Food-related Greenhouse Gas Research Articles

Diet Impact Assessment model: an interactive tool for analysing the health, environmental and affordability implications of diets

Abstract Global diets, environmental factors, and health require a holistic approach in public health discourse that takes into account the well-being of both humans and planetary health. Modeling tools have demonstrated being useful to estimate priorities and differences between countries and gain insight into future paths that depend on predetermined priorities. Modeling efforts that include environmental goals indicate the possibility of reducing environmental impacts while both improving food quality and overall health outcomes, especially in high-income settings. The aforementioned forecasts highlight the effectiveness of giving priority to dietary recommendations that lead to better, balanced patterns as the most effective approach to reducing mortality risks and environmental implications. The presentation will introduce the Diet Impact Assessment (DIA) model - a new interactive modelling tool for analysing the health, environmental and affordability implications of diets and dietary change. The tool enables countries to analyse user-specific scenarios of dietary change, and to estimate the health, environmental and cost burden of each scenario in terms of diet costs, avoidable deaths, changes in resource use and compatibility with global environmental targets, including those associated with food-related greenhouse gas emissions, land use, water use and fertilizer application. The tool was commissioned by the WHO Regional Office for Europe and is based on analytical frameworks developed by Marco Springmann and colleagues.

A multi-dimensional Sustainable Diet Index (SDI) for Ghanaian adults under transition: the RODAM Study

BackgroundThe sustainability of diets consumed by African populations under socio-economic transition remains to be determined. This study developed and characterized a multi-dimensional Sustainable Diet Index (SDI) reflecting healthfulness, climate-friendliness, sociocultural benefits, and financial affordability using individual-level data of adults in rural and urban Ghana and Ghanaian migrants in Europe to identify the role of living environment in dietary sustainability.MethodsWe used cross-sectional data from the multi-centre Research on Obesity and Diabetes among African Migrants Study (N = 3169; age range: 25–70 years). For the SDI construct (0–16 score points), we used the Diet Quality Index-International, food-related greenhouse gas emission, the ratio of natural to processed foods, and the proportion of food expenditure from income. In linear regression analyses, we estimated the adjusted ß-coefficients and 95% confidence intervals (CIs) for the differences in mean SDI across study sites (using rural Ghana as a reference), accounting for sociodemographic and lifestyle factors.ResultsThe overall mean SDI was 8.0 (95% CI: 7.9, 8.1). Participants in the highest SDI-quintile compared to lower quintiles were older, more often women, non-smokers, and alcohol abstainers. The highest mean SDI was seen in London (9.1; 95% CI: 8.9, 9.3), followed by rural Ghana (8.2; 95% CI: 8.0, 8.3), Amsterdam (7.9; 95% CI: 7.7, 8.1), Berlin (7.8; 95% CI: 7.6, 8.0), and urban Ghana (7.7; 95% CI: 7.5, 7.8). Compared to rural Ghana, the differences between study sites were attenuated after accounting for age, gender and energy intake. No further changes were observed after adjustment for lifestyle factors.ConclusionThe multi-dimensional SDI describes four dimensions of dietary sustainability in this Ghanaian population. Our findings suggest that living in Europe improved dietary sustainability, but the opposite seems true for urbanization in Ghana.

Perspectives on healthcare decarbonization through plant-rich dietary shifts: cases from the US, Austria and Taiwan

The reduction of meat consumption in health systems is a high-impact pathway for healthcare decarbonization. Effects including changes in greenhouse gas emissions are rarely calculated following interventions, such as the implementation of plant-forward menus in hospitals, and the results of these changes are rarely published in peer-reviewed literature. In this perspective, we discuss the decarbonization outcomes of plant-rich dietary shifts across five health systems worldwide, gathered from peer-reviewed and gray literature. In each case, the implementation of a plant-rich approach reduced food-related greenhouse gas emissions. Health co-benefits are also commonly reported. The measurement of greenhouse gas emissions of plant-rich dietary shifts in future health system interventions is encouraged, with the results published in peer-reviewed journals.

