Background/Aim: Body weight loss is essential to lower risk factors for type 2 diabetes and cardiovascular diseases in overweight patients. Therefore, we examined the effectiveness of the Rééducation Nutritionnelle et Psycho-Comportementale (RNPC^®) program, designed to improve metabolic parameters during weight loss, among different patient groups.

Methods: The RNPC^® program, used in 54 French centers, starts with an energy-restricted 800–1000 kcaL/day high-protein, low-carbohydrate, and low-fat diet comprising real foods and meal replacement products. The 89% (n = 10,809) of the patients completing the ∼15-week weight loss phase had a median 11% of initial body weight loss and was included in the study. The weight stabilization phases of the program were not included as metabolic risk markers were only sporadically measured in those phases.

Results: A total of 70.3% were obese and 30.3% classified as having the metabolic syndrome. Without differences in weight loss, improvements in fasting glucose were 0.1 mmoL/L (95% CI -0.2; -0.03, P < 0.05), 0.6 mmoL/L (95% CI -0.7; -0.5, P < 0.001), 3.0 mmoL/L (95% CI -3.6; -2.5, P < 0.001) and 2.0 mmoL/L (95% CI -3.1; -0.8, P < 0.05) for men with pretreatment fasting glucose of <5.6, 5.6–6.9, ≥7.0, or receiving diabetic medication, respectively. Similarly, the largest improvements in triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and alanine transaminase levels were found among male patients with the worst baseline level. Comparable results were obtained for females.

Conclusion: Weight loss during the RNPC^® program is followed by overall metabolic improvement that is mainly driven by substantial improvements in specific metabolic risk markers among those with highest baseline values.