Predictors of programme adherence and weight loss in women in an obesity programme using meal replacements

To explore predictors of programme adherence and weight loss in patients participating in a weight management programme using meal replacements (MR).

One hundred and fifty healthy obese women, age 48.5 years (s.d. = 8.3); weight, 97.6 kg (13.4); body mass index (BMI) 36.5 (3.7), participated in a longitudinal study with a 16-week acute weight loss phase (Phase 1) followed by 1 year of a trial of weight-loss maintenance (Phase 2). Energy intake during Phase 1 totaled 900 kcal (3.7 MJ) a day from a diet including two MR. Energy intake during Phase 2 consisted of either MR or a low-fat diet with a calculated energy deficit of 600 kcal/day (2.5 MJ).

Weight, height and waist circumference were measured and body composition assessed by air plethysmography (Bodpod). Glucose and insulin were measured by standard immunoassays and insulin sensitivity assessed by homeostatic model assessment.

At the end of 16 weeks, 114 subjects (76%) completed Phase 1 and achieved a mean weight loss of 8.95 kg (3.38). Adherence to Phase 1 was predicted by weight loss over the first 2 weeks (p < 0.001). Weight loss during Phase 1 was predicted by initial weight and initial systolic blood pressure. Adherence to Phase 2 was not predicted by physiological measures. Weight loss maintenance in Phase 2 (not gaining more than 3% of the weight at start of phase 2) was predicted by cholesterol and triglyceride measured at the start of Phase 2 but otherwise was not predicted by the physiological measures. Initial insulin sensitivity did not predict weight loss in either phase.

Participants whose weight loss over the first 2 weeks falls in the bottom third may need additional intervention if they are to continue in this type of programme. A battery of physiological measures at entry to a MR weight loss and maintenance programme explains only a very small proportion of the variation in weight loss.