Weight loss maintenance for 1 year after a 6-month diet and physical activity program in obese Japanese men

Abstract

This study described 1-year changes in body weight and metabolic syndrome components in middle-aged obese Japanese men participating in a 6-month weight loss program. This study comprised two phases: 6-month weight loss program and 12-month weight maintenance. Data were collected at Tsukuba, between July 2009 and February 2011. Overweight or obese Japanese men aged 40-64 years without any cardiovascular disease history participated. The primary outcome was the 18-month weight change. Secondary outcomes were 18-month changes in metabolic syndrome components. Primary analyses included all participants who had provided baseline data, and all missing follow-up values were replaced with their baseline data. Of the 58 participants, 39 (67.2%) completed all measurement visits. Their body weight decreased significantly immediately after the 6-month weight loss program (-8.0 kg; 95% confidence interval [CI]: -10.2 kg, -5.8 kg). However, it increased significantly, by 3.7 kg (95% CI: 1.4 kg, 6.0 kg), at Month 18 (a year after the program ended). The 18-month weight loss was 4.3 kg (95% CI: 2.1 kg, 6.5 kg). Among the metabolic syndrome components, visceral fat area, systolic blood pressure, and high-density lipoprotein cholesterol levels improved significantly at Month 18. The other components did not improve over the 18 months. In this study, the obese, middle-aged Japanese men experienced modest weight regains after its substantial reduction. Unlike other ethnicities, factors associated with long-term weight loss maintenance remain understudied among Japanese adults. Therefore, accumulating evidence from Japanese studies with longer follow-up is necessary in the future.