanced information at the national and sub-national levels.

Developing messages to encourage healthy, sustainable dietary substitutions: A qualitative study with US emerging adults

Prior research shows that adopting simple dietary substitutions (e.g., replacing beef with poultry or plant-based entrees) can improve dietary quality and reduce the negative environmental consequences of food production, but little is known about how to encourage people to adopt these substitutions. This study aimed to examine reactions to messages encouraging healthy, sustainable dietary substitutions among emerging adults ages 18-25. We conducted four online focus groups with a diverse sample of US emerging adults (n = 28; 61% female). Focus groups explored emerging adults' reactions to messages encouraging them to adopt three target dietary substitutions: replacing beef and pork with poultry and plant-based entrees; replacing juice with whole fruit; and replacing dairy milk with non-dairy milk. We transcribed discussions verbatim and adopted a thematic approach to analyzing the transcripts. Results showed that participants perceived messages to be most effective at encouraging the target dietary substitutions when the messages: encouraged specific, achievable dietary changes; linked these dietary changes to clear consequences; included personally relevant content; included statistics; were succinct; and used a positive tone. Across the target dietary substitutions, two message topics (small changes, big benefits, which emphasized how small dietary changes can have large positive health and environmental impacts, and warning, which discussed the negative health and environmental impacts of dietary choices) were generally perceived to be most effective. A few participants expressed doubt that the target dietary substitutions would have meaningful environmental impacts. Results suggest that campaign messages to encourage healthy, sustainable dietary substitutions may be more effective if the messages make the target dietary substitutions seem achievable and use statistics to clearly describe the positive impacts of making these changes.

Plant-Based Fermented Beverages: Nutritional Composition, Sensory Properties, and Health Benefits

Plant-based beverages have gained consumers' attention for being the main substitutes for dairy milk, especially for people with lactose intolerance, milk allergies, and a prevalence of hypercholesterolemia. Moreover, there is a growing demand for a more sustainable diet and plant-based lifestyle due to concerns related to animal wellbeing, environmental impacts linked to dairy production, and the rising cost of animal-derived foods. However, there are some factors that restrict plant-based beverage consumption, including their nutritional quality and poor sensory profile. In this context, fermentation processes can contribute to the improvement of their sensory properties, nutritional composition, and functional/bioactive profile. In particular, the fermentation process can enhance flavor compounds (e.g., acetoin and acetic acid) while decreasing off-flavor components (e.g., hexanal and hexanol) in the substrate. Furthermore, it enhances the digestibility and bioavailability of nutrients, leading to increased levels of vitamins (e.g., ascorbic acid and B complex), amino acids (e.g., methionine and tryptophan), and proteins, while simultaneously decreasing the presence of anti-nutritional factors (e.g., phytic acid and saponins). In contrast, plant-based fermented beverages have been demonstrated to possess diverse bioactive compounds (e.g., polyphenols and peptides) with different biological properties (e.g., antioxidant, anti-inflammatory, and antihypertensive). Therefore, this article provides an overview of plant-based fermented beverages including their production, technological aspects, and health benefits.

Transitioning to a Plant-Based Menu in Childcare: Identifying the Nutritional, Financial, and Logistical Considerations

International health organizations have called for a shift towards more plant-based foods as a way of promoting both individual health and environmental sustainability. Given the high percentage of children in Canada who attend childcare and the high volume of food provided in childcare, transitioning menus to incorporate plant-based foods could have important implications for both planetary and child health. The purpose of this case study is to describe a childcare centre's transition to a plant-based menu. A detailed nutritional analysis of the menu was conducted. The financial and logistical implications of the transitions to a plant-based menu were also assessed. Nutritional analysis revealed that the plant-based menu met or exceeded the daily nutrient requirement for all the key nutrients explored. Financially, the transition led to a 9% reduction in food costs. Logistically, the transition led to improved efficiency and safety with regard to food preparation, with substantially fewer tailored meals due to allergies and dietary restrictions required after the transition. These novel findings are relevant for food service administrators interested in transitioning to a plant-based menu as well as public health dietitians who could support the transition.

Partial substitutions of animal with plant protein foods in Canadian diets have synergies and trade-offs among nutrition, health and climate outcomes

Dietary guidelines emphasize the consumption of plant protein foods, but the implications of replacing animal with plant sources on a combination of diet sustainability dimensions are unknown. Using a combination of data from a national nutrition survey, greenhouse gas emissions from dataFIELD and relative risks from the Global Burden of Disease Study 2017, we assess the impact of partially substituting red and processed meat or dairy with plant protein foods in Canadian self-selected diets on nutrition, health and climate outcomes. The substitutions induced minor changes to the percentage of the population below requirements for nutrients of concern, but increased calcium inadequacy by up to 14% when dairy was replaced. Replacing red and processed meat or dairy increased life expectancy by up to 8.7 months or 7.6 months, respectively. Diet-related greenhouse gas emissions decreased by up to 25% for red and processed meat and by up to 5% for dairy replacements. Co-benefits of partially substituting red and processed meat with plant protein foods among nutrition, health and climate outcomes are relevant for reshaping consumer food choices in addressing human and planetary health.

Simple dietary substitutions can reduce carbon footprints and improve dietary quality across diverse segments of the US population

Changing what foods we eat could reduce environmental harms and improve human health, but sweeping dietary change is challenging. We used dietary intake data from a nationally representative sample of 7,753 US children and adults to identify simple, actionable dietary substitutions from higher- to lower-carbon foods (for example, substituting chicken for beef in mixed dishes such as burritos, but making no other changes to the diet). We simulated the potential impact of these substitutions on dietary carbon emissions and dietary quality. If all consumers who ate the high-carbon foods instead consumed a lower-carbon substitute, the total dietary carbon footprint in the United States would be reduced by more than 35%. Moreover, if adopted, these substitutions would improve consumers' overall dietary quality by 4-10%, with benefits projected for all age, gender, and racial and ethnic groups. These results suggest that a 'small changes' approach could be a valuable starting point for addressing diet's impact on climate and health.

