Another study on obesity & Africans, with a slight twist, Admixture Mapping of Obesity-related Traits in African Americans: The Atherosclerosis Risk in Communities (ARIC) Study:
Obesity is an important cause of morbidity and mortality worldwide. In the United States, the prevalence of obesity is higher in African Americans than whites, even after adjustment for socioeconomic status (SES). This leads to the hypothesis that differences in genetic background may contribute to racial/ethnic differences in obesity-related traits. We tested this hypothesis by conducting a genome-wide admixture mapping scan using 1,350 ancestry-informative single-nucleotide polymorphisms (SNPs) in 3,531 self-identified blacks from the Atherosclerosis Risk in Communities (ARIC) study. We used these markers to estimate the overall proportions of European ancestry (PEAs) for each individual and then scanned for the association between PEA and obesity-related traits (both continuous and dichotomous) at each locus. The median (interquartile range) PEA was 0.151 (0.115). PEA was inversely correlated with continuous BMI, weight, and subscapular skinfold thickness, even after adjusting for socioeconomic factors. In contrast, PEA was positively correlated with BMI-adjusted waist circumference....
BMI is a coarse measure. The positive correlation between European ancestry and waist circumference shows how genes can shape your body type, even if we're interested in only slices of information.
Citation: Obesity (2009) doi:10.1038/oby.2009.28
I wonder if we have a bad combo of environment and genes. I remember seeing a map of the US here that highlighted obesity among whites; the giant red areas were in the South. Given that 80% of African Americans live in those same areas and that sugar intake is much higher in the south than elsewhere, the genetic component may just be a secondary indicator of susceptibility to a particular environmental toxin.