Evaluating Food Procurement against the EAT-Lancet Planetary Health Diet in a Sample of U.S. Universities.

Aligning institutional food procurement with planetary health targets offers opportunities to improve nutrition and reduce food-related greenhouse gas (GHG) emissions. This study compared foods procured by 19 university dining programs in the U.S. in 2022 with the EAT-Lancet planetary health diet. Each university's procurement was then modeled to align with the EAT-Lancet planetary health diet, and changes to Healthy Eating Index (HEI) scores and GHG emissions were evaluated. For a subset of universities that provided cost data, changes in annual total food costs were also estimated. Universities in this study exceeded EAT-Lancet planetary health targets for beef (x- = 657% of target), pork (x- = 587%), poultry (x- = 379%), and eggs (x- = 293%). All universities failed to achieve planetary health targets for legumes and nuts (x- = 39% of the target) and vegetables (x- = 68%). Aligning food procurement with the planetary health diet would result in an estimated average 46.1% reduction in GHG emissions and a 19.7 point increase in HEI scores. Universities that provided cost data saw an average 9.7% reduction in food costs in the EAT-Lancet-aligned scenario. The procurement metrics assessed in this study can help university dining programs and other institutional food service organizations set goals and monitor progress toward planetary health targets.

Effects of a cafeteria-based sustainable diet intervention on the adherence to the EAT-Lancet planetary health diet and greenhouse gas emissions of consumers: a quasi-experimental study at a large German hospital

SummaryBackgroundSustainable diets contribute to improving human health and reducing food-related greenhouse gas emissions (GHGE). Here, we established the effects of a facility-based sustainable diet intervention on the adherence to the EAT-Lancet Planetary Health Diet and GHGE of consumers.MethodsIn this quasi-experiment, vegan menus and educational material on sustainable diets were provided in the largest cafeteria of a German hospital for 3 months. Regular customers (> 1/week) in this cafeteria (intervention group) and in all other hospital cafeterias (control group) completed a questionnaire about their sociodemographic and dietary characteristics before and after the intervention period. We calculated difference-in-differences (DID), their 95% confidence intervals (CIs), and p-values for the adherence to the EAT-Lancet Planetary Health Diet Index (PHDI; 0–42 score points) and food-related GHGE. The protocol was registered at the German Clinical Trial Register (reference: DRKS00032620).FindingsIn this study population (N = 190; age range: 18–79 years; women: 67%; highest level of formal education: 63%), the mean baseline PHDI (25·1 ± 4·8 vs. 24·7 ± 5·8 points) and the mean baseline GHGE (3·3 ± 0·8 vs. 3·3 ± 0·7 kg CO2-eq./d) were similar between the intervention (n = 92) and the control group (n = 98). The PHDI increase was 0·6 points (95% CI: -0·4, + 1·6) higher in the intervention group than in the control group. This trend was stronger among frequent consumers of the vegan menu than among rare and never consumers. No between-group difference was seen for GHGE changes (DID: 0·0; 95% CI: -0·2, + 0·1 kg CO2-eq./d).InterpretationPending verification in a longer-term project and a larger sample, this quasi-experiment in a big hospital in Germany suggests that offering vegan menus and information material in the cafeteria enhances the adherence to healthy and environmentally friendly diets among regular customers. These findings argue for making sustainable food choices the default option and for improving nutrition literacy.FundingFederal Ministry of Economic Affairs and Climate Action (BMWK), Else-Kröner-Fresenius Foundation (EKFS), Robert-Bosch Foundation (RBS).

