Table A1.

People’s awareness of the environmental impact of meat production and consumption.

Title					Outcome Measure: Perceived Environmental Impact
Author(s), Year	Design; Year Data Collected	Country; Sample	Main Research Question	Provided Information Prior to the Experiment	Question or Dependent Variable	Response or Finding	Effect of Covariates
Campbell- Arvai, 2015 [29] *	Survey in dining halls; unspecified	U.S.; undergraduate students, convenience sample, N = 320, 46% men	Food-related environmental beliefs and behaviors	No info	(1) Eating less meat can help the environment. (2) Adopting a vegetarian diet can help the environment	(1) 29% agree; 20% unsure; 51% disagree (2) 22% agree; 13% unsure; 65% disagree Lowest level of agreement compared with other behaviors (e.g., using less packaging, grown locally)	n.a.
Clonan et al., 2015 [28] *	Postal survey; 2009	UK (Nottinghamshire); random sample from electoral registers, N = 842, 41% men	Meat consumption attitudes and sustainable meat purchase	No info	To help reduce the impact of climate change, it is better to eat less animal foods (meat, dairy products and eggs).	18% agree 46% unsure 36% disagree	Red and processed meat intake frequency, sustainable meat purchase frequency, gender, age, SES were not significant
Cordts et al., 2014 [25] *	Online experiment; 2013	Germany; quota sample, N = 590, 52% men	Consumer response to negative information on meat consumption	Variables measured before info provision (experimental manipulation)	(1) Farming animals and producing animal products (e.g., milk or meat) has a considerable negative environmental impact. (2) A vegetarian diet is more environmentally friendly than a diet including meat.	(1) M = 3.07, SD = 1.12 (1 = do not agree at all to 5 = fully agree) (2) M = 3.10, SD = 1.21 (1 = do not agree at all to 5 = fully agree)	(1) Women agreed more than men (M = 3.19; SD = 1.11; M = 2.95; SD = 1.12; p ≤ 0.01) (2) Women agreed more than men (M = 3.23; SD = 1.19, M = 2.98; SD = 1.21; p ≤ 0.05)
De Boer et al., 2016 [30]	Nation-wide consumer surveys; 2014	Netherlands and the USA; representative sample N = 527 (The Netherlands). Weighted variables: gender, age, level of education, region, and a value-related test score on “mentality-environment”. (efficiency of the weighting 89%, effective sample size 478) N = 556 (USA). Weighted variables: gender, age, and level of education (efficiency of the weighting 90%, effective sample size 500) Total = 1083	Consumer awareness of meat consumption environmental impact and their willingness to reduce meat consumption, among other research questions.	No prior info given.	“For each of the following lifestyle- changes, please let us know whether you think this is an effective way of combatting climate change”. The options, which were presented in randomized order, were: “Eat less meat”, “Buy local, seasonal, unprocessed foods (e.g., by going to farmer’s markets)”, “Buy (more) organic foods”, “Drive less”, “Save energy at home (e.g., turning thermostat down, using saving bulbs, air-drying laundry)”, and “Install solar panels on my house”.	Dutch: “eating less meat” option, second less effective 12% recognized the outstanding effectiveness of the less meat option in the eyes of climate experts 46% attributed effectiveness to the “eating less meat” option Americans: “eating less meat” option, the least effective 6% recognized the outstanding effectiveness of the less meat option in the eyes of climate experts 30% attributed effectiveness to the “eating less meat” option	Regular meat eaters assigned lower effectiveness ratings to the less meat and the organic food option, but not to the other options. Belief in human causation and personal importance were associated with assigning higher effectiveness ratings to all the options. The pattern of profile results remained unchanged when gender, age, and level of education were entered as covariates. The analysis revealed that these variables had small effects on the effectivity ratings. Females gave slightly higher ratings than males, especially to the food-related options
Study 1 de Boer, Schösler, et al., 2013 [20] *	Online survey; 2010	The Netherlands; quota sample, N = 1083, 50% men	Motivational explanations for responses to the meat-free meal idea	No info before questions	(1) Agriculture and animal husbandry together are one of the major causes of climate change. (2) If agriculture and animal husbandry change the way they work, they can counter climate change.	(1) 23% agree 36% unsure 41% disagree (2) 38% agree 37% unsure 25% disagree	n.a.
Study 2 de Boer et al., 2014 [31] *	Online survey; 2010	The Netherlands; quota sample, N = 1083, 50% men	Consumer strategies to reduce meat consumption and its’ association with their willingness to eat meatless meals	As an individual, you can make a big difference to nature and climate protection by choosing one (or more) meals without meat every week.	Did you know that?	64% yes, 36% no	More ‘yes’ responses for older and better educated people
De Groeve, et al., 2017 [21]	Online survey. Two samples. Data collected in 2015 (sample 1) and 2016 (sample 2)	Belgium; Ghent University Business Administration Students; N = 429	Assess students support for six less meat initiatives (LMIs) to be implemented in student restaurants.	No prior info given.	Students’ knowledge about the negative impact of meat on the environment	4.66% reported “Very much” 24.4% rather much 36.6% not little, not much 24.4% Little 9.79% Very little	n.a.
