Increased Protein Density During Weight Loss Is Correlated with Reduced Abdominal Obesity and Body Mass Index and Improved Body Composition

Abstract

Abstract Objectives There is a clear link between abdominal obesity and chronic diseases. Dietary changes leading to substantial weight loss reduce obesity and improve health; however, no viable dietary treatment program exists that produces clinically significant, cost-effective, and sustainable weight loss. To test the hypothesis that a diet dense in lean proteins and fiber is inversely associated with abdominal obesity while maintaining skeletal muscle mass (SMM), we evaluated the correlation between mean protein and fiber density and changes in BMI, waist circumference and SMM during weight loss. Methods Thirty adult males and females participated in this ongoing, 2-year dietary weight loss program. The Individualized Dietary Improvement Program focused on reducing caloric intake and increasing protein (7–11 g/100 kcal) and fiber (1.8–3.2 g/100 kcal) density to desired ranges. Participants attended 19 group educational sessions, 3 individual counseling appointments, self-weighed daily, and submitted monthly 24-hour dietary recalls. BMI, waist circumference and body composition (InBody) measurements were collected at baseline and after 6 months. Results At 6 months, 25 participants (24–70y) remained in the study with 18 completing all body measurements. Mean weight loss (n = 25) was −2.2 ± 0.5 BMI points (–5.2 ± 1.3% of initial body weight) and mean waist circumference reduction (n = 18) was −6.5 ± 1.3 cm from baseline. Significant increases in protein and fiber density were seen from baseline to month 2 (P < 0.05). There were direct inverse associations between mean protein density and both reduced waist circumference (P < 0.01) and reduced BMI (P < 0.01). Fiber intake had no significant impact on weight loss, and maintenance of SMM did not significantly correlate with mean protein density. However, only 11.0 ± 3.2% of weight lost was due to the loss of SMM, supporting the efficacy of the program. A significant positive correlation (P < 0.01) existed between fat mass loss and protein density, with 74.3 ± 4.7% of excess body fat accounting for total weight lost. Conclusions Increased protein density correlates with accelerated loss of fat mass, greater reductions in abdominal adiposity, and may protect SMM from degradation during weight loss. Funding Sources This research is supported by the NIBIB of the NIH and the USDA NIFA.