Environmental nudges to reduce meat demand
Authors: Donald Rose
Journal: The Lancet Planetary Health (2018)

Agriculture is a major contributor to environmental damage. Although substantial evidence indicates that a demand for less meat could significantly reduce the effects of diet on the environment,1Aleksandrowicz L Green R Joy EJ Smith P Haines A The impacts of dietary change on greenhouse gas emissions, land use, water use, and health: a systematic review.PLoS One. 2016; 11: e0165797Crossref PubMed Scopus (440) Google Scholar we know much less about how to achieve this goal. Changing dietary behaviour is difficult because individuals might not be motivated to change their habits or have the tools to do so, or there might be social pressures for them to maintain current eating patterns. Moreover, aspects of the physical microenvironments in which we live, such as worksites, schools, grocery stores, cafeterias, and restaurants, can affect our behaviour. For example, restaurant portion sizes can affect how much we eat. We might put more vegetables on our plate if they are placed at the beginning of a cafeteria line. An enticing verbal description of a meat-free menu item can increase the odds of its selection. These and other environmental influences on eating behaviour have been appreciated for some time in the fields of public health and behavioural economics.2Booth SL Sallis JF Ritenbaugh C et al.Environmental and societal factors affect food choice and physical activity: rationale, influences, and leverage points.Nutr Rev. 2001; 59: S21-S39Crossref PubMed Scopus (489) Google Scholar, 3Thaler RH Sunstein CR Nudge: improving decisions about health, wealth, and happiness. Yale University Press, New Haven, CT2008Google Scholar What do we know from the accumulated research about the effects of changing physical microenvironments to reduce meat demand? This question is addressed in a systematic review and qualitative comparative analysis by Filippo Bianchi and colleagues4Bianchi F Garnett E Dorsel C Aveyard P Jebb SA Restructuring physical micro-environments to reduce the demand for meat: a systematic review and qualitative comparative analysis.Lancet Planet Health. 2018; 2: e384-e397Summary Full Text Full Text PDF PubMed Scopus (72) Google Scholar in The Lancet Planetary Health. Bianchi and colleagues combed the literature—more than 10 000 articles—to find experimental evidence on the effects of environmental changes, categorised into availability, portion size, position, label, sensory properties, and price, on reducing meat demand (defined by the authors as consumption, purchase, or selection of meat in real or virtual environments). 14 articles describing 22 interventions met the inclusion criteria. Interventions most likely to succeed in reducing demand were those that reduced portion sizes, provided meat alternatives with accompanying educational material, or changed the sensory properties of meat and meat alternatives. Restructuring physical microenvironments is not the only way to reduce meat consumption. Consumer change can also be attempted through education or motivation. Unfortunately, studies of purely educational or motivational interventions to reduce meat consumption were not included in this review,4Bianchi F Garnett E Dorsel C Aveyard P Jebb SA Restructuring physical micro-environments to reduce the demand for meat: a systematic review and qualitative comparative analysis.Lancet Planet Health. 2018; 2: e384-e397Summary Full Text Full Text PDF PubMed Scopus (72) Google Scholar unless they also included components to restructure the environment. Some might find this inclusion criterion to be too restrictive because it precludes the possibility of jointly analysing the relative merits of educational, environmental, and combined educational and environmental interventions. Another concern is the use of the word meat in the review because it represents an overly aggregated category that could include meat from ruminant animals (beef and lamb), as well as pork and poultry. These meats differ substantially in their effects on health, as alluded to by the authors. Environmental differences are even more pronounced. For example, beef has about eight times the carbon footprint of chicken (33 kg vs 4 kg carbon dioxide equivalents per kg).5Heller MC Willits-Smith A Meyer R Keoleian GA Rose D Greenhouse gas emissions and energy use associated with production of individual self-selected US diets.Environ Res Lett. 2018; 13: 044004Crossref PubMed Scopus (96) Google Scholar The use of this terminology is a common problem, and is