Assessing the dairy industry's weight-loss claims

New ads for dairy products go far beyond the milk mustache, now promising viewers that eating more dairy foods can help shrink your waistline.

One ad shows a woman eating yogurt to fit into a bikini. Another shows a glass of milk shrinking to an hourglass shape, ending with the tagline "Milk your diet."

But while consuming more milk and yogurt may sound appealing to dieters, losing weight by eating more dairy isn't as simple or clear cut as the ads suggest.

Numerous scientific studies — in both rats and people — do show a link between dairy consumption and weight loss. But to lose weight, dairy dieters still have to dramatically scale back calories. In addition, little independent research has been done on the topic — most of the dairy diet studies have been funded by the dairy industry. And researchers disagree on just how big of an effect dairy foods really can have on weight management.

The dairy diet got a boost in April, when the medical journal Obesity Research published a University of Tennessee study of 32 obese adults, all of whom cut 500 calories from their daily diet for six months. But while the dieters all counted calories, one group consumed three daily servings of dairy foods. Another group consumed one or fewer servings, and a third added extra calcium via supplements. The study, funded by the National Dairy Council, showed the dieters who ate more dairy lost an average of 11 percent of their body weight, compared with 8.6 percent in the supplement group and 2.5 percent in the low-dairy group.

Unexpectedly, the high-dairy dieters lost far more of their weight around their abdomen — losing about an inch more around their waists than the low-dairy dieters. But while the study is provocative, it was small, and by no means conclusive. The dairy dieters lost about a pound a week — the amount that would be expected on a 500-calorie-a-day deficit.

Exactly how calcium and dairy might help with weight management isn't clear. Dairy products, in general, may simply be more satisfying than other foods, making high-dairy dieters less hungry and more likely to stick to their diet. But the claims of the dairy industry go far beyond diets like Atkins, which advocate dairy foods because of their low-carb count.

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