The role of a starch-based diet in solving existential challenges for the 21st century

Diet plays a fundamental role in our major chronic diseases, in climate change, and in our resistance to infectious diseases. The eating patterns that best support the health of people and our planet are based on traditional starchy staples. Historically, a wide variety of starches have provided the bulk of the food for most of the people who have walked our Earth. For example, rice has been food for Asians, corn for Central Americans, potatoes for people of the Andes, and for the Middle East, "the bread basket of the world," food has meant wheat and barley. Focusing on our ethnicities can expose altruistic natures, and before it is too late, allow us to make the change from destructive animal-food based-diets to plant-food based-diets; ones that are health-supporting for people and our planet.

Demographic and Socioeconomic Correlates of Disproportionate Beef Consumption among US Adults in an Age of Global Warming

Concern for the environment when making dietary choices has grown as the contribution of the food sector to global greenhouse gas emissions becomes more widely known. Understanding the correlates of beef eating could assist in the targeting of campaigns to reduce the consumption of high-impact foods. The objective of this study was to identify the demographic, socioeconomic, and behavioral correlates of disproportionate beef consumption in the United States. We analyzed 24-h dietary recall data from adults (n = 10,248) in the 2015-2018 National Health and Nutrition Examination Survey (NHANES). Disproportionate beef consumption was defined as an intake greater than four ounce-equivalents per 2200 kcal. Associations of this indicator variable with gender, age, race/ethnicity, education, family income, diet knowledge, and away-from-home meals were assessed using logistic regression, incorporating survey design and weighting. Disproportionate beef diets were consumed by 12% of individuals, but accounted for half of all beef consumed. Males were more likely than females (p < 0.001) to consume these diets. This relationship was seen in all bivariate and multivariable models. Older adults, college graduates, and those who looked up the MyPlate educational campaign online were less likely (p < 0.01) to consume a disproportionate beef diet. While almost one-third of reported consumption came from cuts of beef (e.g., steak or brisket), six of the top ten beef sources were mixed dishes: burgers, meat mixed dishes, burritos and tacos, frankfurters, soups, and pasta. Efforts to address climate change through diet modification could benefit from targeting campaigns to the highest consumers of beef, as their consumption accounts for half of all beef consumed.

Greater adherence to the Dietary Guidelines for Americans is associated with lower diet-related greenhouse gas emissions but higher costs

Introduction

Few studies have evaluated the sustainability of popular diet patterns in the US, which limits policy action and impedes consumer efficacy to make sustainable dietary changes. This study filled this gap by evaluating the relationship between diet quality, greenhouse gas emissions (GHGE), and diet cost for plant-based, restricted carbohydrate, low grain, low fat, and time restricted diet patterns.

Methods

Dietary data were retrieved from the National Health and Nutrition Examination Survey (2011-2018, n = 8,146) and linked with data on GHGE and food prices from publicly available databases. Diet quality was measured using the Healthy Eating Index-2015. The present study (1) compared the mean diet quality, GHGE, and diet cost between diet patterns, (2) evaluated the association of diet quality to GHGE and diet cost for each diet pattern, and (3) estimated the contribution of food sources to GHGE and diet cost for each diet pattern.

Results

Higher diet quality was associated with lower GHGE for the general population and for most diet patterns (p < 0.01) except for the plant-based and time restricted diet patterns (p > 0.05). Higher diet quality was associated with higher cost for the general population and for all dietary patterns (p < 0.01) except the time restricted diet pattern (p > 0.05). Protein foods, mostly beef, accounted for the largest share of GHGE (29-40%) and diet cost (28-47%) for all diet patterns except plant-based.

Discussion

Higher diet quality was associated with lower GHGE but was often accompanied by higher diet cost. These sustainability trade-offs can help inform major policy discussions in the US and shed light on further research needs in the area of food systems transformation.

YOLO-Based Model for Automatic Detection of Broiler Pathological Phenomena through Visual and Thermal Images in Intensive Poultry Houses

The increasing broiler demand due to overpopulation and meat imports presents challenges in poultry farming, including management, disease control, and chicken observation in varying light conditions. To address these issues, the development of AI-based management processes is crucial, especially considering the need for detecting pathological phenomena in intensive rearing. In this study, a dataset consisting of visual and thermal images was created to capture pathological phenomena in broilers. The dataset contains 10,000 images with 50,000 annotations labeled as lethargic chickens, slipped tendons, diseased eyes, stressed (beaks open), pendulous crop, and healthy broiler. Three versions of the YOLO-based algorithm (v8, v7, and v5) were assessed, utilizing augmented thermal and visual image datasets with various augmentation methods. The aim was to develop thermal- and visual-based models for detecting broilers in complex environments, and secondarily, to classify pathological phenomena under challenging lighting conditions. After training on acknowledged pathological phenomena, the thermal YOLOv8-based model demonstrated exceptional performance, achieving the highest accuracy in object detection (mAP50 of 0.988) and classification (F1 score of 0.972). This outstanding performance makes it a reliable tool for both broiler detection and pathological phenomena classification, attributed to the use of comprehensive datasets during training and development, enabling accurate and efficient detection even in complex environmental conditions. By employing both visual- and thermal-based models for monitoring, farmers can obtain results from both thermal and visual viewpoints, ultimately enhancing the overall reliability of the monitoring process.

Environmental and Climate Impact Perceptions in University Students: Sustainability Motivations and Perceptions Correspond With Lower Red Meat Intake

BACKGROUND

Red meat production is a leading contributor to food-related greenhouse gas emissions. Decreasing red meat intake can mitigate climate change and lower risk of diet-related diseases.

OBJECTIVE

The goal of this study is to evaluate university students' perceptions of climate-friendly behaviors and to assess how these perceptions are associated with the frequency of red meat intake.

DESIGN

Cross-sectional survey SETTING: A large, public California university and a large, public Michigan university PARTICIPANTS: Undergraduate students from a California university (n = 721) and a Michigan university (n = 568) MAIN OUTCOME MEASURES: Perceptions of climate-friendly behaviors and frequency of red meat intake STATISTICAL ANALYSIS: Differences in perceptions by student characteristics were compared using t-tests and one-way analysis of variance. Associations between perceptions of climate-friendly behaviors and red meat intake frequency were examined using generalized linear models, adjusted for sociodemographic covariates.

