Dairy products boost metabolism and aid weight loss.
Calcium's leading role is legendary. In fact, there seems to be no end to calcium's repertoire: It strengthens bones and teeth and new studies suggest that it may also prevent colon cancer, and even keep Montezuma's revenge at bay.
There's also good evidence that diets high in calcium are associated with reduced rates of being overweight or obese.
"At midlife, women tend to gain one-quarter to one-half a pound per year whether they want it or not, and it all goes to their waist," says Robert Heaney, MD, an internationally recognized expert in bone biology and calcium nutrition with Creighton University in Nebraska.
"We've found that women with the highest dairy intake have an average weight gain of zero, and those with the lowest dairy intake gained a pound per year," Heaney tells WebMD.
There's one catch: You also must cut back on calories for weight loss to happen. "Dairy will only help you lose weight if you have reduced calories. If you add it to what you eat all the time, it won't make a whit of difference," Heaney explains.
Michael Zemel, PhD, director of The Nutrition Institute at the University of Tennessee at Knoxville, is actually the hero of this tale.
In studies of both mice and men, Zemel and colleagues have been the first to show that calcium stored in fat cells plays a crucial role in regulating how fat is processed and stored by the body. The more calcium there is in a fat cell, the more fat the cell will burn -- and the greater the weight loss, Zemel says.
The mouse evidence: In one study, Zemel used mice that were specially bred to be obese. He fed the mice a high-fat, high-sugar diet for six weeks. All had a 27% increase in body fat.
He then put the mice on a restricted-calorie diet, and gave calcium to two groups of them.
The calcium made a big difference. Mice that didn't get any calcium had an 8% loss of body fat. Mice getting calcium supplements had a 42% decrease in body fat.