Guiding people to take less food from the buffet: Two survey experiments that introduce a new simulated buffet scenario

Reducing portion sizes, has great potential to reduce food intake and plate waste. At all-you-can-eat buffets people tend to take larger portions of food than they would at home or at a general restaurant. Increased portion sizes can lead to people leaving uneaten food behind – contributing to food-related greenhouse gas emissions. This study develops and evaluates, in two online experiments, a meal guidance intervention to assist consumers with their meal choices. To measure behavioural intentions, we created a simulated buffet scenario where participants see a range of food items (as they would at a buffet) and are then asked to choose which foods and how many portions of each food item they would take. Compared to a control group, offering meal guidance did not appear to significantly decrease the number of grams or calories taken from the simulated buffet. However, there were significant differences in the number of grams and calories taken from the buffet when comparing those who at least followed the guidance in some way, and those who did not. Our research has methodological implications: it presents a novel and easy to implement measure of hypothetical buffet food choices and portioning that can be used in survey experiments. Future research could focus on developing strategies to prompt guests to follow meal guidance.

Better social infrastructure matters: Impacts of perceptional and behavioral smartization on food-related household emissions and wastes

Japan has been implementing policies to reduce greenhouse gas emissions (NDC goal) and food-related wastes (Food Recycling Act). However, these policies were mainly targeting commercial stakeholders instead of households. In this paper, we proposed a smart food transition framework with multiple dimensions, conducted a large sample size survey (5500 households in Japan) with consumer attitudes towards smart food services and smart eating habits, and investigated what may affect food-related household greenhouse gas emissions and food waste through a detailed assessment of both direct and indirect emissions. We found that, in the context of a better social infrastructure (e.g., better telecommunications infrastructure or higher penetration of SNS) where households can have a higher level of welfare and better access to smart food services, additional food waste would be generated, but not necessarily food-related greenhouse gas emissions. This is possible to be improved by perceptional changes and behavioral changes (e.g., more tolerance of using commercially prepared dishes, more willingness to use inventory management APPs). Our paper emphasized the importance of appropriate guidance in such perceptional changes and behavioral changes, together with detailed directions, for more decent household lives in the future of Japan.

Limiting red meat availability in a university food service setting reduces food-related greenhouse gas emissions by one-third

Limiting red meat availability in a university food service setting reduces food-related greenhouse gas emissions by one-third

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

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. 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. 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. 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. 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.

Application of the Automated Self-Administered 24-Hour (ASA24) Dietary Assessment Tool’s New Carbon Footprint Dataset

ObjectivesIncreasing concern about the environmental impacts of food production has motivated the development of a new dataset of food-related greenhouse gas emissions (GHGE). The dataset integrates with the Automated Self-Administered (ASA24) Dietary Assessment Tool, a popular web-based tool used by researchers. This paper aims to demonstrate the utility of this dataset by assessing the GHGE, or carbon footprint, of a menu from a consumer education program. MethodsThree days of a sample menu (breakfast, lunch, dinner, and snack) from the University of New Hampshire’s Extension program were entered into ASA24. The menu was based on a balanced food pattern with a range of protein sources, including meat and fish. The database of Food Recall Impacts on the Environment for Nutrition and Dietary Studies (dataFRIENDS) was linked, by food code, with the ASA24-2020 items output file. Matches were found for all items except eight spices. Total calories and CO2 equivalents were calculated by meal and day, based on the weight of each food item. Healthy Eating Index (HEI) total and component scores were estimated for each day. Documentation of the development of GHGE data for ASA24 foods and how to use them will be located on NCI’s ASA24 website. ResultsFor the three days, total kcal were 1612,2168, and 1666, and dietary GHGE were 2.2, 3.4, and 3.2 kg CO2-eq. The third day included two types of meat: ground beef, which contributed 40.7% of that day’s carbon footprint; and a turkey patty, which contributed 3.4%. HEI scores for the three days were 94.0, 83.3, and 89.0, varying inversely with dietary GHGE. The day with the largest carbon footprint had the highest total protein component score, yet the lowest seafood and plant protein score. The opposite was true for the day with the smallest carbon footprint. ConclusionsThis paper demonstrates the application of dataFRIENDS, a new resource for ASA24 users to examine dietary carbon footprints and inform the literature on the environmental impact of food choices. The database can be used to examine menus and dietary intake data, and to compare dietary GHGE with diet quality metrics, which may affect individual food choices. Further analyses can provide context for policies regarding sustainability for federal dietary guidance. Funding SourcesNone.

