Climate change mitigation and health effects of varied dietary patterns in real-life settings throughout North America

Environmental and nutrition impact of achieving new School Food Plan recommendations in the primary school meals sector in England

OBJECTIVES

The aim of this modelling study was to estimate the expected changes in the nutritional quality and greenhouse gas emissions (GHGEs) of primary school meals due to the adoption of new mandatory food-based standards for school meals.

SETTING

Nationally representative random sample of 136 primary schools in England was selected for the Primary School Food Survey (PSFS) with 50% response rate.

PARTICIPANTS

A sample of 6690 primary students from PSFS who consumed school meals.

OUTCOME MEASURES

Primary School Food Plan (SFP) nutritional impact was assessed using both macronutrient and micronutrient quality. The environmental impact was measured by GHGEs.

METHODS

The scenario tested was one in which every meal served in schools met more than half of the food-based standards mentioned in the SFP (SFP scenario). We used findings from a systematic review to assign GHGE values for each food item in the data set. The GHGE value and nutritional quality of SFP scenario meals was compared with the average primary school meal in the total PSFS data set (pre-SFP scenario). Prior to introduction of the SFP (pre-SFP scenario), the primary school meals had mandatory nutrient-based guidelines.

RESULTS

The percentage of meals that met the protein standard increased in the SFP scenario and the proportion of meals that met the standards for important micronutrients (eg, iron, calcium, vitamin A and C) also increased. However, the SFP scenario did not improve the salt, saturated fat and free sugar levels. The mean GHGE value of meals which met the SFP standards was 0.79 (95% CI 0.77 to 0.81) kgCO₂e compared with a mean value of 0.72 (0.71 to 0.74) kgCO₂e for all meals. Adopting the SFP would increase the total emissions associated with primary school meals by 22 000 000 kgCO₂e per year.

CONCLUSIONS

The universal adoption of the new food-based standards, without reformulation would result in an increase in the GHGEs of school meals and improve some aspects of the nutritional quality, but it would not improve the average salt, sugar and saturated fat content levels.

Decreasing the overall environmental impact of the Dutch diet: how to find healthy and sustainable diets with limited changes

OBJECTIVE

To find diets optimised on nutrition and environmental impact close to the current Dutch diet and to identify the most effective and acceptable options for mitigating environmental impact.

DESIGN

Linear programming was used to optimise diets of Dutch men and women aged 9-69 years, divided into ten age-gender groups. The analysis included nutrient composition, a metric for popularity and life cycle assessments of 207 food products. Greenhouse gas emissions, fossil energy use and land occupation were used to calculate a weighted score for the overall environmental impact. Optimised diets were solutions that minimised changes to the current diet while satisfying all nutritional constraints, with stepwise reductions in environmental impact.

SETTING

The Netherlands.

SUBJECTS

Dutch children and adults aged 9-69 years.

RESULTS

Meat was always reduced. Vegetable, fruit and dairy contents remained similar, while bread, fatty fish and legumes increased. The extent of changes depended on age and gender. Beverages were not heavily reduced. Nutrients critical for the outcome were α-linoleic acid, retinol, Ca, Na, Se, dietary fibre, SFA, thiamin and Fe (women of childbearing age). Total protein, essential amino acids and carbohydrates were not critical.

CONCLUSIONS

Reducing meat is the most effective option for lowering the environmental impact of diets in all age-gender groups. Reducing alcoholic and non-alcoholic beverages is another option. Leaving out fish and dairy products are not. The differences in nutritional requirements related to age and gender have a significant effect on the composition of the optimised diets.

The Impacts of Dietary Change on Greenhouse Gas Emissions, Land Use, Water Use, and Health: A Systematic Review

Food production is a major driver of greenhouse gas (GHG) emissions, water and land use, and dietary risk factors are contributors to non-communicable diseases. Shifts in dietary patterns can therefore potentially provide benefits for both the environment and health. However, there is uncertainty about the magnitude of these impacts, and the dietary changes necessary to achieve them. We systematically review the evidence on changes in GHG emissions, land use, and water use, from shifting current dietary intakes to environmentally sustainable dietary patterns. We find 14 common sustainable dietary patterns across reviewed studies, with reductions as high as 70–80% of GHG emissions and land use, and 50% of water use (with medians of about 20–30% for these indicators across all studies) possible by adopting sustainable dietary patterns. Reductions in environmental footprints were generally proportional to the magnitude of animal-based food restriction. Dietary shifts also yielded modest benefits in all-cause mortality risk. Our review reveals that environmental and health benefits are possible by shifting current Western diets to a variety of more sustainable dietary patterns.

