The β3-Adrenergic receptor gene polymorphism Trp64Arg (ADRB3 Trp64Arg) may be associated with weight gain, especially in the East Asian populations. To date, however, the results of various investigations aimed at determining whether ADRB3 Trp64Arg has any effect on weight reduction after intervention have been inconsistent. The aim of this study was to assess the effect of ADRB3 Trp64Arg on weight reduction in a non-pharmacological intervention program.

Fifty-seven Japanese men (average age 48.1 ± 5.9 years) whose body mass index (BMI) was >23.0 kg/m² participated in an intervention program in which they were encouraged to exercise by walking with a pedometer for 12 weeks. The BMI was measured at the start of the intervention program and on weeks 4, 8, and 12 (end) of the intervention period. The reduction in the BMI (ΔBMI) was calculated as the BMI value obtained at each point in comparison to the baseline (initial) BMI. The participants were classified into two groups: Arg allele non-carriers (Trp/Trp) and Arg allele carriers (Trp/ Arg or Arg / Arg ), respectively.

Among the participants, 61.4% were Trp/Trp homozygous, 38.6% were Trp/ Arg heterozygous, and 0.0% were Arg / Arg homozygous. There was no significant difference in the ΔBMI between Arg allele non-carriers and Arg allele carriers at week 4 [non-carrier mean ± standard deviation (SD) vs. carrier mean ± SD: 0.25 ± 0.43 vs. 0.24 ± 0.35, respectively; p = 0.954], week 8 (0.56 ± 0.68 vs. 0.58 ± 0.61, respectively; p = 0.913), and week 12 (0.70 ± 0.86 vs. 0.84 ± 0.80, respectively; p = 0.545).

Our results suggest that ADRB3 Trp64Arg does not influence BMI reduction after an exercise-based intervention program.