Weight loss maintenance in primary health care: a randomised controlled trial

This study evaluates the maintenance of a clinically meaningful weight loss (≥ 5 %) after 12 and 36 months of participation in an intervention to promote fruit and vegetable (FV) consumption. A randomised controlled trial was conducted in a primary health care service. For 7 months, participants in the control group (CG) and in the intervention group (IG) performed guided physical exercise three times/week; the IG also participated in collective activities to promote FV consumption. This study selected participants (<i>n</i> 267) who showed clinically meaningful weight loss after nutritional intervention. Sociodemographic, health and body weight data were collected in a face-to-face interview at baseline (T0) and after intervention (T1). Participants were reassessed after 12 (T2) and 36 months (T3) by telephone interview, and the self-reported weight was corrected. The outcome measures weight changes at three time points: M1, comparing T2 with T1; M2, comparing T3 with T2; and M3, comparing T3 with T1. The generalised estimating equation, adjusted for individual characteristics, was used. Participants in the CG showed an increase of 4·2 kg (<i>P</i> < 0·001) at M1 and 4·6 kg (<i>P</i> < 0·001) at M3, while IG individuals showed an increase of 3·6 kg (<i>P</i> < 0·001) at M1 and 3·8 kg (<i>P</i> < 0·001) at M3. The between-group analyses show the effect of nutritional intervention on the maintenance of weight loss at M2 (<i>P</i> = 0·033). Although CG and IG participants increased in weight, the nutritional intervention was associated with maintenance over the long term. This reveals the importance of the promotion of FV consumption for body weight maintenance.