Obesity susceptibility loci and dietary intake in the Look AHEAD Trial

Background: Genome-wide association studies (GWAS) have identified consistent associations with obesity. However, the mechanisms remain unclear. Objective: The objective was to determine the association between obesity susceptibility loci and dietary intake. Design: The association of GWAS-identified obesity risk alleles (FTO, MC4R, SH2B1, BDNF, INSIG2, TNNI3K, NISCH-STAB1, MTIF3, MAP2K5, QPCTL/GIPR, and PPARG) with dietary intake, measured through food-frequency questionnaires, was investigated in 2075 participants from the Look AHEAD (Action for Health in Diabetes) clinical trial. We adjusted for age, sex, population stratification, and study site. Results: Obesity risk alleles at FTO rs1421085 significantly predicted more eating episodes per day (P = 0.001) an effect that persisted after adjustment for body weight (P = 0.004). Risk variants within BDNF were significantly associated with more servings from the dairy product and the meat, eggs, nuts, and beans food groups (P <= 0.004). The risk allele at SH2BI rs4788099 was significantly associated with more servings of dairy products (P = 0.001), whereas the risk allele at TNNI3K rs1514176 was significantly associated with a lower percentage of energy from protein (P = 0.002). Conclusion: These findings suggest that obesity risk loci may affect the pattern and content of food consumption among overweight or obese individuals with type 2 diabetes. The Look AHEAD Genetic Ancillary Study was registered at clinicaltrials.gov as NCT01270763 and the Look AHEAD study as NCT00017953. Am J Clin Nutr 2012;95:1477-86.