Table 2.
Results of hypothetical meat reductions among potential changers in dietary GHGE, Healthy Eating Index, and dietary costs
|
Food-related GHGE (kg CO2-equivalents per person per day)* |
Estimated Healthy Eating Index* |
Estimated diet cost (US$ per person per day)* |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Mean | Mean change† | Change (%)‡ | Mean | Mean change† | Change (%)‡ | Mean | Mean change† | Change (%)‡ | ||
| Original diet | 3·88 (3·64 to 4·12) | .. | .. | 52·65 (51·97 to 53·32) | .. | .. | 5·24 (5·16 to 5·32) | .. | .. | |
| 100% beef replaced | ||||||||||
| With poultry | 2·50 (2·36 to 2·64) | −1·38 (−1·58 to −1·19) | −35·7 | 53·53 (52·82 to 54·24) | 0·88 (0·76 to 1·00) | 1·7 | 5·15 (5·08 to 5·22) | −0·09 (−0·10 to −0·08) | −1·7 | |
| With plant protein§ | 2·32 (2·18 to 2·46) | −1·56 (−1·79 to −1·34) | −40·3 | 54·39 (53·64 to 55·14) | 1·74 (1·40 to 2·08) | 3·3 | 4·95 (4·87 to 5·03) | −0·29 (−0·33 to −0·25) | −5·5 | |
| 50% beef replaced | ||||||||||
| With poultry | 3·19 (3·03 to 3·35) | −0·69 (−0·79 to −0·59) | −17·8 | 53·09 (52·40 to 53·77) | 0·44 (0·38 to 0·50) | 0·8 | 5·20 (5·12 to 5·27) | −0·05 (−0·05 to −0·04) | −0·9 | |
| With plant protein§ | 3·10 (2·94 to 3·26) | −0·78 (−0·89 to −0·67) | −20·1 | 53·52 (52·82 to 54·22) | 0·87 (0·70 to 1·04) | 1·7 | 5·10 (5·02 to 5·17) | −0·14 (−0·17 to −0·12) | −2·8 | |
| 25% beef replaced | ||||||||||
| With poultry | 3·54 (3·34 to 3·74) | −0·35 (−0·40 to −0·30) | −8·9 | 52·87 (52·19 to 53·55) | 0·22 (0·19 to 0·25) | 0·4 | 5·22 (5·14 to 5·29) | −0·02 (−0·03 to −0·02) | −0·4 | |
| With plant protein§ | 3·49 (3·29 to 3·69) | −0·39 (−0·45 to −0·34) | −10·1 | 53·08 (52·40 to 53·77) | 0·44 (0·35 to 0·52) | 0·8 | 5·17 (5·09 to 5·25) | −0·07 (−0·08 to −0·06) | −1·4 | |
| 100% beef, pork, or poultry replaced with plant protein§ | 1·96 (1·84 to 2·08) | −1·93 (−2·14 to −1·71) | −49·6 | 57·22 (56·20 to 58·23) | 4·57 (4·04 to 5·09) | 8·7 | 4·69 (4·56 to 4·81) | −0·55 (−0·59 to −0·51) | −10·5 | |
| 50% beef, pork, or poultry replaced with plant protein§ | 2·92 (2·76 to 3·08) | −0·96 (−1·07 to −0·86) | −24·8 | 54·93 (54·15 to 55·71) | 2·28 (2·02 to 2·55) | 4·3 | 4·96 (4·87 to 5·06) | −0·28 (−0·30 to −0·26) | −5·3 | |
| 25% beef, pork, or poultry replaced with plant protein§ | 3·41 (3·21 to 3·61) | −0·48 (−0·54 to −0·43) | −12·1 | 53·79 (53·08 to 54·50) | 1·14 (1·01 to 1·27) | 2·2 | 5·10 (5·02 to 5·19) | −0·14 (−0·15 to −0·13) | −2·6 | |
Data are mean (95% CI); all analyses account for survey design and sampling weights. Potential changers (n=1026) are individuals who reported trying dietary guidance and were estimated to be likely to agree that humans contribute to climate change; these individuals comprised 16% (95% CI 15–17) of the sample. All replacements were made in equal calorie amounts, as estimated from the National Nutrient Database for Standard Reference. Replacements were only made if individuals consumed the meats in question: 645 (61%) ate beef and 938 (92%) ate beef, pork, or poultry; however, mean changes included all potential changers, whether a replacement was made or not. GHGE=greenhouse gas emissions. NHANES=US National Health and Nutrition Examination Survey.
Food-related GHGE were calculated on the basis of commodity intakes by use of the database of Food Impacts on the Environment for Linking to Diets; mean results are based on calculations of substitutions at the individual level, with variability due to sampling error in NHANES; HEI and diet cost results are means of person-level predicted values and associated CIs; predictions were based on commodity intakes and sociodemographic variables (appendix p 5).
A paired t test was used to test the hypothesis that the mean difference between individuals' substituted diets and original diets was equal to 0; all differences in the table were significant at a level of p<0·0001.
Values are percent change in the mean value compared with that of baseline (original).
Plant proteins are legumes, nuts, and seeds; diet changes for each potential changer reflected the individual's actual reported intakes of these three food groups; replacements were made in the same ratio as that the individual reported eating the three food groups; if the individual did not eat any of the food groups, the overall average ratio in the sample was used to distribute the new intake, specifically 0·405 for legumes other than soy, 0·336 for nuts or seeds, and 0·259 for soy.