Alignment of Healthy Dietary Patterns and Environmental Sustainability: A Systematic Review

To support food security for current and future generations, there is a need to understand the relation between sustainable diets and the health of a population. In recent years, a number of studies have investigated and compared different dietary patterns to better understand which foods and eating patterns have less of an environmental impact while meeting nutritional needs and promoting health. This systematic review (SR) of population-level dietary patterns and food sustainability extends and updates the SR that was conducted by the 2015 US Dietary Guidelines Advisory Committee, an expert committee commissioned by the federal government to inform dietary guidance as it relates to the committee's original conclusions. In the original SR, 15 studies met the criteria for inclusion; since then, an additional 8 studies have been identified and included. The relations between dietary intake patterns and both health and environmental outcomes were compared across studies, with methodologies that included modeling, life cycle assessment, and land use analysis. Across studies, consistent evidence indicated that a dietary pattern higher in plant-based foods (e.g., vegetables, fruits, legumes, seeds, nuts, whole grains) and lower in animal-based foods (especially red meat), as well as lower in total energy, is both healthier and associated with a lesser impact on the environment. This dietary pattern differs from current average consumption patterns in the United States. Our updated SR confirms and strengthens the conclusions of the original US Dietary Guidelines Advisory Committee SR, which found that adherence to several well-characterized dietary patterns, including vegetarian (with variations) diets, dietary guidelines-related diets, Mediterranean-style diets, the Dietary Approaches to Stop Hypertension (DASH) diet, and other sustainable diet scenarios, promotes greater health and has a less negative impact on the environment than current average dietary intakes.

Mindful Climate Action: Health and Environmental Co-Benefits from Mindfulness-Based Behavioral Training

Greenhouse gases from human activities are causing climate change, creating risks for people around the globe. Behaviors involving transportation, diet, energy use, and purchasing drive greenhouse gas emissions, but are also related to health and well-being, providing opportunity for co-benefits. Replacing shorter automobile trips with walking or cycling, or eating plants rather than animals, for example, may increase personal health, while also reducing environmental impact. Mindfulness-based practices have been shown to enhance a variety of health outcomes, but have not been adapted towards environmental purposes. We designed the Mindful Climate Action (MCA) curriculum to help people improve their health while simultaneously lowering their carbon footprints. Combining mindfulness-based practices with the Stages of Change theory, the MCA program aims to: (1) improve personal health and well-being; (2) decrease energy use; (3) reduce automobile use; (4) increase active transport; (5) shift diet towards plant-based foods; and (6) reduce unnecessary purchasing. Mindfulness practices will foster attentional awareness, openness, and response flexibility, supporting positive behavior change. We plan to test MCA in a randomized controlled trial, with rigorous assessment of targeted outcomes. Our long-term goal is to refine and adapt the MCA program to a variety of audiences, in order to enhance public health and environmental sustainability.

A Systematic Review of the Measurement of Sustainable Diets

Sustainability has become an integral consideration of the dietary guidelines of many countries in recent decades. However, a lack of clear metrics and a shared approach to measuring the multiple components of sustainable diets has hindered progress toward generating the evidence needed to ensure the credibility of new guidelines. We performed a systematic literature review of empirical research studies on sustainable diets to identify the components of sustainability that were measured and the methods applied to do so. Two independent reviewers systematically searched 30 databases and other sources with the use of a uniform set of search terms and a priori exclusion criteria. In total, 113 empirical studies were included in the final review. Nearly all of the studies were focused on high-income countries. Although there was substantial heterogeneity in the components of sustainability measured, the estimated greenhouse gas emissions (GHGEs) of various dietary patterns were by far most commonly measured (n = 71 studies). Estimating the GHGEs of foods through various stages of production, use, and recycling with the use of the Life Cycle Assessment approach was the most common method applied to measure the environmental impacts of diets (n = 49 studies). Many components of sustainable diets identified in existing conceptual frameworks are disproportionately underrepresented in the empirical literature, as are studies that examine consumer demand for sustainable dietary alternatives. The emphasis in the literature on high-income countries also overlooks the production and dietary alternatives most relevant to low- and middle-income countries. We propose 3 methodological and measurement approaches that would both improve the global relevance of our understanding of sustainable diets and attend more completely to the existing multidimensional, multiscale conceptual framing of sustainable diets.