RESULTS

Across both universities, students rated reducing meat intake as less effective than other climate change mitigation behaviors such as recycling and using less plastic. However, students who reported (1) making food and beverage choices that "are good for the environment," (2) making food and beverage choices that "reduce climate change impact," or (3) agreeing that "eating less meat is an effective way to combat climate change" reported 10% to 25% lower frequency of red meat intake for each point higher on the agreement scale. In contrast, making food and beverage choices motivated by health was not associated with frequency of red meat intake.

CONCLUSIONS

Sustainability motivations and perceptions of meat's climate impact were associated with lower frequency of red meat intake, despite the overall moderate rating of eating less meat as an effective climate change mitigator. This research lends support to behavioral interventions, public education campaigns, and policies aiming to reinforce sustainable dietary patterns in young adults.

Greenhouse gas emissions, cost, and diet quality of specific diet patterns in the United States

BACKGROUND

Major policy agendas are calling for accelerated investment in research that addresses the impact of diet patterns on multiple domains of sustainability.

OBJECTIVE

To evaluate the comparative greenhouse gas emissions, diet cost, and diet quality of plant-based, low grain, restricted carbohydrate, low fat, and time restricted diet patterns on a daily per capita basis.

DESIGN

Dietary data from the National Health and Nutrition Examination Survey (2013-2016, n=4,025) were merged with data on greenhouse gas emissions (GHGE) and food prices from multiple databases. The Healthy Eating Index-2015 was used to measure diet quality.

RESULTS

The plant-based diet pattern had the lowest GHGE (3.5 kg CO2eq, 95% CI: 3.3, 3.8 kg CO2eq) and among the lowest diet cost ($11.51, 95% CI: $10.67, $12.41), but diet quality (45.8, 95% CI: 43.3, 48.5) was similar (P>0.005) to most other diet patterns. All of the sustainability impacts of the low grain diet pattern were intermediate. The restricted carbohydrate diet pattern had the highest diet cost ($18.46, 95% CI: $17.80, $19.13) but intermediate diet quality (46.8, 95% CI: 45.7, 47.9) and moderate-to-high GHGE (5.7 kg CO2eq, 95% CI: 5.4, 5.9 kg CO2eq). The low fat diet pattern had the highest diet quality (52.0, 95% CI: 50.8, 53.1) and intermediate GHGE (4.4 kg CO2eq, 95% CI: 4.1, 4.6 kg CO2eq) and diet cost ($14.53, 95% CI: $13.73, $15.38). The time restricted diet pattern had among the lowest diet quality score (42.6, 95% CI: 40.8, 44.6), had GHGE similar to most other diet patterns (4.6 kg CO2eq, 95% CI: 4.2, 5.0 kg CO2eq), and low-to-moderate diet cost ($12.34, 95% CI: $11.38, $13.40).

CONCLUSIONS

Most diet patterns were associated with sustainability trade-offs. The nature of those trade-offs can help inform discussions on food and nutrition policy in the US, including the National Strategy on Hunger, Nutrition, and Health, and future Dietary Guidelines for Americans.

Popular diets as selected by adults in the United States show wide variation in carbon footprints and diet quality

BACKGROUND

Carbon footprints of vegetarian, pescatarian, and other popular diets have been studied previously, but mostly as idealized versions modeled to meet dietary recommendations. Less is known about the footprints of popular diets as they are consumed by US adults, and thus the potential trade-offs with diet quality for free-living individuals.

OBJECTIVES

This study estimated the carbon footprint and diet quality of popular diets as selected by a nationally representative sample of US consumers, including the recently trending keto- and paleo-style diets.

METHODS

The 2005-2010 NHANES 24-h recall data were used to categorize individual adult diets (n = 16,412) into 6 types: vegan, vegetarian, pescatarian, paleo, keto, and all other diets, referred to here as omnivore diets. Average daily greenhouse gas emissions in kilograms of carbon dioxide equivalents per 1000 kcal (kg CO2-eq/1000 kcal) were calculated for each diet by matching our previously developed database to NHANES individual diet data. Diet quality was determined using the Healthy Eating Index (HEI) and the Alternate Healthy Eating Index. Survey-weighted ordinary least-squares regression was used to assess mean differences in diets.

RESULTS

The average carbon footprints of vegan (0.69 ± 0.05 kg CO2-eq/1000 kcal) and vegetarian (1.16 ± 0.02) diets were lower (P < 0.05) than those of the pescatarian (1.66 ± 0.04), omnivore (2.23 ± 0.01), paleo (2.62 ± 0.33), or keto (2.91 ± 0.27) diets. Mean HEI scores were highest for pescatarian diets (58.76 ± 0.79) and higher (P < 0.05) for vegetarian (51.89 ± 0.74) than for omnivore (48.92 ± 0.33) or keto (43.69 ± 1.61) diets.

CONCLUSIONS

Our results highlight the nuances when evaluating the nutritional quality of diets and their carbon footprints. On average, pescatarian diets may be the healthiest, but plant-based diets have lower carbon footprints than other popular diets, including keto- and paleo-style diets.

Impact of Health, Environmental, and Animal Welfare Messages Discouraging Red Meat Consumption: An Online Randomized Experiment

BACKGROUND

Reducing red meat consumption is a key strategy for curbing diet-related chronic diseases and mitigating environmental harms from livestock farming. Messaging interventions aiming to reduce red meat consumption have focused on communicating the animal welfare, health, or environmental harms of red meat. Despite the popularity of these 3 approaches, it remains unknown which is most effective, as limited studies have compared them side by side.

OBJECTIVE

Our aim was to evaluate responses to red-meat-reduction messages describing animal welfare, health, or environmental harms.

DESIGN

This was an online randomized experiment.

PARTICIPANTS

In August 2021, a convenience sample of US adults was recruited via an online panel to complete a survey (n = 2,773 nonvegetarians and vegans were included in primary analyses).

