The United States is not only the land of opportunity, but also the land of obesity. In 2000, approximately 16% of immigrants in the United States were obese, compared to 22% of native-born Americans. Immigrants eventually close in on native-born Americans, as longer duration in the United States is associated with greater obesity, and by the second generation, the obesity rates of immigrant children resemble other Americans.
Increasing obesity risk among longer-duration immigrants is yet another example of the so-called “healthy immigrant paradox.” Despite arriving with better health across several dimensions, immigrants appear to negatively assimilate and ultimately adopt the unhealthy behaviors of the receiving country. For obesity the usual suspects are a combination of sedentary behaviors, poor diet, and stress. More recent studies have proposed another intervening mechanism: racial discrimination.
In a fascinating 2008 study in the American Journal of Public Health, Gilbert Gee and colleagues examined the role of everyday discrimination in promoting weight gain among Asian immigrants. Respondents were asked how frequently they experience chronic and routine unfair treatment such as being called names, being treated with less courtesy, people acting afraid of them, and being threatened or harassed. They were then able to also specify what they believed the cause of discrimination was, so people could choose whether the discrimination was on the basis of weight, race, or something else.
Controlling for weight discrimination separately from racial discrimination, and also controlling for social desirability bias and other confounders, the authors found a substantial main effect of racial discrimination on weight. For a person with average values for each of the covariates, the probability of being obese among Asian immigrants was only 4.6% if the person did not report racial discrimination, but the probability doubled to 9.3% if discrimination was reported. (It’s worth noting that even for this group the rate of obesity falls well below the national average).
There are some plausible biological mechanisms that could explain the discrimination-obesity relationship: being discriminated against creates stress, and stress causes the production of glucocorticoids, which stimulate the appetite, and cortisol levels, which lead to greater abdominal weight gain.
Perhaps the most astounding finding from the AJPH study is depicted below:
Recent immigrants that report discrimination have a very similar body mass index to immigrants that do not report discrimination, but as the duration of stay in the United States steadily increases the body mass index increases for the discrimination group but remains constant for the no-discrimination group. Interpreted causally, this would imply that the stress of discrimination accumulates over time leading to steady weight gain.
The causal interpretation is difficult to conclusively establish, however, since the relationship is assessed using cross-sectional data rather than repeated measures on the same individuals. Another potential confounder that the authors cannot completely address is the contextual role of different food environments – places with higher levels of racism may also have fewer fresh foods available and more sedentary lifestyles, although these structural inequalities are not completely causally connected. The authors do control for large regions in the United States, but of course there is lots of variation at much smaller levels of geography. Finally, it is worth noting that not all studies of other immigrant groups and racial minorities find an effect of perceived discrimination on obesity, so the unique risk factors of Asian Americans are worth considering.
The problems of immigrant weight gain have garnered some attention, and efforts to promote access to fresh fruits and vegetables and provide better weight counseling have been increased. But the provocative question raised by this research is whether we need to think about interventions that are further upstream – including interventions to either alter racial attitudes or to promote better racial coping – as a way to improve the mental and behavioral health of immigrants.