= Full article availableThe yogurt ads promise that three servings a day will help you squeeze into an “itsy bitsy, teeny weeny, yellow polka-dot bikini.” A prominent researcher has patented the idea that dairy products promote weight loss. The dairy industry touts the claim in a $200 million ad campaign. But the Physicians Committee for Responsible Medicine, a pro-vegetarian group that believes milk isn’t healthy, is petitioning the federal government, saying claims that dairy consumption promotes weight loss are false and misleading.
What’s a confused consumer to believe?
Despite the recent petition to the contrary filed with the Federal Trade Commission and US Food and Drug Administration, evidence is emerging for a link between dairy consumption and weight loss–if you’re also cutting overall calorie intake. The National Dairy Council’s Web site lists eight pages of research along those lines. Most of the studies, however, were either done on animals or were observational studies of uncontrolled groups of people, not controlled clinical trials.
The two published clinical trials most often cited by the dairy industry involved small sample sizes and, critics note, were funded by the dairy council or General Mills, which makes Yoplait yogurt. Michael B. Zemel, MD, director of the University of Tennessee’s Nutrition Institute, led both studies and has since taken the unusual step of patenting his findings, so dairy companies must pay him to cite his studies in their ads.
Reading the fine print in those ads makes clearer what Dr. Zemel actually concluded, which is not simply that upping your dairy consumption will peel off the pounds. In the first study, published last year in Obesity Research, he spent 24 weeks studying 32 obese adults. All consumed 500 calories a day less than the level needed to maintain their current weight, but their diets varied in the amount of calcium and how it was obtained. Those taking an 800-milligram calcium supplement lost more weight and more abdominal fat than the control group. But the subjects getting 1,200-1,300 milligrams of calcium daily in their diets rather than by popping a pill lost the most weight and fat.
In a second study, published this year in The International Journal of Obesity, Dr. Zemel followed 34 healthy obese adults over 12 weeks. Those who ate three servings of yogurt daily lost more weight and body fat than the group consuming only one serving of dairy a day.
Other studies have suggested that calcium may play a role in the regulation of body weight. The Heritage Family Study, published last year in the Journal of Nutrition, found an association between calcium intake and body fat, especially abdominal fat, in men and white women.
Dairy foods may also protect against insulin resistance syndrome (IRS), also known as metabolic syndrome, which increases the risk of cardiovascular disease and Type 2 diabetes. The Cardia study, published in 2002 in the Journal of the American Medical Association, followed 3,157 adults ages 30 and under for 10 years; it found that each additional daily serving of dairy was associated with a 21 percent lower risk of IRS.
The jury’s still out, however, on whether dairy consumption actually helps control weight in the absence of a significant reduction in calorie intake. A Purdue University study, published recently in the American Journal of Clinical Nutrition, compared the dairy consumption and body weight and fat of 155 healthy, normal-weight women ages 18 to 30 over a year’s time. The researchers found no significant association between dairy consumption and weight or body fat changes.
That doesn’t mean there aren’t other good reasons to get plenty of low- or non-fat dairy products, however. The new federal dietary guidelines recommend three servings of dairy daily; one serving is eight ounces of milk or a cup of yogurt. (Note that yogurt, while a good source of calcium, doesn’t deliver the vitamin D that milk does.) Getting calcium through your diet is better than taking supplements, as Dr. Zemel’s research, among others, has shown.
And remember that consuming whole dairy products will more than undo any possible weight-loss benefits. Drinking three glasses of whole milk daily instead of skim adds more than 200 calories–which could put on more than 20 pounds over a year.
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