Environmental Nutrition: A New Frontier for Public Health

Food systems must operate within environmental constraints to avoid disastrous consequences for the biosphere. Such constraints must also take into account nutritional quality and health outcomes. Given the intrinsic relationships between the environmental sciences and nutritional sciences, it is imperative that public health embraces environmental nutrition as the new frontier of research and practice and begins a concerted focus on the new discipline of environmental nutrition, which seeks to comprehensively address the sustainability of food systems. We provide an overview to justify our proposition, outline a research and practice agenda for environmental nutrition, and explore how the complex relationships within food systems that affect public health could be better understood through the environmental nutrition model.

How to Build a Standardized Country-Specific Environmental Food Database for Nutritional Epidemiology Studies

There is a lack of standardized country-specific environmental data to combine with nutritional and dietary data for assessing the environmental impact of individual diets in epidemiology surveys, which are consequently reliant on environmental food datasets based on values retrieved from a heterogeneous literature. The aim of this study was to compare and assess the relative strengths and limits of a database of food greenhouse gas emissions (GHGE) values estimated with a hybrid method combining input/output and LCA approaches, with a dataset of GHGE values retrieved from the literature. France is the geographical perimeter considered in this study, but the methodology could be applied to other countries. The GHGE of 402 foodstuffs, representative of French diet, were estimated using the hybrid method. In parallel, the GHGE of individual foods were collected from existing literature. Median per-food-category GHGE values from the hybrid method and the reviewed literature were found to correlate strongly (Spearman correlation was 0.83), showing similar rankings of food categories. Median values were significantly different for only 5 (out of 29) food categories, including the ruminant meats category for which the hybrid method gave lower estimates than those from existing literature. Analysis also revealed that literature values came from heterogeneous studies that were not always sourced and that were conducted under different LCA modeling hypotheses. In contrast, the hybrid method helps build reliably-sourced, representative national standards for product-based datasets. We anticipate this hybrid method to be a starting point for better environmental impact assessments of diets.

Do low-carbon-emission diets lead to higher nutritional quality and positive health outcomes? A systematic review of the literature

Objective

To evaluate what is known about the relative health impacts, in terms of nutrient intake and health outcomes, of diets with reduced greenhouse gas emissions (GHGE).

Design

We systematically reviewed the results of published studies that link GHGE of dietary patterns to nutritional content or associated consequences for health.

Setting

We included studies published in English in peer-reviewed journals that included data on actual and modelled diets and enabled a matched comparison of GHGE with nutrient composition and/or health outcomes.

Subjects

Studies included used data from subjects from the general population, who had taken part in dietary surveys or prospective cohort studies.

Results

We identified sixteen eligible studies, with data on 100 dietary patterns. We present the results as dietary links between GHGE reduction and impact on nutrients to limit (n 151), micronutrient content (n 158) and health outcomes (n 25). The results were highly heterogeneous. Across all measures of ‘healthiness’, 64 % (n 214) of dietary links show that reduced GHGE from diets were associated with worse health indicators. However, some trends emerged. In particular, reduced saturated fat and salt are often associated with reduced GHGE in diets that are low in animal products (57/84). Yet these diets are also often high in sugar (38/55) and low in essential micronutrients (129/158).

Conclusions

Dietary scenarios that have lower GHGE compared with average consumption patterns may not result in improvements in nutritional quality or health outcomes. Dietary recommendations for reduced GHGE must also address sugar consumption and micronutrient intake.

Diet-related greenhouse gas emissions assessed by a food frequency questionnaire and validated using 7-day weighed food records

BACKGROUND

The current food system generates about 25 % of total greenhouse gas emissions (GHGE), including deforestation, and thereby substantially contributes to the warming of the earth's surface. To understand the association between food and nutrient intake and GHGE, we therefore need valid methods to assess diet-related GHGE in observational studies.

METHODS

Life cycle assessment (LCA) studies assess the environmental impact of different food items. We linked LCA data expressed as kg carbon dioxide equivalents (CO2e) per kg food product to data on food intake assessed by the food frequency questionnaire (FFQ) Meal-Q and validated it against a 7-day weighed food record (WFR). 166 male and female volunteers aged 20-63 years completed Meal-Q and the WFR, and their food intake was linked to LCA data.

RESULTS

The mean GHGE assessed with Meal-Q was 3.76 kg CO2e per day and person, whereas it was 5.04 kg CO2e using the WFR. The energy-adjusted and deattenuated Pearson and Spearman correlation coefficients were 0.68 and 0.70, respectively. Moreover, compared to the WFR, Meal-Q provided a good ranking ability, with 90 % of the participants classified into the same or adjacent quartile according to their daily average CO2e. The Bland-Altman plot showed an acceptable level of agreement between the two methods and the reproducibility of Meal-Q was high.