Public meals as a platform for culinary action? Tweens’ and teens’ acceptance of a new plant-based food

A plant-rich meal pattern is widely considered to be one possible solution for a shift towards a more sustainable food culture that considerably decreases food-related greenhouse gas emissions globally. The public meal, in particular school meals, can ideally become a platform for developing multisectoral cooperation through culinary action, transforming food from being a commodity to part of a strategic solution with societal outcomes. The aim of our study is to support a shift toward more sustainable meal solutions within the public meal sector. The objective is to introduce the check-all-that-apply (CATA) method in a large real-life consumer study, using only one food product, during a lunch break, and still account for the variation in perception between consumers. The objective is also to explore strategic multi-sectoral insights for introducing new foods to a larger population for a shift toward a plant-rich meal pattern. In this study, we established a cooperation between a small-sized food company, four schools and a university in Sweden. A plant-based sausage roll based on minced grey peas was developed. The likes and dislikes of 800 t(w)eens being served the grey pea roll were checked using hedonic values and CATA questions and compared with an ideal. To understand which CATA terms were persistent (meaning relevant, liked and just-about-right across consumer clusters), results including frequency scores, consistency, mean impact on liking, just-about-right scores and agglomerative hierarchical clustering were combined in an extended statistical processing. Our results show that unique/novel and natural were the only persistent CATA terms; these terms should therefore be interesting candidates for further improvement regarding classification and conceptualization of plant-based products in public meals. The CATA term vegetarian, on the other hand, can both increase and decrease liking scores.

Policy communication for health and sustainability: comparison of food-based dietary guidelines

Abstract Background Food-based dietary guidelines (FBDGs) provide advice on what constitutes a healthy diet, influencing both decision-making at the policy level, and educational programs addressed to consumers. There is a growing body of literature that allows to estimate the health and environmental impacts of the wide adoption of FBDG at the country and global levels. This unlocks the possibility of evaluating the most sustainable dietary guidelines from a communication perspective. This study aims at answering what are the key converging messages and main differences in the communication of FBDG that have a high environmental potential, and what of those FBDG do communicate a sustainability purpose in an explicit way. Methods A mixed-method comparative review of FBDGs with a two-stage sampling process was developed. Building on Springmann et al (2020) we identified the countries where the wide population adoption of dietary guidelines would have the highest potential of reducing food-related greenhouse gas emissions (GHGe) while delivering positive health outcomes. In a second stage, a purposeful sample of FBDGs was designed to cover countries from different WHO regions, income levels, and languages. Results This study is in progress and results are preliminary. Out of the initial sample of identified FBDG with a GHGe reduction potential of more than 25 percent, a few of them, Germany, Brazil, Sweden, Netherlands, and France had been previously identified in the literature as having sustainability-based recommendations. Other guidelines with similar GHGe reduction potential, such as those of Switzerland and Italy also address sustainability in an explicit way. Conclusions FBDGs have been traditionally focused on health and nutrition messages. Several countries have updated recommendations considering the environmental impacts of food consumption. Not all the FBDG with a high environmental potential explicitly communicate sustainability concerns. Key messages Several countries can improve their health and climate change outcomes by promoting a wider adoption of their official dietary guidelines. Communication is a key aspect of this process.

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.

Demand drivers and changes in food-related emissions in the UK: A decomposition approach

UK food-related greenhouse gas emissions have substantially decreased over the last two decades in response to changes in the household food baskets. The evolution of diets depends on a combination of driving forces, not necessarily acting in the same direction. We propose a decomposition of household food choices which separates changes in tastes and consumer preferences from the effects of prices, household budgets, and socio-demographic trends. More specifically, we explore to what extent these drivers facilitate or hinder the adoption of sustainable food choices. Our decomposition strategy is grounded on a theory-consistent demand system to account for substitution effects across food groups. We find that the decline in UK food-related emissions is primarily driven by reductions in household food budgets and evolving food preferences. Relative price dynamics and demographic trends act in the opposite direction, but their effect is small. Our evidence suggests that policy interventions aiming to shape consumer preferences towards more sustainable choices could be a valid instrument to further reduce food-related emissions in the UK.

