This well-controlled study found that when exercising adults on a slightly reduced-calorie diet consumed 3 to 4 servings of dairy foods daily, their metabolism changed so that their bodies burned more fat than they did when they had one serving of dairy under the same conditions.

"The design of this study is very strong as all of the subjects consumed both diets at different times and served as their own controls," noted Edward Melanson, Ph.D., lead investigator and assistant professor of medicine at the University of Colorado. "Our data suggest that when you restrict calories slightly and increase calcium intake by increasing the number of low-fat dairy servings, the amount of fat you burn over 24 hours is increased. However, the precise explanation of how increasing dairy servings impacts fat metabolism and body weight is still unclear."

The study included overweight men and women, ages 20 to 50, who usually exercised less than three hours a week. Over the course of seven weeks, the subjects participated in four one-week periods in which they consumed either a low-dairy diet or a diet including 3-4 servings of dairy foods each day. Several times during the study, participants' rate of fat oxidation (burning) was measured over a 24-hour period in a room calorimeter, an enclosed area in which very specific measurements can be taken. Room calorimeter studies are usually done with only a few subjects, but this current study included 19 men and women, a particularly large group for this kind of study.

This research shows how reducing calories and exercising while consuming adequate dairy foods can help improve the body's ability to burn fat which may lead to the loss of body fat as seen in weight loss studies.(2,3,4) In fact, this is the third study in the last six months to add support to the body of research showing a connection between dairy and weight-management.(1,4,5)

"If weight loss is the goal, then striving to consume enough dairy products to meet the recommendations for calcium may be beneficial in terms of weight loss. A few other studies have shown that there may also be beneficial effects on cholesterol," noted Dr. Melanson. "For most people, this would be about 2-4 servings of low-fat dairy foods each day."

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