Graca, Oliveira, et al., 2015 [24] *	Online survey; 2013	Portugal; convenience sample, N = 410, 30% men	Multiple correspondence analysis to identify clusters of meat-related associations	Info provided after the question	Participants responded to an open ended question about how meat consumption may impact nature and the environment	24% pollutes nature and the environment; 20% erosion, disruption, depletion of natural resources; 18% references to mass production, artificial methods; 14% impacts only if unregulated or in excess; 11% does not impact nature and the environment;	n.a.
Lea & Worsley, 2008 [27] *	Postal survey; 2004	Australia (Victoria); random sample, N = 223, 48% men	Food-related environmental beliefs and behaviors	No info	Consumers eating less meat’ is important to help the environment	22% agree 22% unsure 56% disagree Lowest level of agreement compared with other behaviors (e.g., using less packaging, grown locally)	n.a.
Pohjolainen et al., 2016 [22]	Postal survey; 2010	Finland; representative sample. N = 1890	The level of environmental consciousness among Finnish consumers concerning meat production and consumption	No prior info given.	Participants had to agree or disagree with the following three statements: (1) meat production strengthens climate change significantly more than plant production (2) meat production causes eutrophication significantly more than plant production (3) food production causes significant environmental problems	(1) 35.7% agree; 47% neutral; 17.3% disagree (2) 34.8% agree; 45% neutral;20.2% disagree (3) 35.6% agree; 37.7% neutral; 26.7% disagree	Consumers clustered in six groups depending on their awareness of meat-related environmental questions: Those aware (highly conscious and rather conscious), those resistant to the idea (Resistant), those who give neutral answers (highly unsure and rather unsure) and those “careless conscious”. Among the groups highly and rather conscious, the majority is female (66.2% and 55.3%), two thirds aged between 46–75, 40% or more have tertiary education. When occupation is considered, in both groups more than 40% are not in labor force and blue-collar workers are slightly more represented than white-collar (26.1–21.1%/21.9–19.6%).
Tobler et al., 2011 [33] follow-up study by Siegrist et al., 2015 [32] *	Postal survey; longitudinal study: 2010, follow-up 2014	Switzerland (German- and French-speaking regions); random panel sample, N2010 = 6189, N2014 = 2781, 48% men	Consumer willingness to adopt ecological food consumption	No info	Perceived environmental benefit of eating less meat (maximum of once or twice per week), (1 = very small to 6 = very large)	M = 3.75, SD = 1.71, reducing meat consumption was perceived as having the lowest environmental effect compared with other behaviors (e.g., avoiding excessive packaging or organic food). Longitudinal study; Increase across time (M2010 = 3.89, SD = 1.69; M2014 = 4.23, SD = 1.56; p < 0.001)	Women perceived meat reduction as more beneficial for the environment than men (M = 3.96, SD = 1.69; M = 3.52, SD = 1.70; p < 0.001) Larger improvement for women and higher educated participants; p < 0.001
Truelove et al., 2012 [26]	Mixed methods. Online survey with open ended questions and behavior ratings.; 2008	USA; Undergraduate psychology majors (N = 112) (69 women and 43 men)	Students perceptions of the relative impact and effectiveness of certain behaviors on global warming.	No prior info given.	(1) Open-ended request to participants to list their own behaviors that cause global warming. (2) Respondents asked to rate the impact of 16 behaviors in contributing to GW. Rate went from 1 (Negligible impact) to 11 (Major impact). (3) Open-ended request to participants to list behaviors that reduce global warming. (4) Respondents asked to rate the impact of 20 behaviors that contribute to reduce GW. 1 (Extremely ineffective) to 11 (Extremely effective)	(1) Driving was mentioned by 90% participants. Eat meat only by less than 10% (2) Eat meat was rated with median of 3.83/11, just above behaviors like riding your bike and skiing. SD: 2.52 (3) Drive less and use alternate transportation was mentioned by almost 80% of the participants. Recycle by more than 45%. Reduce meat consumption by less than 5% (4) Reduce your meat consumption: 4.35/11 effectiveness. SD: 2.96	In answer (4), women scored higher than men.
Vanhonacker et al., 2013 [23] *	Online survey; 2011	Belgium (Flanders); convenience sample, N = 221, 36% men	Attitudes towards more sustainable food choices and consumer segmentation based on their self-evaluated ecological footprint	Explanation of the concept ‘ecological footprint’ Participants were informed about the contribution of animal production to Co2 emissions.	Participants had to score the contribution to greenhouse gas emissions for various industry sectors, including livestock production. Participants were asked how aware they were of the extent of this contribution.	Approx. M = 3.7 (no number, only bar chart presented) (1 = does not contribute at all to 5 = contributes very much) Livestock production was underestimated relative to other activities (e.g., transport, energy use) 58% reported awareness	n.a.

Notes n.a.: not assessed; M = arithmetic mean; SD = standard deviation; SES = socioeconomic status. *: As reported by [55].