Severe obesity, defined as body mass index (BMI) ≥ 40 kg/m2, is a rapidly growing public health issue already afflicting 8% of American adults (Flegal et al., 2016; NHLBI Expert Panel, 1998). Although present in less than 1% of the population in middle-income countries such as India and China, prevalence of severe obesity in these countries has increased more than 100-fold over the last three decades and shows no signs of slowing (NCD Risk Factor Collaboration, 2017). Individuals with severe obesity are often stigmatized due to the commonly-held belief that their condition results primarily from unhealthy lifestyle choices (Tomiyama et al., 2018). However, obesity is known to be heritable, suggesting that inborn DNA variation confers increased susceptibility in some individuals and protection in others (Elks et al., 2012; Maes et al., 1997; Whitaker et al., 1997; Yang et al., 2015).
