Food Quality and Preference, Volume 86, December 2020,
Research on the relationship between vegetarianism and subjective well-being (SWB) has produced inconsistent results, which may partly be due to small sample sizes and divergent operationalizations of well-being. For these reasons, the present study aimed to thoroughly examine this association in two large representative samples from Germany (Study 1: N = 12,905, including 665 vegetarians) and Australia (Study 2: N = 15,532, including 383 vegetarians) using a consensual conceptualization of SWB (composed of an affective component, i.e., positive and negative affect, and a cognitive component, i.e., life satisfaction). Results of t-tests showed that vegetarians reported slightly higher scores in negative affect (Study 1 and 2), but also slightly higher levels of satisfaction with health (Study 1 and 2) and life satisfaction (Study 1) compared to meat eaters. No differences emerged regarding positive affect in either study. These differences between vegetarians and meat-eaters in some components of SWB, although significant due to the large sample sizes, are small at best (d around 0.15). Because sex, age, and education were associated with diet type and SWB, analyses controlling for socio-demographic variables were also conducted. In these ANCOVAS, the effect of diet emerged only for one out of the five formerly significant comparisons (negative affect in Study 1, d = 0.09) while the differences between vegetarians and meat eaters in both satisfaction with health and life, as well as the effect on negative affect in Study 2, all became non-significant (d around 0.05). Taken together, the very small effects found in the t-tests for some components of SWB seem to be due to socio-demographic variables, meaning that the true effects of diet on SWB are non-existent or negligible.