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.