Effects of a High Carbohydrate and High Protein Formula Diet On Body Composition and Metabolic Risk Parameters in Obese Subjects

Background: In obese subject’s weight loss is known to improve blood lipid profiles, glycemic control and other conditions that may contribute to the development of metabolic syndrome or cardiovascular diseases. However, the optimal dietary carbohydrate and protein composition to facilitate weight loss and improving potential adverse effects is still in debate. Therefore, the aim of this study was to compare the effect of two low-fat formula diets either high in carbohydrate or high in protein, on body composition and metabolic risk factors. Methods: 154 obese (BMI 32.5 ± 0.14 kg/m2) men and women were included in this randomized clinical trial and classified in two groups (highcarbohydrateformula diet (HC) and high protein formula diet (HP)) of 80 matched subjects. They underwent an intervention for eight weeks, which consisted of two phases: (1) week 1 and 2: total replacement of three meals by a formula diet and (2) six week partial formula diet (replacement of 1-2 meals). Measurements were taken prior and post intervention for analysis of body composition and parameters of lipid and glucose metabolism. Results: After eight weeks both groups lost significantly body fat mass (HC: -5.11 ± 0.51 kg, p<0.001; HP: -5.81 ± 0.54 kg, p<0.001), while only for subjects of HP group no change of lean body mass and body cell mass was observed. Metabolic risk parameters were reduced in both the HC and HP group; however, subjects in the HC group showed a higher reduction in triacylglycerol concentration (-29.1 mg/dl vs. -14.0 mg/dl, p<0.04). Further, the prevalence of the metabolic syndrome was reduced in both groups without difference (HC: -17.9%, p=0.004; HP: -18.4%, p=0.003). Conclusion: Our data demonstrate, that even in a short period of time, a low-fat meal replacement diet high in carbohydrate or high in protein is effective in improving body composition and reducing metabolic risk parameters.