The results showed that both groups who were prescribed a high protein, energy-restricted diet lost similar and significant amounts of body weight. Further, the majority of the weight lost was fat mass. Some participants regained weight during the self-directed, eight-month follow-up period, but there were no significant differences between the dietary treatment groups for any of the outcome measures throughout the 12-month trial.
Both groups lost an average of 3-4% body fat or over 6 kg of total fat loss during higher protein energy-restricted weight loss phase. The participants maintained 4 kg fat loss through the end of the yearlong intervention.
“Protein is an important part of a weight loss diet,” said Ratna Mukherjea, technical fellow with DuPont Nutrition & Health. “Lean sources of high quality protein, such as soy, support improvements in body composition with greater loss of fat tissue versus lean tissue.”
The foods included in the trial, developed by food scientists at DuPont Nutrition & Health, contained 20 g of lean, high quality soy protein per serving, and were delivered in the form of a dry-blended beverage, a lean, meat-free, sausage-like soy patty and a nutrition bar. These options were available to subjects during the weight loss and maintenance phases of the study. Results of this trial provide evidence that the consumption of foods high in soy protein can be an important part of a weight loss diet, supporting lean mass and fat loss, as well as helpful in maintaining those improvements over time.
“A major take home message from this study is that people following a plant-inclusive or plant-based high protein diet can be successful in reducing body weight,” said James O. Hill, PhD, a leader in weight loss research and the study’s senior author. “This study was more about long-term wellness associated with weight reduction. A major struggle for dieters is maintaining their new weight and all the health benefits that accompany weight loss over time.”
Soy protein is a plant-sourced, high-quality protein, comparable in efficacy to other proteins for weight loss among healthy, middle-aged overweight and/or obese adults. In addition, soy protein-containing diets have been shown to support long-term health, mitigating risk factors associated with cardiovascular disease. These findings are especially relevant for dieters who choose to follow dietary advice to increase consumption of plant sources, such as that of the Dietary Guidelines for Americans or those who strive to adhere to a flexitarian or vegetarian eating pattern.