complicated by the differing nutritional and culinary definitions of meat and even red meat. For interventions to have the greatest effects on health and the environment, it will be helpful going forward to use more specific categorisations. The review appropriately focused on experimental studies, but observational studies can provide tremendous insight into the effects of large-scale policy changes on population-wide phenomena, such as demand change. This approach is particularly needed when analysing economic variables, such as prices. Bianchi and colleagues4Bianchi F Garnett E Dorsel C Aveyard P Jebb SA Restructuring physical micro-environments to reduce the demand for meat: a systematic review and qualitative comparative analysis.Lancet Planet Health. 2018; 2: e384-e397Summary Full Text Full Text PDF PubMed Scopus (72) Google Scholar found that evidence on the effects of price changes from randomised trials of reducing meat consumption was too limited to be conclusive. Although this finding is accurate in a narrow sense, it is broadly misleading. Thousands of studies from the field of consumer economics tell us that price matters and that when the price of a good goes up with all else equal, consumers will buy less of it. This well developed economic theory is based mostly on observational studies. However, it has been confirmed in studies aiming to improve nutritional outcomes by use of experimental evidence on vending machine snacks,6French SA Jeffery RW Story M et al.Pricing and promotion effects on low-fat vending snack purchases: the CHIPS study.Am J Public Health. 2001; 91: 112-117Crossref PubMed Scopus (384) Google Scholar natural experiments on taxation of sugar-sweetened beverages,7Colchero MA Popkin BM Rivera JA Ng SW Beverage purchases from stores in Mexico under the excise tax on sugar sweetened beverages: observational study.BMJ. 2016; 352: h6704Crossref PubMed Scopus (514) Google Scholar, 8Falbe J Thompson HR Becker CM Rojas N McCulloch CE Madsen KA Impact of the Berkeley excise tax on sugar-sweetened beverage consumption.Am J Public Health. 2016; 106: 1865-1871Crossref PubMed Scopus (284) Google Scholar and experimental evidence from grocery store interventions.9Hartmann-Boyce J Bianchi F Piernas C et al.Grocery store interventions to change food purchasing behaviors: a systematic review of randomized controlled trials.Am J Clin Nutr. 2018; 107: 1004-1016Crossref PubMed Scopus (96) Google Scholar This is not to say that experimental work on increasing meat prices is not warranted. Despite the substantial economics literature on meat demand, controversies still exist about conclusions based on econometric (ie, observational) studies. For example, the long-term decline in beef demand in the USA, which began in the 1970s, could be attributed to either a structural change in consumer preferences for healthier meats (ie, chicken), demographic changes, increased consumption of meals away from home, or simply increased prices as a result of supply changes.10Alston JM Chalfant JA Can we take the con out of meat demand studies?.Western Journal of Agricultural Economics. 1991; 16: 36-48Google Scholar, 11Eales JS Unnevehr LJ Simultaneity and structural change in US meat demand.Am J Agric Econ. 1993; 2: 259-268Crossref Scopus (81) Google Scholar More context-specific studies of meat demand, both experimental and observational, are needed to better understand where macro and micro policies can nudge consumers towards reducing their meat consumption. Given political considerations, some national policies, such as a carbon tax, might be difficult to implement. When national governments fail to act, policies enacted at the local level—either by local governments or private institutions—can lead the way for environmental change. In this regard, the review by Bianchi and colleagues is important because it provides a foundation for better understanding of how changes to physical microenvironments can help meet goals to reduce the environmental effects of meat in our diets. This work was supported by the Wellcome Trust (grant number 106854/Z/15/Z). Restructuring physical micro-environments to reduce the demand for meat: a systematic review and qualitative comparative analysisSome interventions restructuring physical micro-environments could help to promote lower demand for meat. Interventions reducing portion sizes of meat servings, providing meat alternatives, or changing the sensory properties of meat and meat alternatives at point of purchase offered the most promise in the context of experimental studies. Full-Text PDF Open Access