Abstract
(1) Multimodal treatment is a standard treatment for patients with obesity. However, weight loss also leads to reductions in fat-free mass. The aim was to investigate whether additional protein intake contributes to better preservation of lean body mass (LBM). (2) A total of 267 obesity patients (age 45.8 years; BMI 47.3 kg/m(2)) were included in this analysis. For the first 12 weeks of the program, patients were given a formula-based diet of 800-1000 kcal per day. Patients were divided into a control group (CG) (n = 148) and a protein group (PG) (n = 119). The PG was characterized by an additional protein intake with the aim of consuming 1.5 g of protein per kilogram of normalized body weight, whereas the CG had a protein intake of 1 g/kg/d. Bioelectrical impedance analysis was performed at the beginning (t0) and after 12 weeks (t1) of the program. (3) There were no significant differences between the groups with respect to weight loss (p = 0.571). LBM was also significantly reduced in both groups, without significant differences between CG and PG. (4) Increased protein intake had no significant effect on body composition of morbidly obese patients during a 12-week formula-based diet and multimodal treatment.