The next step is to figure out a way to study the possible effect of protein in humans. That could be a challenge, however, because researchers would have to tightly control the food that participants eat.
"This would have to be relatively short duration," Newgard said. "You can't put people on diets for long periods of time."
But for now, Newgard said, he "certainly would not recommend increasing protein intake as a mechanism of treating obesity."
"If you have a poor dietary pattern to begin with, when you're eating too much fat and sugar and you're also eating too much protein, that's where the problems unfold," he added.
But Lona Sandon, a spokeswoman for the American Dietetic Association, said the research is too preliminary to produce recommendations for people.
"Most people can get more than adequate protein from eating regular and balanced meals throughout the day that include quality lean protein," added Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern. "Protein shakes are unnecessary for most populations."
Still, she stressed, it's important to understand someone's lifestyle before giving specific recommendations about protein consumption.
The U.S. Department of Agriculture has more on nutrition.
SOURCES: Christopher Newgard, Ph.D., professor, medicine, and director, Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, N.C.; Lona Sandon, R.D., spokeswoman, American Dietetic Association, and assistant professor, clinical nutrition, University of Texas Southwestern Medical Center at Dallas; April 2009 Cell Metabolism
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