Which Is More Important Diet or Exercise for Obese Patients?

Abstract

Abstract Objectives The obese population is increasing worldwide and Japanese are no exception. It is a natural hope that obese patients want to lose weight effectively and not lose as much muscle mass as possible. In our study, we examined which diet or exercise regimen could most effectively reduce body weight and reduce muscle loss in severe obese patients. Methods This study was an open-label randomized controlled trial carried out in Shinkomonji Hospital, Kitakyushu, JAPAN. Total 16 patients with severe obesity (body mass index ≥35 kg/m2) were randomly divided into the Normal Formula Diet (NFD) and Protein Rich Formula Diet (PRFD) groups. The participants of each group were randomly assigned to the aerobic and resistance exercise groups. All participants were hospitalized for one month. During hospitalization, the nutritional composition was predetermined as 50% carbohydrate, 20% protein, and 30% lipid of total 800 kcal in the NFD group, and 30% carbohydrate, 40% protein, and 30% lipid of total 800 kcal in the PRFD group. In the aerobic exercise group, an exercise intensity of 4 to 6 METs was performed at 2100 METs × min/week. In the resistance exercise group, an exercise intensity of 6 to 8 METs was performed at 2100 METs × min/week. Muscle mass was measured every week by bioelectrical impedance assay using the InBody S10 body composition analyzer (InBody Japan Inc., Tokyo, Japan). Results The mean body weight was 124.3 kg and the mean age was 38 years with a gender distribution of 50% male. One month later, the rate of body weight loss was PRFD-aerobic (–25 kg, −20.2%), PRFD-resistance (–21 kg, −16.9%), NFD-aerobic (–18 kg, −14.5%), and NFD-resistance (–16 kg, −12.9%) groups. These were significantly larger in order (P = 0.041). The rate of muscle loss was PRFD-resistance (–8 kg, −6.5%), NFD-resistance (–11 kg, −8.9%), PRFD-aerobic (–12 kg, −9.6%), and NFD-aerobic (–14 kg, −11.3%) groups. These were significantly smaller in order (P = 0.048). In all groups, participants’ renal function did not worsen one month after admission. Conclusions Our study showed the most effective way to lose weight was diet therapy, especially to reduce carbohydrates and increase protein. Exercise therapy was the most effective way for muscle retention, especially resistance exercise was considered to be more effective than aerobic one. Funding Sources None.