INTERVENTION

Participants were randomly assigned to view 1 of the 4 following messages: control (neutral, non-red meat message), animal welfare, health, or environmental red-meat-reduction messages.

MAIN OUTCOME MEASURES

After viewing their assigned message, participants ordered hypothetical meals from 2 restaurants (1 full service and 1 quick service) and rated message reactions, perceptions, and intentions.

STATISTICAL ANALYSES PERFORMED

Logistic and linear regressions were performed.

RESULTS

Compared with the control message, exposure to the health and environmental red-meat-reduction messages reduced red meat selection from the full-service restaurant by 6.0 and 8.8 percentage points, respectively (P = .02 and P < .001, respectively), while the animal welfare message did not (reduction of 3.3 percentage points, P = .20). None of the red-meat-reduction messages affected red meat selection from the quick-service restaurant. All 3 red-meat-reduction messages elicited beneficial effects on key predictors of behavior change, including emotions and thinking about harms.

CONCLUSIONS

Red-meat-reduction messages, especially those describing health or environmental harms, hold promise for reducing red meat selection in some types of restaurants. Additional interventions may be needed to discourage red meat selection across a wider variety of restaurants, for example, by making salient which menu items contain red meat.

Ready meals, especially those that are animal-based and cooked in an oven, have lower nutritional quality and higher greenhouse gas emissions and are more expensive than equivalent home-cooked meals

OBJECTIVE

To examine whether ready meals and equivalent home-cooked meals differ in nutritional quality indicators, greenhouse gas emissions (GHGE) and cost.

DESIGN

We performed a cross-sectional analysis of meal data from the National Diet and Nutrition Survey (NDNS) nutrient databank (2018/19). Additional data on nutrient composition, cost and cooking-related GHGE were calculated and compared between fifty-four ready meals and equivalent home-cooked meals.

SETTING

The UK.

PARTICIPANTS

Not applicable.

RESULTS

Ready meals, overall and those that were animal-based, had significantly higher levels of free sugar compared with equivalent home-cooked meals (P < 0·0001 and P < 0·0004, respectively). Animal-based ready meals had significantly higher levels of GHGE (P < 0·001), whereas the cost of ready meals, overall, was significantly higher (P < 0·001), compared with equivalent home-cooked meals. Animal-based meals, whether ready meals or equivalent homemade meals, had significantly higher levels of protein (P < 0·0001), contained significantly more kilocalories (P = 0·001), had significantly higher levels of GHGE (P < 0·0001) and were significantly more expensive (P < 0·0001), compared with plant-based meals. Overall, plant-based meals home-cooked on the gas or electric stove had the lowest GHGE and cost, whereas animal-based oven-cooked ready meals had the highest levels of GHGE and were most expensive.

CONCLUSIONS

Ready meals have lower nutritional quality and higher GHGE and are more expensive than equivalent home-cooked meals, especially those meals that are animal-based and prepared in an oven.

Food Costs of Children and Adolescents Consuming Vegetarian, Vegan or Omnivore Diets: Results of the Cross-Sectional VeChi Youth Study

The aim was to analyse the total food costs and the impact of food groups on total food costs among vegetarian, vegan and omnivore children and adolescents in Germany. Based on three-day weighed dietary records of 6–18-year-old children and adolescents of the VeChi Youth Study, the total daily food costs and food group costs (both EUR/day, EUR/1000 kcal) of a vegetarian (n = 145 records), vegan (n = 110) and omnivore (n = 135) diet were calculated. Minimum retail prices of 1000 empirically selected foods reported in the dietary records were linked to individual food intakes. The group differences were analysed using ANCOVA or Kruskal-Wallis tests. Vegans had the highest energy adjusted total food costs at 2.98 EUR/1000 kcal, vegetarians the lowest at 2.52 EUR/1000 kcal. Omnivores also had significantly higher costs than vegetarians with 2.83 EUR/1000 kcal/1000 kcal (p = 0.01), but the total costs did not differ significantly between omnivores and vegans (EUR/d and EUR/1000 kcal). Compared to vegetarians, vegans had significantly higher expenditures (EUR/day) on fruit (p = 0.0003), vegetables (p = 0.006), dairy alternatives (p = 0.0003) and legumes/nuts/seeds (p = 0.0003). Expenditure on starchy foods was significantly higher in the vegetarian or vegan than in the omnivore diet (p = 0.0003). Omnivores spent a quarter of their total food costs on animal source foods (25%), which is equivalent to the sum of food costs for legumes/nuts/seeds, dairy alternatives and meat alternatives in vegans and additionally dairy in vegetarians. The VeChi Youth Study indicated that financial constraints are not necessarily a barrier to switching to a more plant-based diet.

Application of the IoT in the Food Supply Chain─From the Perspective of Carbon Mitigation

With the rising demands on supply chain transparency and food security, the rapid outspread of the Internet of Things (IoT) to improve logistical efficiency, and the rising penetration of sensor technology into daily life, the extensive integration of the IoT in the food sector is well anticipated. A perspective on potential life cycle trade-offs in regard to the type of integration is necessary. We conduct life cycle assessment (LCA) integrated with shelf life-food loss (SL-FL) models, showing an overall 5-fold leverage on carbon reduction, which is diet dependent and a function of income. Meat presents the highest leverage, 35 ± 11-times, owing to its high carbon footprint. Two-thirds (65%) of global sensors (1 billion) engaged in monitoring fruits and vegetables can mitigate less than 7% of the total reduced carbon emissions. Despite the expected carbon emission reductions, widespread adoption of the IoT faces multiple challenges such as high costs, difficulties in social acceptance, and regional variability in technological development. Furthermore, changes in the distribution of transportation resources and dealer service models, requirements regarding the accuracy of sensor data analysis, efficient and persistent operation of devices, development of agricultural infrastructure, and farmer education and training have all increased uncertainty. Nonetheless, the research trend in smart sensors toward smaller chips and the potential integration of machine learning or blockchain as further steps make it possible to leverage these advantages to facilitate market penetration. These insights facilitate the future optimization of the application of IoT sensors for sustainability.

