November 24, 2008

High-Protein Meals Rev Up Fat Burning

New Australian research suggests that overweight and obese people can increase the amount of fat they burn by simply consuming higher-protein meals.

While previous studies have shown that thin people are more efficient fat burners than those who are overweight, the current research examined whether the protein composition of meals influenced that weight-related disparity.

The researchers found that overweight men and women burned more fat after consuming high-protein meals than after eating lower-protein meals.  In other words, the additional protein seemed to compensate for the fat-burning deficit observed in overweight people.

"Our research suggests that people with higher body fat burn fat better after a high-protein meal than people with lower levels of body fat," lead researcher Dr. Marijka Batterham of Australia's University of Wollongong told Reuters.

Multiple studies have also suggested that high-protein diets may help people lose weight, in part because protein may suppress appetite more than fat or carbohydrates.

However, since the Australian study did not measure weight loss, researchers cannot yet say whether the increased fat-burning observed in the participants would result in additional weight loss, Batterham said.  Addressing that question is the next step, she said.

The study involved 18 adults, with an average age of 40 years, whose post-meal metabolism was tested on 3 separate days.  Eight subjects were classified as overweight, while six had a normal weight and four were obese.

On the study's first day, participants were given a "control" breakfast and lunch composed of 58 percent carbohydrates and 14 percent protein. On the remaining 2 days, they consumed more balanced meals, with roughly one third of the calories consisting of protein and another third from carbohydrates.  The protein-rich meals contained low-fat dairy, eggs and lean meat, along with vegetables and bread as carbohydrate sources.

The researchers found that overweight and obese participants burned less fat than their thinner counterparts did during the 8 hours following the control meal. However, that disparity disappeared when participants consumed the higher-protein meals.

Batterham said she and her team are now studying whether vegetarian sources of protein have similar effects on fat metabolism in overweight adults.

Experts generally recommend that those looking to increase the amount of protein in their diets choose foods such as fish, poultry, low-fat dairy, beans and nuts.

The study was published in the journal Nutrition & Dietetics.


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