Influence of Obesity-Related Genotype on Weight Loss Success, Changes in Body Composition, Biochemical Markers, and Quality of Life While Participating in a 6-Month Weight Loss Program

The purpose of this study was to determine whether genotype of some obesity-related genes (FABP2, PPARG, ADRB2, ADRB3) impacts health outcomes from participation in a 6-month weight loss program. Fifty-one overweight/obese women (41.8 ± 12.1 yrs, 35.3 ± 8.0 kg/m^2 ) were randomly assigned to diet based on genotype, true or false match. Dietary intervention included two hypocaloric (week 1: 1400 kcal/d, weeks 2-24: 1500 kcal/d), moderate protein (45% kcal from protein) diets with variations in carbohydrates and fat (LC- 20:35, MC- 30:25). Participants performed a resistance-exercise program four days/week, and 10,000 steps/day three days/week. Anthropometrics, body composition, REE, dietary data, biochemical markers, and psychosocial evaluation were collected monthly. VO2peak, muscular strength and endurance were assessed at baseline, 3- and 6-months. All measures were analyzed with repeated measures MANOVA. Significant genotype effects and trends favoring false matches were observed for body weight (F-5.6±5.0, T-5.0±5.0 kg, p=0.10), fat free mass (F-0.4±2.3, T-0.8±2.3 kg, p=0.09), android total mass (F-849.1±882.8, T-669.7±855.4 grams, p=0.05), android fat mass (F-627±583, T-459±480 grams, p=0.07), gynoid fat free mass (F+3.0±665, T-199±534 grams, p=0.09), and fasting insulin (T+1.9±5.3, F+0.2±5.1 microIU/mL, p=0.04). Significant time x genotype interactions and trends favoring false were observed for triglycerides (T-9.9±62.3, F-35.5±49.1 mg/dL, p=0.05). Genotype effect favoring true was observed for android fat free mass (T-210.5±451.7, F- 222.0±463.8 grams, p=0.04), gynoid total mass (T-878±978, F-852±1073 grams, p=0.09), and hip circumference (T-5.1±5.5, F-4.9±3.7 cm, p=0.07). Significant genotype x diet interaction and trend was observed in favor of true MC for LDL (TMC-15.8±26.7, FMC-8.6±34.2, FLC+3.7±28.1, TLC+10.1±26.3 mg/dL, p=0.02) and cholesterol (TMC- 26.0±32.1, FMC-23.5±32.0, FLC+7.0±31.8, TLC+8.5±35.8 mg/dL, p=0.06). Overall, false matches experienced greater improvements in body composition, fitness, and biochemical markers