The TaqIA RFLP is associated with attenuated intervention-induced body weight loss and increased carbohydrate intake in post-menopausal obese women

Introduction: Polymorphisms of the dopamine receptor D2 (DRD2) gene have been associated with obesity phenotypes. Our aim was to examine if the genotype of TaqIA Restriction Fragment Length Polymorphism (RFPL) was related to an attenuated weight loss response or to changes in energy expenditure (EE) and food preference before and after weight loss. Methods: Obese post-menopausal women (age = 57.1 ± 4.6 yr, weight = 85.4 ± 15.4 kg and BMI = 32.8 ± 4.5 kg/m2) were genotyped for TaqIA (n = 127) by using PCR–RFLP analysis and categorized as possessing at least one copy of the A1 allele (A1+) or no copy (A1−). Women were randomized into two groups, caloric restriction (CR) and caloric restriction + resistance training (CRRT) and in this study were further classified as follows: A1+CR, A1+CRRT, A1-−CR and −A1−CRRT. Body composition, total daily EE, physical activity EE, Resting EE (REE), and energy intake were obtained at baseline and post-intervention using DXA, doubly-labeled water, indirect calorimetry, and 3-day dietary records, respectively. Results: Overall, all of the anthropometric variables and REE significantly decreased post-intervention (p < 0.001). Women in the CRRT group lost significantly more fat mass (FM) than the CR women (p < 0.05). There were significant time by group by allele interactions for attenuated body weight (BW), BMI, and FM loss for A1+ (vs. A1−) in CRRT (p < 0.05) and for increased % carbohydrate intake (p < 0.01). Conclusion: TaqIA genotype was associated with body weight loss post-intervention; more specifically, carriers of the A1 allele lost significantly less BW and FM than the A1− and had increased carbohydrate intake in the CRRT group.

► We examined the impact of the Taq1A polymorphism on weight loss by two modalities.
► Obese women performed 6 months of energy restriction by diet or by diet + exercise.
► A1+ (vs. A1−) carriers lost less body weight and fat mass in diet + exercise group.
► A1+ (vs. A1−) carriers increased carbohydrate intake in diet + exercise group.
► Novel findings are that Taq1A genotype differently impacts weight loss by modality.