Halving food-related greenhouse gas emissions can be achieved by redistributing meat consumption: Progressive optimization results of the NutriNet-Santé cohort

BackgroundDiet-related greenhouse gas emissions (GHGe) mainly comes from animal-sourced foods. As progressive changes are more acceptable for a sustainable food transition, we aimed to identify nutritionally adequate and culturally acceptable optimized diets ensuring a gradual reduction in GHGe, using observed diet from a large sample of French adults, while considering the mode of food production (organic vs conventional farming) and the co-production link between milk and beef. Material and methodBased on the consumption of 257 organic and conventional foods among 29,413 participants (75% women, age: 53.5 ± 14.0y) of the NutriNet-Santé study, we modelled optimal diets according to GHGe reduction scenarios in 5% steps, from 0 to 50% with nutritional, acceptability, and coproduct constraints, for men, premenopausal and menopausal women separately. ResultsGradual GHGe decrease under these constraints led to optimal diets with an overall decrease in animal foods, with marked reductions in dairy products (up to −83%), together with a stable but largely redistributed meat consumption in favor of poultry (up to +182%) and pork (up to +46%) and at the expense of ruminant meat (down to −92%). Amounts of legumes increases dramatically (up to +238%). The greater the reduction in diet-related GHGe, the lower the cumulative energy demand (about −25%) and land use (about −43%). The proportion of organic food increased from ~30% in the observed diets to ~70% in the optimized diets. ConclusionOur results suggest that meeting both nutrient reference value and environmental objectives of up to 50% GHGe reduction requires the reduction of animal foods together with important substitutions between animal food groups, which result in drastic reductions in beef and dairy products. Further research is required to explore alignment with long-term health value and conflict with acceptability, in particular for even greater GHGe reductions.

Impacts of home cooking methods and appliances on the GHG emissions of food.

Food is widely acknowledged as a major contributor to climate change but estimates of food-related greenhouse gas (GHG) emissions frequently consider supply chain stages only up to the farm gate or regional distribution centres. Here we estimate GHG emissions associated with different cooking methods and appliances in the UK. Data on current cooking practices were collected through a survey with more than 700 respondents. Our results reveal that home cooking accounts for as much as 61% of total emissions associated with specific foods, and that this can be substantially reduced through alternative, readily available cooking practices.

Sustainable and acceptable school meals through optimization analysis: an intervention study

BackgroundSchool meals hold considerable potential to shape children’s diets and reduce food-related greenhouse gas emissions (GHGE)—in the short and long term. This study applied linear optimization to develop a GHGE-reduced, nutritionally adequate, and affordable school lunch menu. The effects on food waste, consumption and pupils’ satisfaction with the meals were evaluated.MethodsA pre-post design was employed to assess the effects of implementing an optimized lunch menu on daily food waste, consumption, and pupils’ school meal satisfaction in three schools (grades 0–9) from one Swedish municipality. A food list containing amounts, prices, nutrient content, and GHGE-values of all foods used for a previously served (baseline) four-week lunch menu was created. Using linear programming, this food list was optimized for minimum deviation and constrained to ensure nutritional adequacy and a reduced climate impact. The optimized food list was developed into a new (intervention) four-week lunch menu by a professional meal planner, following the baseline menu as closely as possible. The baseline and intervention menus were served for four weeks, respectively, with a two week break in between. Prepared, wasted and leftover food were weighed daily by the school kitchen staff during both periods. Interrupted time series analysis assessed mean and slope differences in daily food waste and consumption between the two periods. School lunch satisfaction was assessed with an online questionnaire at baseline and during the intervention.ResultsOptimization resulted in a food list that was 40% lower in GHGE, met all nutrient recommendations for school meals, and cost 11% less compared to baseline. The intervention menu was served as planned, with only minor changes required (for practical reasons). Plate waste, serving waste, consumption and school lunch satisfaction did not differ significantly from baseline, in any of the schools.ConclusionsThe findings demonstrate that school meals can successfully be improved regarding health and environmental sustainability using linear optimization, without negative effects on food waste, consumption or cost. This approach offers the necessary flexibility to tailor menus towards different priorities and could therefore be transferred to other types of meal services.Trial registrationThe trial is registered at clinicaltrials.gov (NCT04168632 Fostering Healthy and Sustainable Diets Through School Meals (OPTIMAT).