Do diets with higher carbon footprints increase the risk of mortality? A population-based simulation study using self-selected diets from the USA

OBJECTIVE

Are diets with a greater environmental impact less healthy? This is a key question for nutrition policy, but previous research does not provide a clear answer. To address this, our objective here was to test whether American diets with the highest carbon footprints predicted greater population-level mortality from diet-related chronic disease than those with the lowest.

DESIGN

Baseline dietary recall data were combined with a database of greenhouse gases emitted in the production of foods to estimate a carbon footprint for each diet. Diets were ranked on their carbon footprints and those in the highest and lowest quintiles were studied here. Preventable Risk Integrated Model (PRIME), an epidemiological modelling software, was used to assess CVD and cancer mortality for a simulated dietary change from the highest to the lowest impact diets. The diet-mortality relationships used by PRIME came from published meta-analyses of randomised controlled trials and prospective cohort studies.

SETTING

USA.

PARTICIPANTS

Baseline diets came from adults (n 12 865) in the nationally representative 2005-2010 National Health and Nutrition Examination Survey.

RESULTS

A simulated change at the population level from the highest to the lowest carbon footprint diets resulted in 23 739 (95 % CI 20 349, 27 065) fewer annual deaths from CVD and cancer. This represents a 1·83 % (95 % CI 1·57 %, 2·08 %) decrease in total deaths. About 95 % of deaths averted were from CVD.

CONCLUSIONS

Diets with the highest carbon footprints were associated with a greater risk of mortality than the lowest, suggesting that dietary guidance could incorporate sustainability information to reinforce health messaging.

Diet Sustainability Analyses Can Be Improved With Updates to the Food Commodity Intake Database

Diet sustainability analyses inform policymaking decisions and provide clinicians and consumers with evidence-based information to make dietary changes. In the United States, the Food Commodity Intake Database (FCID) provides a crosswalk for integrating nationally representative data on food intake from the National Health and Nutrition Examination Survey (NHANES) with data on sustainability outcomes from other publicly available databases. However, FCID has not been updated since 2010 and does not link with contemporary NHANES data, which limits further advancements in sustainability research. This study fills this research gap by establishing novel linkages between FCID and NHANES 2011-2018, comparing daily per capita food intake with and without these linkages, and making these data publicly available for use by other researchers. To update FCID, two investigators independently established novel data linkages, a third investigator resolved discrepancies, and a fourth investigator audited linkages for accuracy. Dietary data were acquired from nearly 45,000 adults from 2001 to 2018, and food intake was compared between updated vs. non-updated FCID versions. Total food intake from 2011 to 2018 was 5-23% higher using the updated FCID compared to the non-updated version, and intake was over 100% higher in some years for some food categories including poultry, eggs, legumes, starchy vegetables, and tropical oils (P < 0.001 for all comparisons). Further efforts may be needed to create new food composition data to reflect new products and reformulations that enter the food supply over time. This study removes a barrier to further diet sustainability analyses by establishing a data crosswalk between contemporary NHANES and other publicly available databases on agricultural resource use, environmental impacts, and consumer food expenditures.

Awareness of and reactions to health and environmental harms of red meat among parents in the United States

OBJECTIVE

Evidence of the health and environmental harms of red meat is growing, yet little is known about which harms may be most impactful to include in meat reduction messages. This study examined which harms consumers are most aware of and which most discourage them from wanting to eat red meat.

DESIGN

Within-subjects randomised experiment. Participants responded to questions about their awareness of, and perceived discouragement in response to, eight health and eight environmental harms of red meat presented in random order. Discouragement was assessed on a 1-to-5 Likert-type scale.

SETTING

Online survey.

PARTICIPANTS

544 US parents.

RESULTS

A minority of participants reported awareness that red meat contributes to health harms (ranging from 8 % awareness for prostate cancer to 28 % for heart disease) or environmental harms (ranging from 13 % for water shortages and deforestation to 22 % for climate change). Among specific harms, heart disease elicited the most discouragement (mean = 2·82 out of 5), followed by early death (mean = 2·79) and plants and animals going extinct (mean = 2·75), though most harms elicited similar discouragement (range of means, 2·60-2·82). In multivariable analyses, participants who were younger, identified as Black, identified as politically liberal, had higher general perceptions that red meat is bad for health and had higher usual red meat consumption reported being more discouraged from wanting to eat red meat in response to health and environmental harms (all P < 0·05).

CONCLUSIONS

Messages about a variety of health and environmental harms of red meat could inform consumers and motivate reductions in red meat consumption.

Impact of Dietary Meat and Animal Products on GHG Footprints: The UK and the US

Direct and indirect greenhouse gas (GHG) emissions from the ~30+ billion animals consumed as food each year contribute ~14–16% of the global total. The aim of this research is to determine the contribution of meat and animal products to individual GHG footprints. Top-down estimates of GHG emissions from each livestock species are determined using livestock numbers, types, and region-specific emission factors. Comparing livestock emissions with those from individual countries, cattle rank as the third largest emitter after China and the United States (US). The largest uncertainty in these emissions calculations is in the range of emissions factors. Global top-down calculations indicate that the per capita GHG footprint from livestock emissions alone are approximately 1 tCO2eyr−1. For the United Kingdom (UK) and the US, the calculated GHG livestock-related footprints are 1.1 tCO2eyr−1 and 1.6 tCO2eyr−1 per person, respectively. Bottom-up calculations focused on the UK and the US from consumption figures indicated emissions related to meat consumption are approximately 1.3–1.5 tCO2eyr−1 per person. Comparing dietary changes with other ways of reducing GHG footprints indicates removing dietary meat is similar to avoiding one long-haul flight each year and a larger reduction than driving 100 miles less each week.

