Effects of lupin-enriched foods on body composition and cardiovascular disease risk factors : a 12-month randomized controlled weight loss trial

Background: Regular consumption of diets with increased protein or fibre intakes may benefit body weight and composition and cardiovascular disease risk factors. Lupin flour is a novel food ingredient high in protein and fibre. Objective: To investigate the effects of a lupin-enriched diet, during and following energy restriction, on body weight and composition and cardiovascular disease risk factors in overweight individuals.Design:Participants (n131) were recruited to a 12-month parallel-design trial. They were randomly assigned to consume lupin-enriched foods or matching high-carbohydrate control foods. All participants underwent 3 months of weight loss, 1 month of weight stabilization and 8 months of weight maintenance. Body weight and composition and cardiovascular disease risk factors were assessed at baseline, 4 and 12 months. Results: Lupin, relative to control, did not significantly influence (mean difference (95% CI)) weight loss at 4 months (0.1 kg (1.2, 1.4)) and 12 months (0.6 kg (2.0, 0.8)), maintenance of weight loss from 4 to 12 months (0.7 kg (1.83, 0.48)) or measures of body fat and fat-free mass. Relative to control, 24-h ambulatory systolic (1.3 mm Hg (2.4, 0.3), P0.016) and diastolic (1.0 mm Hg (1.9, 0.2), P0.021) blood pressures were lower at 12 months but not at 4 months; fasting insulin concentrations and homeostasis model assessment (HOMA) scores were significantly lower at 4 months (1.2 mU l-1 (1.3, 1.1), P0.004 and 0.6 units (1.0, 0.19), P0.004) and 12 months (1.3 mU l-1 (1.4, 1.1), P0.001 and 0.7 units (1.1, 0.24), P0.002). Conclusions: A diet higher in protein and fibre derived from lupin-enriched foods does not enhance weight loss or improve the maintenance of weight loss. However, such a diet may provide cardiovascular health benefits in terms of insulin sensitivity and blood pressure.