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

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.

Sustainable food systems under environmental footprints: The delicate balance from farm to table

In today's world, agriculture is not only about food production but also a critical factor in global environmental change, economic stability, and human health, among other aspects. With population growth and increasingly scarce resources, exploring sustainable development of food systems has become crucial. Achieving this goal requires striking a delicate balance among food security, economic development, ecological environment, and human health. Traditional approaches to sustainable agricultural development research often focus solely on singular domains, overlooking the inherent connections and interactions among environmental, socioeconomic, and health dimensions. This perspective limits our comprehensive understanding of food systems. Environmental footprint assessments can be integrated with economic, systemic, and decision models to analyze environmental, socioeconomic, and health issues within food systems. This integration accurately captures the diversity, overlap, accumulation, and heterogeneity of environmental pressures resulting from human and natural factors. Therefore, we propose an innovative conceptual framework that considers environmental, socioeconomic, and health dimensions as crucial components, with the environmental footprint indicators at its core, to link various stages from farm to table. This framework constructs an evidence gap map, integrating dispersed data and perspectives from existing literature, thus showing knowledge gaps across these domains. Such an interdisciplinary approach not only provides a more comprehensive perspective on the multidimensional complexity of sustainable food systems but also reveals potential synergies and conflicts among environmental, socioeconomic, and health domains, thereby guiding more comprehensive and cautious policy-making. Importantly, it provides direction for future research to achieve the sustainable development of food systems, emphasizing the necessity of a comprehensive, integrated research perspective, particularly in strengthening studies on composited footprints, viewing the entire farm-to-table continuum holistically. Stakeholders must collaborate and coordinate environmental, socioeconomic, and health objectives to drive the sustainable development of food systems.

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.

The Impact of Sustainability Courses: Are They Effective in Improving Diet Quality and Anthropometric Indices?

There are studies on the effect of general nutrition education on diet quality and anthropometric measurements, while studies showing the effectiveness of sustainable nutrition education, which also addresses the effect of food on the environment, are quite limited. This study aimed to investigate the effects of sustainable nutrition education on diet quality, anthropometric measurements, and the carbon footprint (CFP) and water footprint (WFP) of diet. A total of 160 university students received 1 h of sustainable nutrition education for 6 weeks. Before, at the end of, and 2 months after the courses, 24 h food consumption records were taken to assess diet quality and CFP and WFP values of diet, and Mediterranean diet (MedDiet) and Healthy Eating Index (HEI)-2020 scores were evaluated. The results of the study showed that sustainable nutrition education increased MedDiet score by 1.86 points and HEI-2020 score by 7.38 points. This education program also decreased body weight, body mass index (BMI), fat mass, and neck circumference. Sustainability education has a positive impact on calcium, potassium, and magnesium intakes, a negative impact on vitamin B12 and zinc intakes, and no effect on total protein intake. Education resulted in a 22% reduction in CFP and a 10% reduction in WFP.

Environmental-, Climate-, and Health-Related Dietary Motivations Are Associated With Higher Diet Quality in a National Sample of US Adults With Lower Incomes

BACKGROUND

Plant-based diets can have co-benefits for human and planetary health. Associations between environmental, climate, and health concerns and dietary intake in US adults are understudied, particularly in underserved populations.

OBJECTIVE

The study objectives were to assess how dietary choices motivated by the environment, climate, and health vary by sociodemographic characteristics and how they relate to diet quality and intake frequency of different food groups in US adults with lower incomes.

DESIGN

The study design was cross-sectional.

PARTICIPANTS/SETTING

A web-based survey was fielded in December 2022 to 1,798 US adults with lower incomes (<250% of federal poverty guidelines).

MAIN OUTCOME MEASURES

Environmental-, climate-, and health-related dietary motivations and diet quality and dietary food group intake frequency were assessed.

STATISTICAL ANALYSES

Differences in mean dietary outcomes and dietary motivation ratings by sociodemographic characteristics were evaluated using analysis of variance and Kruskal-Wallis tests. Associations between dietary motivations and diet quality scores and dietary intake frequency were examined using generalized linear models adjusted for sociodemographic covariates.

RESULTS

Younger adults, women, nonbinary people, racial and ethnic minoritized groups, and adults experiencing food insecurity reported higher environmental and climate dietary motivations; older adults, higher-income adults, and food-secure adults reported higher health motivations. Agreeing with environmental- (β = 2.28, 95% CI 1.09 to 3.47), climate- (β = 2.15, 95% CI 0.90 to 3.40), and health-related (β = 5.27, 95% CI 3.98 to 6.56) dietary motivations was associated with higher diet quality scores compared with those with neutral rankings. Similarly, agreement with environmental-, climate-, and health-related dietary motivations was associated with higher intake frequency of fish, fruits and vegetables, and plant proteins, but not with red and processed meat intake frequency. Of several climate-mitigation behaviors presented, participants perceived meat reduction as least effective (P < .001).