Nutritional Quality, Environmental Impact and Cost of Ultra-Processed Foods: A UK Food-Based Analysis

Food-based analyses of the healthiness, environmental sustainability and affordability of processed and ultra-processed foods are lacking. This paper aimed to determine how ultra-processed and processed foods compare to fresh and minimally processed foods in relation to nutritional quality, greenhouse gas emissions and cost on the food and food group level. Data from the National Diet and Nutrition Survey nutrient databank year 11 (2018/2019) were used for this analysis. Median and bootstrapped medians of nutritional quality (NRF8.3 index), greenhouse gas emissions (gCO2-equivalents) and cost (in GBP) were compared across processing categories. An optimal score based on the medians was created to identify the most nutritional, sustainable, and affordable options across processing categories. On a per 100 kcal basis, ultra-processed and processed foods had a lower nutritional quality, lower greenhouse gas emissions, and were cheaper than minimally processed foods, regardless of their total fat, salt and/or sugar content. The most nutritious, environmentally friendly, and affordable foods were generally lower in total fat, salt, and sugar, irrespective of processing level. The high variability in greenhouse gas emissions and cost across food groups and processing levels offer opportunities for food swaps representing the healthiest, greenest, and most affordable options.

How Americans eat red and processed meat: an analysis of the contribution of thirteen different food groups

OBJECTIVE

Dietary patterns characterised by high intake of red and processed meat are associated with detrimental health and environmental outcomes. To better understand how Americans consume red and processed meat, this study examined the food groups that are the greatest contributors to red and processed meat intake in US diets.

DESIGN

Cross-sectional analysis of total red and processed meat, unprocessed red meat and processed meat using data from the National Health and Nutrition Examination Survey (2015-2016 and 2017-2018). Items containing red or processed meat were classified into thirteen mutually exclusive food groups. For highly consumed food groups (≥10 % of meat intake), contribution to meat intake was further assessed by source, sex, income and education.

SETTING

Nationally representative sample of the US population.

PARTICIPANTS

Teens (aged 12-19 years) and adults (aged ≥20 years) who reported meat consumption (n 8178).

RESULTS

Meat mixed dishes (18·6 % (95 % CI 16·2, 20·9)), burgers (17·3 % (95 % CI 15·3, 19·3)) and beef excluding ground (17·0 % (95 % CI 13·8, 20·1)) were the top contributors to unprocessed red meat intake. For processed meat, four food groups made up about four-fifths of total intake: cold cuts and cured meats (37·7 % (95 % CI 34·6, 40·8)), sausages and frankfurters (20·3 % (95 % CI 18·6, 22·0)), bacon (14·0 % (95 % CI 12·3, 15·6)) and pizza (10·1 % (95 % CI 8·7, 11·5)). Fast-food restaurants were the top source for burgers and pizza, whereas stores were the top source for all other highly consumed food groups. Few differences were seen in patterns of intake by sociodemographic characteristics.

CONCLUSIONS

No single food group accounts for a majority of meat intake in the USA. Many behaviour change opportunities for healthier, more sustainable substitutions exist.

Advantages and limitations of the methodological approaches used to study dietary shifts towards improved nutrition and sustainability

Acting on diet is one of the changes required - in combination with actions on food production, transformation, and waste - to address the challenges of reducing the environmental impact of our food systems and eliminating all forms of malnutrition. The number of studies exploring how to move towards a more sustainable diet has exploded over the past decades, but there is a need to facilitate their understanding and use by policy makers and all other stakeholders possibly influencing diet sustainability. The aim of the present article is to propose a categorization of studies into 4 approaches, based on the type of methodology used to explore diet sustainability, and to highlight the principles, advantages, and limitations of each approach in order to help study users in their interpretation. The 4 approaches are: assessment of sustainability characteristics of hypothetical diets (approach 1) or existing diets (approach 2), identification of existing "positive deviants" (approach 3), and design of more sustainable diets with constrained optimization (approach 4). Specificities and key findings drawn from each approach are described, and challenges for future studies are discussed.

Single-item substitutions can substantially reduce the carbon and water scarcity footprints of US diets

BACKGROUND

Human food systems substantially affect the environment, but the impacts vary widely by food. Guidance to individuals to reduce their dietary impacts would benefit from easy advice, but little is known about the specific population impacts of simple changes on self-selected diets.

OBJECTIVES

The objective was to estimate the potential impact of a single dietary substitution on the carbon and water scarcity footprints of self-selected diets in the United States.

METHODS

This cross-sectional modeling study used 24-h dietary recall data from the 2005-2010 waves of the NHANES. Greenhouse gas emissions (GHGE) in the production of foods as well as irrigated water use, characterized by its relative scarcity at production locations, were matched to all foods in the recalls using previously developed databases. Impacts were summed to create carbon and water scarcity footprints for diets (n  = 16,800) of adults aged >18 y. Diet quality was assessed using the Healthy Eating Index (HEI). Foods with the highest impact on GHGE and selected additional foods were substituted for calorically equivalent, less impactful items. Footprints were calculated before and after these hypothetical substitutions.

RESULTS

The highest impact foods were all beef items, and 19.8% of individuals consumed them (n = 3320). After substitution of these items with poultry or pork, the mean carbon and water scarcity footprints among those with substitutions significantly decreased (P < 0.001) by 48.4 ± 0.6% and 29.9 ± 0.4%, respectively. Across the entire sample, these represented mean reductions of 9.6 ± 0.3% and 5.9 ± 0.2%, respectively. The mean HEI after substitutions was 3.6 ± 0.1% higher than before (P < 0.001). None of the selected additional foods had population impacts as large as the beef substitutions.

CONCLUSIONS

Simple substitutions can be made in individuals' diets to substantially reduce their carbon and water scarcity footprints without sacrificing dietary quality. Such substitutions may be easier to promote than complex dietary patterns.

