A review of the literature found that, while there is evidence to support a role for high protein diets for enhancing satiety, energy burning, and fat loss, there is no clear evidence to indicate that there is a difference between plant and animal sources of protein.
Scientists from Laval University in Canada and the University of Copenhagen in Denmark present their findings in the journal Nutrition, Metabolism & Cardiovascular Diseases.
Growing waistline, growing market
With the World Health Organization estimating that by 2015, there will be more than 1.5 billion overweight consumers, incurring health costs beyond $117 billion per year in the US alone, the opportunities for a scientifically-substantiated weight management food product are impressive.
The market for food, beverage and supplement weight management products is already valued at $3.64bn (2009 figures) in the US, according to Euromonitor. In Western Europe, the market was worth $1.3bn in 2009.
“Multiple dietary strategies aiming at reducing body weight and preventing weight gain have been proposed and, in recent years, high-protein diets have attracted considerable attention as possible weight management aids. Intake of protein has been shown to favourably influence satiety, thermogenesis, energy efficiency and body composition, particularly during weight- reducing programs,” explained the scientists.
“Furthermore, a modest increase in dietary protein content has proven effective in preventing weight regain after a major weight loss in obese subjects, as demonstrated in the recent European multicenter trial Diogenes.
“However, little is known about the effect of protein quality on the regulation of energy balance,” they said.
Filling the gaps
In addressing this question scientists led by Copenhagen’s Arne Astrup set out to test their hypothesis that plant and animal proteins provide similar effect on body weight regulation.
Reviewing the literature they found that animal proteins, and in particular dairy proteins, are superior to plant proteins for building muscle, but the was “ no clear evidence to indicate whether there is a difference in the effect dependent on the source of the protein”, they said.
The scientists do note, however, that the evidence to date from intervention studies is “inconclusive […] and the literature is still incomplete”.
Recommendations
According to the American Food and Nutrition Board, the recommended dietary allowances (RDA) for protein and AA for adults are 0.8 g of protein per kg of body weight. This is equivalent to about 56 grams for a 70 kg person.
There is no established upper limit.
Source: Nutrition, Metabolism & Cardiovascular Diseases
Published online ahead of print, doi:10.1016/j.numecd.2010.12.008
“Effect of proteins from different sources on body composition”
Authors: J-A. Gilbert, N.T. Bendsen, A. Tremblay, A. Astrup