(Food-Beverage-News.Com, November 26, 2012 ) San Francisco, CA -- Research findings show that over an average of 12 weeks, people assigned at random to a high-protein diet lost approximately 0.8kg and more body fat compared to those with a standard-protein diet.
However, based on the protein content of diets, there was no difference in how much participants' blood pressure, cholesterol levels, or markers for diabetes risk fluctuated.
Leading the study, Dr. Thomas Wycherley from the University of South Australia in Adelaide said only a modest weight loss occurred in the high-protein group, but "it may still represent clinical relevance on a population level".
Twenty-four past trials were analysed that included a total of 1,063 participants. They were all put on a reduced-calorie, low-fat diet designed to help them lose weight. Almost half were prescribed a high-protein diet version, containing about 85g of protein a day for a 68kg person. The other half was prescribed a standard-protein diet, with 49g a day, on average, for a 68kg person.
Across all trials, standard- and high-protein diets were designed to provide the same calorie reduction.
Findings published last week in The American Journal of Clinical Nutrition noted that participants lost an average of anywhere from 1.1kg to 11kg, depending on the study.
It is not evident why a higher protein-to-carbohydrate ratio might help people lose more weight. One obesity researcher, not involved in the new analysis, questioned whether the trials could be conclusive on that point.
Dr. James Levine from the Mayo Clinic in Scottsdale, Arizona say, "The studies are generally far too short to tell impact." In addition, "many are inadequately conducted to be relevant".
The body may use more energy and burn more calories processing protein compared with carbohydrates said Dr. Wycherley.
Another possible explanation for the link is that consuming protein assists in the preservation of muscle mass. Even when the body is resting, muscle mass burns more calories than other types of mass.
Dr. Wycherley also stated that people in the studies tended to get protein from a variety of animal and vegetable sources.
