Friday, September 12, 2014

Does Protein Really Help You Eat Less?

The Study
In a randomized trial with a crossover design, 30 men and 28 women consumed three different diets for 12 days on separate occasions: 5% of energy from protein, 15% of energy from protein, and 30% of energy from protein. The diets and exercise habits were identical in all three conditions with the exception of the amount of protein consumed.  All meals were consumed at the University that was conducting the study and food consumption was ad lib, subjects could eat as much as they wanted at a meal. When consuming the 5% energy diet, subjects averaged 2,264 calories per day.  When consuming the 15% protein diet, subjects consumed 2,221 calories per day.  When consuming the 30% protein diet, subjects consumed 2,085 calories per day. American Journal of Clinical Nutrition 2014; 99:1397-406.

Take Home Message
This study provides further evidence that higher protein consumption reduces energy intake.  Researchers are not quite sure why protein increases satiety, but it sure seems to in trials.  The difference in calories consumed between the high and low protein diets was 180 calories per day.  This has the potential to have a profound impact on body weight over time.  I have my clients shoot for about 20% of calories as protein, which is a safe level and can really have a positive impact on hunger and subsequent energy intake.

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