TABLE 3.
Mean changes in environmental impacts after a single-item substitution among those with substitutions and for the entire sample1
| Environmental impact | Before substitution, mean ± SE | After substitution, mean ± SE | Absolute difference, mean ± SE | Percentage difference, mean ± SE | P value2 |
|---|---|---|---|---|---|
| For those with substitutions1 (n = 3320) | |||||
| Carbon footprint, kg CO2-eq 2000 kcal–1 | 7.23 ± 0.07 | 3.51 ± 0.04 | –3.73 ± 0.07 | –48.4 ± 0.6 | <0.001 |
| Water scarcity footprint, liter-eq 2000 kcal–1 | 3268 ± 45 | 2297 ± 38 | –972 ± 18 | –29.9 ± 0.4 | <0.001 |
| For the entire sample3 (n = 16,800) | |||||
| Carbon footprint, kg CO2-eq 2000 kcal–1 | 4.42 ± 0.03 | 3.68 ± 0.03 | –0.74 ± 0.03 | –9.6 ± 0.3 | <0.001 |
| Water scarcity footprint, liter-eq 2000 kcal–1 | 2542 ± 27 | 2349 ± 26 | –192 ± 7 | –5.9 ± 0.2 | <0.001 |
One single-item substitution was made for any individual that consumed one of the high-impact foods, either ground beef or a cut of beef, on his or her 24-h recall day. If the individual consumed the food more than once on that day, only 1 instance, the one with the highest carbon footprint, was substituted. See Supplementary Table 5 for the high-impact foods and their substitutions. kg CO2-eq, kilograms of carbon dioxide equivalents; liter-eq, liter-equivalent.
P value determined from a paired t test.
These results describe mean environmental impacts assessed for the entire sample, even though substitutions were only made on a subsample of 3320 individuals.