Cooking at Home, Fast Food, Meat Consumption, and Dietary Carbon Footprint among US Adults

Shifting consumer behavior towards more sustainable diets can benefit environmental sustainability and human health. Although more frequent home cooking is associated with a better diet quality and fast-food consumption with worse diet quality, the environmental impact of diets based on frequency of cooking or eating fast food is not well understood. The objective of this study was to investigate whether the frequency of cooking dinner at home or eating fast food is associated with dietary greenhouse gas emissions (GHGE). We linked 24-h dietary recall data from adult respondents in the 2007-2010 National Health and Nutrition Examination Survey (NHANES) (N = 11,469) to a database of GHGE factors to obtain a measure of dietary GHGE (kgCO2-eq/2000 kcal) (the sum of emissions released in the production of food for an individual's diet), adjusted by energy intake (kgCO2-eq/2000 kcal). We examined associations between frequency of cooking dinner (the only meal for which cooking frequency was measured), frequency of eating fast food, and dietary GHGE and protein sources (beef, pork, poultry, other meat, and fish and seafood (g/2000 kcal)) using generalized linearized regression models that controlled for age, sex, and other socio-economic characteristics. Greater cooking frequency was associated with higher dietary GHGE. In fully adjusted models, cooking 5-6 times/week was associated with an additional 0.058 kgCO2-eq/2000 kcal (SE 0.033) and cooking 7 times/week was associated with an additional 0.057 kgCO2-eq/2000 kcal (SE 0.027) when compared to cooking 0-2 times/week. Individuals in households who cooked dinner more frequently consumed significantly more meat, poultry, and fish (cooking 7 times/week: 148.7 g/2000 kcal vs. cooking 0-2 times/week: 135.4 g/2000 kcal, p-trend = 0.005), which could explain the association with a higher carbon footprint diet. There were few associations of note between fast-food frequency and GHGE. Policies and interventions that reduce consumption of meat and increase consumption of plants when both cooking meals at home and eating meals out are needed to shift toward diets that will be beneficial for both human health and the health of the planet.

Large-Scale Microanalysis of U.S. Household Food Carbon Footprints and Reduction Potentials

Promoting sustainable food consumption is critical to meet the United Nation's Sustainable Development Goals. The existing research using average diets and the individual one-day diet recall data to obtain insights into food carbon footprints (CFs) may neglect the diverse food purchasing patterns in different households (HHs). In this paper, we analyzed detailed grocery shopping records of 57,578 U.S. HHs to evaluate the associated food CFs. The cradle-to-farm-gate CFs of 83 food items were calculated using a process-based life cycle assessment model adapted to the U.S. condition. Using the CF of a healthy and sustainable diet as the benchmark, we quantified the CF reduction potentials for each HH. Our results suggest three key strategies to reduce HH food CFs: (1) lowering the over-purchasing in small (one- or two-person) HHs can achieve two-thirds of the recognized carbon emission reduction potentials; (2) reducing the intake of snacks, ready-made food, and drinks leads to as much as, if not more, carbon emission reduction than changing diets; and (3) more attention needs to be paid to reduce the carbon intensity of food items with large purchased volume.

Shifts towards healthy diets in the US can reduce environmental impacts but would be unaffordable for poorer minorities

Environmental implications of food choice are the focus of increasingly extensive research, but less is known about the impacts of dietary patterns of different socio-economic groups of a country, and the trade-offs between nutritional quality and environmental impacts of diet within those groups. We evaluate the impacts of US household dietary patterns on greenhouse gas emissions, blue water footprint, land use and energy consumption across supply chains using an environmentally extended input-output analysis. We compare the nutritional quality of these dietary patterns using healthy eating index scores across individuals' income and other socio-economic characteristics. Individuals with higher income or education levels are more likely to adopt healthier diets but are also responsible for larger environmental impacts of diet primarily due to a higher consumption of dairy and livestock products, seafood and items with lower energy density but higher nutrient density. Our optimization shows that a healthy diet with lower environmental impacts is achievable within current food budgets for almost 95% of people, and results in average decreases of 2% in food-related greenhouse gas emissions, 24% in land use and 4% in energy consumption, but a 28% increase in blue water consumption. However, such dietary patterns are unaffordable for 38% of Black and Hispanic individuals in the lowest income and education groups. Policies that affect income and food prices making nutritious food more affordable would be needed to achieve better nutrition and improved environmental outcomes simultaneously, particularly for more vulnerable socio-economic groups.

Data Integration for Diet Sustainability Analyses

Diet sustainability analyses are stronger when they incorporate multiple food systems domains, disciplines, scales, and time/space dimensions into a common modeling framework. Few analyses do this well: there are large gaps in food systems data in many regions, accessing private and some public data can be difficult, and there are analytical challenges, such as creating linkages across datasets and using complex analytical methods. This article summarizes key data sources across multiple domains of food system sustainability (nutrition, economic, environment) and describes methods and tools for integrating them into a common analytic framework. Our focus is the United States because of the large number of publicly available and highly disaggregated datasets. Thematically, we focus on linkages that exist between environmental and economic datasets to nutrition, which can be used to estimate the cost and agricultural resource use of food waste, interrelationships between healthy eating and climate impacts, diets optimized for cost, nutrition, and environmental impacts, and others. The limitations of these approaches and data sources are described next. By enhancing data integration across these fields, researchers can be better equipped to promote policy for sustainable diets.

Estimating the economic consequences of substance use and substance use disorders

INTRODUCTION

This contribution gives an overview on estimating the economic impact of substance use (SU) and substance use disorders (SUDs) from a societal perspective.

AREAS COVERED

In this Expert Review, we first discuss the scope of the economic costs of SU to society and the methods used to estimate them. In general, cost studies should not be limited to SUDs, but should also include costs related to the consequences of any type of SU to achieve a comprehensive picture of the societal burden. Further, estimating potentially avoidable costs will increase the value of cost studies. Importantly, methodologically sound cost studies shed light on the magnitude of societal problems related to SU and can be used as a reference point to evaluate regulatory policies and other preventive measures. The area of estimating potential economic benefits of SU is understudied and lacks a theoretical and methodological framework.

EXPERT OPINION

Overall, economic studies on the impact of SU and SUDs can strongly contribute to better-informed decision-making in the creation of regulatory and control policies. The least developed area of research refers to a consensus methodology that could be used in studies which compare economic costs to potential economic benefits.

