Dissertação de Mestrado Nutrição Humana e Metabolismo 2023 Faculdade de Ciências Médicas, Universidade NOVA de Lisboa

Objective: The aims of this study were to evaluate the impact of a 6-month weight loss program (Weight Loss Maintenance 3 Phases Program - WLM3P) on clinically significant weight loss (defined as at least a 5% reduction in weight from the baseline level, and associated with improvements in cardiometabolic risk factors, such as beneficial changes in lipid profile and insulin sensitivity), fat mass and macronutrient distribution, in adults with obesity. Methods: 112 participants with obesity, nondiabetic [BMI (kg/m2 ): 30–39.9] were randomly assigned in equal proportions in a parallel-design weight-loss diet study to 1 of 2 diets: low-carb diet (LCD) or WLM3P. Results: The mean change in body weight from baseline to 6 months was –19% (n=46) in WLM3P compared with −11.9% (n=46) in LCD, for an estimated treatment difference of −7.1% (95% CI, −9.4 to −4.7; P<0.001). 100% of participants in WLM3P and 93.5% in LCD reduced ≥5% of initial weight (P=0.078). The percentage of participants reducing more than 15% of their body weight in 6 months was 73,9% in WLM3P group compared to 32.6% in LCD (p<0.001). At 6 months, WLM3P induced a greater reduction in body fat mass (−9.8 ± 5.3% vs –5.4 ± 4.1%; P<0.001), when compared with a LCD. There was also found a significant correlation between % of lost weight (r=0,44 p<0,003) and protein intake at 6 months, in the control group, in both groups. There was also a significant correlation between variation of body fat percentage and protein intake at 6 months (intervention group: r=0,31; p=0,038; control group: r=0,44; p=0,003). After 6 months of intervention, some macronutrients percentages regarding food intake were significantly different between groups, namely – carbohydrate intake (20.0% (± 8.4) in intervention group vs 26.4% (± 6.7) in control group, p<0.001) and protein intake (31.7% (± 4.4) in intervention group vs 26.6% (± 5.7) in control group, p<0.001). The estimated total energy intake was also significantly different between groups (1292kcal (± 150) in intervention group vs 1488kcal (± 325) in control group, p<0.001). Conclusion: After a 6-month intervention for adults with obesity, WLM3P showed a greater reduction in body weight and fat mass than the LCD, with 100% of participants achieving clinically significant weight loss (> 5% from baseline). More studies are needed to understand the effects of WLM3P on the long term. These results show that WLM3P can be used to improve patient care and enable evidence-based recommendations for sustained weight loss and that protein intake largely influences body weight and fat mass loss.