CONCLUSIONS

This is the first study validating the assessment of diet-related GHGE by a questionnaire. The results suggest that Meal-Q is a useful tool for studying the link between food habits and CO2e in future epidemiological studies.

Eating like there's no tomorrow: Public awareness of the environmental impact of food and reluctance to eat less meat as part of a sustainable diet

Reducing meat consumption is central to many of the scientific debates on healthy, sustainable diets because of the high environmental impact of meat production. Missing from these debates are the public perspectives about eating less meat and consideration of cultural and social values associated with meat. The aim of this study was to explore public awareness of the environmental impact of food and their willingness to reduce meat consumption. Twelve focus groups and four individual interviews were conducted with adults from a range of socio-economic groups living in both rural and urban settings in Scotland. Public understanding of the link between food, environment and climate change was explored, with a focus on meat and attitudes towards reducing meat consumption. Data were transcribed and analysed thematically. Three dominant themes emerged: a lack of awareness of the association between meat consumption and climate change, perceptions of personal meat consumption playing a minimal role in the global context of climate change, and resistance to the idea of reducing personal meat consumption. People associated eating meat with pleasure, and described social, personal and cultural values around eating meat. Some people felt they did not need to eat less meat because they had already reduced their consumption or that they only ate small quantities. Scepticism of scientific evidence linking meat and climate change was common. Changing non-food related behaviours was viewed as more acceptable and a greater priority for climate change mitigation. The study highlights the role meat plays in the diet for many people, beyond nutritional needs. If healthy, sustainable dietary habits are to be achieved, cultural, social and personal values around eating meat must be integrated into the development of future dietary recommendations.

A Survey of Registered Dietitians' Concern and Actions Regarding Climate Change in the United States

Dietary choices are a tool to reduce greenhouse gas emissions. While registered dietitians are on the front lines of food and nutrition recommendations, it is unclear how many are concerned with climate change and take action in practice in the United States. We explored concern about climate change among registered dietitians, and identified factors that may influence practice-related behaviors. Our study population included a random sample of all registered dietitians credentialed in the United States. Primary data were gathered using a cross-sectional survey. Of the 570 survey responses, 75% strongly agreed or agreed that climate change is an important issue while 34% strongly agreed or agreed that dietitians should play a major role in climate change mitigation strategies. Thirty-eight percent engaged in activities that promoted diet as a climate change mitigation strategy. Vegetarian (p = 0.002) and vegan dietitians (p = 0.007) were significantly more likely than non-vegetarian and non-vegan dietitians to engage in activities that promoted diet as a climate change mitigation strategy. Overall, concern for climate change among dietitians varied significantly by the region of the country in which the dietitian resided, and awareness that animal products are implicated in climate change. Registered dietitians in the United States are concerned with climate change. However, there is a discrepancy between concern and practice-based actions. These results suggest the need for educational and experiential opportunities connecting climate change mitigation to dietetics practice.

Greater accordance with the Dietary Approaches to Stop Hypertension dietary pattern is associated with lower diet-related greenhouse gas production but higher dietary costs in the United Kingdom

BACKGROUND

The Dietary Approaches to Stop Hypertension (DASH) diet is a proven way to prevent and control hypertension and other chronic disease. Because the DASH diet emphasizes plant-based foods, including vegetables and grains, adhering to this diet might also bring about environmental benefits, including lower associated production of greenhouse gases (GHGs).

OBJECTIVE

The objective was to examine the interrelation between dietary accordance with the DASH diet and associated GHGs. A secondary aim was to examine the retail cost of diets by level of DASH accordance.

DESIGN

In this cross-sectional study of adults aged 39-79 y from the European Prospective Investigation into Cancer and Nutrition-Norfolk, United Kingdom cohort (n = 24,293), dietary intakes estimated from food-frequency questionnaires were analyzed for their accordance with the 8 DASH food and nutrient-based targets. Associations between DASH accordance, GHGs, and dietary costs were evaluated in regression analyses. Dietary GHGs were estimated with United Kingdom-specific data on carbon dioxide equivalents associated with commodities and foods. Dietary costs were estimated by using national food prices from a United Kingdom-based supermarket comparison website.

