FTO genotype, dietary protein, and change in appetite: the Preventing Overweight Using Novel Dietary Strategies trial

Background: A common obesity-risk variant rs9939609 in the fat mass and obesity-associated (FTO) gene was recently shown to affect appetite, and the gene is sensitive to the regulation of amino acids. Objective: We examined the interaction between FTO genotype and protein intake on the long-term changes in appetite in a randomized controlled trial. Design: We genotyped FTO rs9939609 in 737 overweight adults in the 2-y Preventing Overweight Using Novel Dietary Strategies trial and assessed 4 appetite-related traits including cravings, fullness, hunger, and prospective consumption. Results: We showed that dietary protein significantly modified genetic effects on changes in food cravings and appetite scores at 6 mo after adjustment for age, sex, ethnicity, baseline body mass index, weight change, and baseline value for respective outcomes (P-interaction = 0.027 and 0.048, respectively). The A allele was associated with a greater decrease in food cravings and appetite scores in participants with high-protein diet intake (P = 0.027 and 0.047, respectively) but not in subjects in the low-protein diet group (P = 0.384 and 0.078, respectively). The weight regain from 6 to 24 mo attenuated gene-protein interactions. Protein intakes did not modify FTO genotype effects on other appetite measures. Conclusion: Our data suggest that individuals with the FTO rs9939609 A allele might obtain more benefits in a reduction of food cravings and appetite by choosing a hypocaloric and higher-protein weight-loss diet. This trial was registered at clinicaltrials.gov as NCT00072995.