Objective: We conducted a randomized controlled crossover trial to evaluate the effects of a new worksite weight-control programme designed for men with or at risk of obesity using a combination of nutrition education and nutrition environmental interventions.

Subjects and methods: Male workers with or at risk of obesity were recruited for this study at five worksites in Niigata City, Japan, of whom 57 were analysed (intervention group, n = 28, mean age 45.5 years; control group, n = 29, 46.0 years). The intervention group received a six-month programme consisting of nutrition education and the provision of healthy cafeteria meals along with nutritional information, which was thereafter repeated in the control group in a crossover design. At six months and one year after programme entry, primary outcome measures including body weight (BW), body mass index (BMI), waist circumference, blood pressure, and blood biochemistry were evaluated.

Results: At the one-year follow-up, the intervention group had significantly greater reductions in BW, BMI, and alanine aminotransferase than the control group (p = 0.017, p = 0.017, and p = 0.860, respectively).

Conclusion: The effects of the six-month weight-control programme incorporating nutrition education and nutrition environmental interventions were maintained to the one-year follow-up, resulting in significant differences in relevant parameters between intervention and control groups.