RESULTS

Greater accordance with the DASH dietary targets was associated with lower GHGs. Diets in the highest quintile of accordance had a GHG impact of 5.60 compared with 6.71 kg carbon dioxide equivalents/d for least-accordant diets (P < 0.0001). Among the DASH food groups, GHGs were most strongly and positively associated with meat consumption and negatively with whole-grain consumption. In addition, higher accordance with the DASH diet was associated with higher dietary costs, with the mean cost of diets in the top quintile of DASH scores 18% higher than that of diets in the lowest quintile (P < 0.0001).

CONCLUSIONS

Promoting wider uptake of the DASH diet in the United Kingdom may improve population health and reduce diet-related GHGs. However, to make the DASH diet more accessible, food affordability, particularly for lower income groups, will have to be addressed.

The Impacts of Climate Change Mitigation Strategies on Animal Welfare

The objective of this review is to point out that the global dialog on reducing greenhouse gas emissions in animal agriculture has, thus far, not adequately considered animal welfare in proposed climate change mitigation strategies. Many suggested approaches for reducing emissions, most of which could generally be described as calls for the intensification of production, can have substantial effects on the animals. Given the growing world-wide awareness and concern for animal welfare, many of these approaches are not socially sustainable. This review identifies the main emission abatement strategies in the climate change literature that would negatively affect animal welfare and details the associated problems. Alternative strategies are also identified as possible solutions for animal welfare and climate change, and it is suggested that more attention be focused on these types of options when allocating resources, researching mitigation strategies, and making policy decisions on reducing emissions from animal agriculture.

Comparing the water, energy, pesticide and fertilizer usage for the production of foods consumed by different dietary types in California

Objective

To compare the use of water, energy, pesticides and fertilizer to produce commodities for two dietary patterns that vary in the content of plant and animal products.

Design

A unique analysis using ‘real-world’ data was performed, in contrast to previous analyses which applied simulated data. Consumption data from the Adventist Health Study were used to identify two dietary patterns with a markedly different consumption of several plant and animal products. State agricultural data were collected and applied to commodity production statistics. Indices were created to allow a comparison of the resource requirements for each dietary pattern.

Setting

California, USA.

Subjects

None.

Results

The diet containing more animal products required an additional 10 252 litres of water, 9910 kJ of energy, 186 g of fertilizer and 6 g of pesticides per week in comparison to the diet containing less animal products. The greatest contribution to the difference came from the consumption of animal products, particularly beef.

Conclusions

Consuming a more plant-based diet could to an extent alleviate the negative environmental impacts related to food production. As a method to feed ourselves more sustainably, behavioural adjustments appear to be a very important tool.

Total Environmental Impact of Three Main Dietary Patterns in Relation to the Content of Animal and Plant Food

Based on a review of the most recent available scientific evidence, the new Dietary Guidelines for Americans 2010 (USDA DG) provide information and advice for choosing a healthy diet. To compare the environmental impacts of, respectively, omnivorous (OMN), lacto-ovo-vegetarian (LOV) and vegan (VEG) dietary patterns as suggested in the USDA DG, we analyzed the three patterns by Life Cycle Assessment (LCA) methodology. The presence of animal food in the diet was the main determinant of environmental impact. The major impact always stemmed from land and water use. The second largest impact came from energy use. Emission of toxic inorganic compounds into the atmosphere was the third cause of impact. Climate change and acidification/eutrophication represented other substantial impacts.

Sustainability of plant-based diets: back to the future

Plant-based diets in comparison to diets rich in animal products are more sustainable because they use many fewer natural resources and are less taxing on the environment. Given the global population explosion and increase in wealth, there is an increased demand for foods of animal origin. Environmental data are rapidly accumulating on the unsustainability of current worldwide food consumption practices that are high in meat and dairy products. Natural nonrenewable resources are becoming scarce, and environmental degradation is rapidly increasing. At the current trends of food consumption and environmental changes, food security and food sustainability are on a collision course. Changing course (to avoid the collision) will require extreme downward shifts in meat and dairy consumption by large segments of the world's population. Other approaches such as food waste reduction and precision agriculture and/or other technological advances have to be simultaneously pursued; however, they are insufficient to make the global food system sustainable. For millennia, meatless diets have been advocated on the basis of values, and large segments of the world population have thrived on plant-based diets. "Going back" to plant-based diets worldwide seems to be a reasonable alternative for a sustainable future. Policies in favor of the global adoption of plant-based diets will simultaneously optimize the food supply, health, environmental, and social justice outcomes for the world's population. Implementing such nutrition policy is perhaps one of the most rational and moral paths for a sustainable future of the human race and other living creatures of the biosphere that we share.