One key to a successful weight loss plan is to lose body fat while sparing lean muscle tissue. While losing weight or body fat is never easy, many consumers who do achieve success often find that keeping the weight off over time is even more challenging.

The ability to lose weight and keep it off is the central focus of a health and wellness-focused collaborative study led by researchers from the University of Colorado Anschutz Medical Campus with support from DuPont Nutrition & Health. The study, published in the June edition of Obesity Science & Practice, evaluates the effectiveness of incorporating soy protein-based foods into higher protein energy-restricted diet for weight loss, compared to other sources of protein, in adults with overweight and obesity. Other studies have demonstrated the success of high protein diets for weight loss. This study examined the effectiveness of a 4-month energy-restricted, higher protein weight loss intervention followed by an additional 8-month weight maintenance phase.

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 6kg 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 20g 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, Ph.D., 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.

You can read the journal article that presents the study’s findings here.