Cool Food Collective Greenhouse Gas Emissions Baseline and 2030 Reduction Target

Cool Food is a global initiative that helps dining facilities commit to a science-based target to reduce their food-related greenhouse gas (GHG) emissions by 25 percent by 2030 relative to 2015. This paper establishes the baseline estimate for Cool Food members’ collective food-related GHG emissions and also reports the group’s 2030 reduction target. In total, members reported more than 129,000 tonnes (t) of food purchased in the base year. If members met the collective 25 percent GHG emissions reduction target, their actions would reduce the group’s annual emissions by more than 1,071,000 t CO2e per year by 2030 relative to the base year—a reduction equivalent to avoiding the annual tailpipe emissions from more than 230,000 passenger vehicles. We will provide a progress update using the group’s 2019 food purchase data once new data are available.

Adjusting food practices to climate prescriptions: vegetable gardening as a way to reduce food-related greenhouse gas emissions

During a survey of an experiment that involved using “carbon calculators”, we investigated what people think and what they do when they consider the link between their food and the climate. To what extent do individuals adhere to or reject the “prescriptions” implicitly contained in carbon calculators and passed on by environmental social movements or the authorities. These prescriptions are considered as recommendations or advice drawn up by experts aiming to guide behaviours; they involve reducing reality in a measuring device against which behaviours are gauged (in this case, the quantity of greenhouse gases). Three main levers are envisaged so that households can reduce their food’s impact on the climate: reducing the consumption of meat, eating local and eating in-season produce. However, in opposition to this conception of individuals as rational and free to adapt their practices based on the information available to them, we suggest an analytic framework that takes into consideration the fact that food and eating is embedded in everyday and social relationships. Calculating one’s greenhouse gas emissions (GGE) provokes an intense moment of reflexivity during which routines are called into question and discrepancies between prescriptions and practices emerge. Drawing our inspiration from, on the one hand, the theory of practice, we examine how the prescriptions are connected to practices, and on the other, using a pragmatic approach, we analyse how individuals call into question their food practices to resolve the contradictions they identify, and devise adjustments. We show how people appraise the context globally, which leads them to subvert the logic of the calculator or address the prescriptions more broadly to lend value to other practices to which they attach importance and consider adapted. This enabled us to highlight vegetable gardening and promoting eating locally produced food as favoured adjustments. The qualitative approach allows us to emphasise how the measuring device, rather than supplying a behaviourist model, makes it possible to render more visible the forms of attachment and categories of judgement mobilised, which do not obey strict accounting logics or a formal, narrow rationality, and to examine “what counts when you’re counting”.

Nudging to reduce meat consumption: Immediate and persistent effects of an intervention at a university restaurant

Reducing meat consumption is considered to have great potential to mitigate food-related greenhouse gas (GHG) emissions. I conducted a field experiment with two restaurants to test if nudging can increase the consumption of vegetarian food. At the treated restaurant, the salience of the vegetarian option was increased by changing the menu order and enhancing the visibility of the vegetarian dish. The other restaurant served as a control. Daily sales data on the three main dishes sold were collected from September 2015 until June 2016. Results show that the nudge increased the share of vegetarian lunches sold by on average 6 percentage points, and that the treatment effect increased over time. The change in behavior is partly persistent, as the share of vegetarian lunches sold remained 4 percentage points higher after the intervention ended than before the experiment. The intervention reduced GHG emissions from food sales by around 5 percent.