Individual US diets show wide variation in water scarcity footprints

Agriculture accounts for 80% of global freshwater consumption but the environmental impacts of water use are highly localized and depend on water scarcity. The water use impacts of food production should be a key consideration of sustainable diets, yet little is known of the water scarcity demands of diets, especially of individuals. Here we estimate the water scarcity footprint (WSF)-a water use impact metric that accounts for regional scarcity-of individual diets in the United States (n = 16,800) and find a fivefold variation between the highest and lowest quintile of diets ranked by WSF. Larger intakes of some meat, fruit, nuts and vegetables drive these differences. Meat consumption is the greatest contributor (31%) to the WSF of the average diet, and within that, beef contributes about six times that of chicken. Variation between substitutable foods provides insight into diet shifts that can reduce WSF. We introduce a novel, geospatially explicit approach that combines the types and quantities of foods in the diets of individuals, the irrigation water required to produce those foods and the relative scarcity of water where that irrigation occurs.

The carbon footprint of dietary guidelines around the world: a seven country modeling study

Background

Do the environmental impacts inherent in national food-based dietary guidelines (FBDG) vary around the world, and, if so, how? Most previous studies that consider this question focus on a single country or compare countries’ guidelines without controlling for differences in country-level consumption patterns. To address this gap, we model the carbon footprint of the dietary guidelines from seven different countries, examine the key contributors to this, and control for consumption differences between countries.

Methods

In this purposive sample, we obtained FBDG from national sources for Germany, India, the Netherlands, Oman, Thailand, Uruguay, and the United States. These were used to structure recommended diets using 6 food groups: protein foods, dairy, grains, fruits, vegetables, and oils/fats. To determine specific quantities of individual foods within these groups, we used data on food supplies available for human consumption for each country from the UN Food and Agriculture Organization’s food balance sheets. The greenhouse gas emissions (GHGE) used to produce the foods in these consumption patterns were linked from our own database, constructed from an exhaustive review of the life cycle assessment literature. All guidelines were scaled to a 2000-kcal diet.

Results

Daily recommended amounts of dairy foods ranged from a low of 118 ml/d for Oman to a high of 710 ml/d for the US. The GHGE associated with these two recommendations were 0.17 and 1.10 kg CO₂-eq/d, respectively. The GHGE associated with the protein food recommendations ranged from 0.03 kg CO₂-eq/d in India  to 1.84 kg CO₂-eq/d in the US, for recommended amounts of 75 g/d and 156 g/d, respectively. Overall, US recommendations had the highest carbon footprint at 3.83 kg CO₂-eq/d, 4.5 times that of the recommended diet for India, which had the smallest footprint. After controlling for country-level consumption patterns by applying the US consumption pattern to all countries, US recommendations were still the highest, 19% and 47% higher than those of the Netherlands and Germany, respectively.

Conclusions

Despite our common human biology, FBDG vary tremendously from one country to the next, as do the associated carbon footprints of these guidelines. Understanding the carbon footprints of different recommendations can assist in future decision-making to incorporate environmental sustainability in dietary guidance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00669-6.

Healthy diets can create environmental trade-offs, depending on how diet quality is measured

Background

There is an urgent need to assess the linkages between diet patterns and environmental sustainability in order to meet global targets for reducing premature mortality and improving sustainable management of natural resources. This study fills an important research gap by evaluating the relationship between incremental differences in diet quality and multiple environmental burdens, while also accounting for the separate contributions of retail losses, inedible portions, and consumer waste.

Methods

Cross sectional, nationally-representative data on food intake in the United States were acquired from the National Health and Nutrition Examination Survey (2005–2016), and were linked with nationally-representative data on food loss and waste from published literature. Survey-weighted procedures estimated daily per capita food retail loss, food waste, inedible portions, and consumed food, and were summed to represent Total Food Demand. Diet quality was measured using the Healthy Eating Index-2015 and the Alternative Healthy Eating Index-2010. Data on food intake, loss, and waste were inputted into the US Foodprint Model to estimate the amount of agricultural land, fertilizer nutrients, pesticides, and irrigation water used to produce food.

Results

This study included dietary data from 50,014 individuals aged ≥2 y. Higher diet quality (HEI-2015 and AHEI-2010) was associated with greater per capita Total Food Demand, as well as greater retail loss, inedible portions, consumer waste, and consumed food (P < 0.001 for all comparisons). Consumed food accounted for 56–74% of agricultural resource use (land, fertilizer nutrients, pesticides, and irrigation water), retail loss accounted for 4–6%, inedible portions accounted for 2–15%, and consumer waste accounted for 20–23%. Higher diet quality was associated with lower use of agricultural land, but the relationship to other agricultural resources was dependent on the tool used to measure diet quality (HEI-2015 vs. AHEI-2010).

Conclusions

Over one-quarter of the agricultural inputs used to produce Total Food Demand were attributable to edible food that was not consumed. Importantly, this study also demonstrates that the relationship between diet quality and environmental sustainability depends on how diet quality is measured. These findings have implications for the development of sustainable dietary guidelines, which requires balancing population-level nutritional needs with the environmental impacts of food choices.

The Climate and Nutritional Impact of Beef in Different Dietary Patterns in Denmark

There is public focus on the environmental impact, and in particular, the emissions of greenhouse gases (GHG), related to our food consumption. The aim of the present study was to estimate the carbon footprint (CF), land use and nutritional impact of the different beef products ready to eat in different real-life dietary patterns. Beef products accounted for 513, 560, 409 and 1023 g CO₂eq per day, respectively, in the four dietary patterns (Traditional, Fast-food, Green, and High-beef). The total CFs of these diets were 4.4, 4.2, 4.3 and 5.0 kg CO₂eq per day (10 MJ)_, respectively. The Green diet had almost the same CF as the Traditional and the Fast-food diets despite having the lowest intake of beef as well as the lowest intake of red meat in total. A theoretical substitution of beef with other animal products or legumes in each of these three diets reduced the diets' CF by 4-12% and land use by 5-14%. As regards nutrients, both positive and negative impacts of these substitutions were found but only a few of particular nutritional importance, indicating that replacing beef with a combination of other foods without a significant effect on the nutrient profile of the diet is a potential mitigation option.