Comparison of a dietary intervention promoting high intakes of fruits and vegetables with a low-fat approach: long-term effects on dietary intakes, eating behaviours and body weight in postmenopausal women

The aim of the present study was to compare the long-term effects of two dietary approaches on changes in dietary intakes, eating behaviours and body weight: (1) approach using restrictive messages to limit high-fat foods (low-fat intake; LOFAT); (2) approach emphasising non-restrictive messages directed towards the inclusion of fruits and vegetables (high intake of fruits and vegetables; HIFV). A total of sixty-eight overweight or obese postmenopausal women were randomly assigned to one of the two dietary approaches. The 6-month dietary intervention included three group sessions and ten individual sessions with a dietitian. Dietary intakes, eating behaviours and anthropometrics were measured at baseline, at the end of the dietary intervention (T = 6) and 6 months and 12 months after the end of the intervention (T = 12 and T = 18). In the LOFAT group, energy and fat intakes were lower at T = 6 when compared with baseline and remained lower at T = 12 and T = 18. In the HIFV group, fruit and vegetable intakes increased significantly at T = 6 but were no longer significantly different from baseline at T = 12 and T = 18. Dietary restraint increased at T = 6 and remained higher than baseline at T = 18 in the LOFAT group while no significant change was observed in the HIFV group. At T = 6, body weight was significantly lower than baseline in both groups (LOFAT: - 3.7 (SD 2.8) kg; HIFV: - 1.8 (SD 3.0) kg) and no significant difference in body-weight change from baseline was found between groups at T = 18. We concluded that weight loss was similar at 1-year follow-up in both dietary approaches. Despite relatively good improvements in the short term, the adherence to a 6-month dietary intervention promoting high intakes of fruits and vegetables was difficult to maintain.