To evaluate the effect of diet versus exercise intervention on weight reduction.

Participants were randomly divided by gender, age, and living area into four groups: group DE (diet and exercise, n = 16), group D (diet only, n = 15), group E (exercise only, n = 15), and group C (control, n = 16). This study ultimately aimed to help participants reduce their body mass index (BMI) by 7% of baseline value. Subjects were 62 residents (men and women ranging in age from 40 to 69 years) of two residential areas in Nara Prefecture, Japan, who participated in annual health checkups in 2006. BMI of the participants was ≥24 and 2 at baseline examination. All participants agreed to undergo a 6-month intervention between January 2007 and September 2007.

In our intention-to-treat analysis, mean change in BMI from baseline to final examination was as follows: group DE mean BMI decreased 6.6%, group D mean BMI decreased 5.3%, group E mean BMI decreased 2.3%, and group C mean BMI decreased 2.2%. The reduction in BMI from baseline to final examination was significant in all groups (DE, p p p = 0.009; C, p = 0.019). Further, mean abdominal circumference was significantly reduced in all groups. Blood glucose levels were significantly reduced only in group DE ( p = 0.047).

Combined intervention with diet and exercise proved to be effective in weight reduction, whereas exercise intervention alone was not found to be effective.