CONCLUSIONS

Environment, climate, and health were positive motivators of several healthy dietary choices in US adults with lower incomes. Such motivators did not translate to lower intake frequency of red and processed meat.

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.

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.

Consumption of foods with the highest nutritional quality, and the lowest greenhouse gas emissions and price, differs between socio-economic groups in the UK population

OBJECTIVE

To establish a baseline understanding of whether consuming food with the highest nutritional quality, lowest greenhouse gas emissions (GHGE) and cost differs between different UK demographic and socio-economic population groups.

DESIGN

Multiple linear regression models were fitted to evaluate the relationship between predictor socio-demographic variables in this study (i.e. sex, ethnic group, age, BMI and level of deprivation) and the response variables (i.e. consumption of items considered most nutritious, with a low GHGE and price, as a proportion of total items consumed).

SETTING

The UK.

PARTICIPANTS

1374 adult (18-65 years) participants from the National Diet and Nutrition Survey latest waves 9-11 (2016-2017 and 2018-2019).

RESULTS

Based on the total energy consumption in a day, the average diet-based GHGE was significantly higher for participants with a higher BMI. Non-white and most deprived participants spent significantly (P < 0·001) less money per total energy consumption. Participants with a BMI between 18·6 and 39·9 kg/m2 and those living in the least deprived areas consumed a significantly (P < 0·001) higher amount of those items considered the most nutritious, with the lowest GHGE and cost per 100 kcal.

CONCLUSIONS

Consumption of food with the highest nutritional quality, lowest GHGE and cost in the UK varies among those with different socio-demographic characteristics, especially the deprivation level of participants. Our analysis endorses the consideration of environmental sustainability and affordability, in addition to the consideration of nutritional quality from a health perspective, to make current dietary guidelines more encompassing and equitable.

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.

Current dietary intake of the Japanese population in reference to the planetary health diet-preliminary assessment

Introduction

We sought to assess the Japanese diet by examining the current dietary intake in Japan using the global reference diet from the EAT-Lancet Commission (Planetary Health Diet; PHD), from the perspective of protein intake in different age groups.

Methods

Average dietary intake by food group in the Japan National Health and Nutrition Survey 2019 (NHNS 2019) was converted to the PHD food groups, and the diet gap (DG) (%) of the global reference of the PHD was calculated by age group.

Results

Although the DG of the intake was excessive compared with the global reference of the PHD in most food groups in all age groups (7.1-416%), the intake exceeded the upper limit of the range only for red meat (640%). Red meat had the highest DG among subjects in their 40s, although the DG decreased with increasing age. Protein intake was within the possible range and did not greatly exceed the recommended dietary intake in the Japanese standard.

Discussion

The current Japanese diet contains an excessive intake of red meat in terms of the global reference of the PHD. This trend is similar to that previously reported in various western regions and countries. However, the Japanese diet does not significantly exceed the recommended protein intake for Japanese people, suggesting that the PHD is an environmentally friendly and healthy choice for younger and older age groups in an aging Japanese society. Policy makers need to develop sustainable and healthy food-based dietary guidelines in addition to providing food and nutrition education and developing a food environment that encourages sustainable and healthy choices to support dietary change.

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.

Food-Level Analysis to Identify Dietary Choices With the Highest Nutritional Quality and Lowest Greenhouse Gas Emissions and Price

Introduction

Food systems are challenged to provide healthy, sustainable and affordable foods. From a consumer perspective, identifying healthy, sustainable and affordable choices based on individual food products rather than diets could promote better shopping choices.

Objective

To identify foods and drinks with the highest nutritional quality and lowest greenhouse gas emissions (GHGE) and price. We also assessed how a combination of these indicators (e.g., nutritional quality, GHGE and price) for food categories aligned with current United Kingdom dietary recommendations.

Materials and Methods

We performed a secondary analysis of the National Diet and Nutrition Survey (NDNS) nutrient databank year 11 (2018/2019). Spearman correlation coefficients were used to assess the strength of relationships between nutritional quality, environmental impact and/or prices per 100 kcal. In addition, we developed an optimized nutritional quality, GHGE and price score for each food or drink item based on the overall medians for each of these indicators.

Results

Median nutritional value was highest for fruit and vegetables, whilst median GHGE and price was lower for starchy carbohydrates, fats and items of which consumption should be limited. The relative proportions of foods considered the most nutritious and with a low GHGE and price in each of the food categories, on a per 100 kcal basis, were comparable to the proportions in the Eatwell Guide, except for the proportion of fruits and vegetables being smaller and the proportion of potatoes, bread, rice, pasta, and other starchy carbohydrates being larger in our analysis.

Conclusion

Public health efforts should consider the impact of dietary choices not only in terms of nutritional quality but also in terms of environmental and economic impact. Our food-based analysis shows a large variation in nutritional quality, GHGE and price within and across food categories, which provides consumers with opportunities for "food swaps" that are more nutritious and have lower GHGE and price.