Can Whole Milk Keep You Thin?
A slew of recent research suggests that the old advice to choose low-fat dairy may be wrong. High-fat dairy products appear to help keep you leaner. Nutrition Diva takes a closer look at this apparent paradox.
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Nutrition Diva listener JoAnn writes: "What is your take on the full-fat paradox--that whole milk may keep us lean?"
JoAnn is referring to a couple of new studies that made headlines recently, suggesting that people who eat more full-fat dairy products actually have a lower risk of obesity--and all the things that go with obesity, such as increased risk of heart disease and diabetes. This, of course, is completely contrary to the conventional wisdom. .
For decades now, we've been advised to choose low-fat dairy products over full-fat, for a couple of reasons. First, low-fat dairy products are lower in calories and, therefore, should help us avoid weight gain. Secondly, the fat in dairy products is largely saturated fat and limiting saturated fat is thought to reduce the risk of heart disease.
I've talked quite a bit in recent months about the increasingly questionable link between saturated fat intake and heart disease risk. People who eat more saturated fat do not appear to have any higher risk of heart disease than those who avoid it.
Surprisingly, the more dairy fat you eat, the lower your risk of developing obesity.
And now this: Eating full-fat dairy products doesn't seem to pack on the pounds. In fact, it seems to ward off excess weight gain over time. In one analysis of 1500 Scandinavian men who were studied over the course of 12 years, those who ate only low-fat dairy products were twice as likely to become obese as those who reported eating butter, cream, and full-fat milk on a daily or near daily basis--even after adjusting for other variables such as vegetable intake, physical activity, alcohol consumption, and age. (And, just in case you're wondering, this research was not funded by the dairy industry!)
Stepping back even further, a recent review looked at 16 different studies that assessed both dairy fat intake and weight gain and/or heart disease risk. In 11 out of the 16, dairy fat intake was inversely associated with obesity and heart disease risk. "Inversely associated" means that the more dairy fat you eat, the lower your risk. And the same appears to be true of kids: children who are given skim and low-fat milk to drink are actually more likely to develop childhood obesity.
See also: Is Milk Bad for You?
All of these are correlations, of course, and not controlled studies. But as these correlations pile up, it may be time to reconsider the conventional wisdom that low-fat dairy products are always preferable.
How Could Butterfat Keep You Lean?
For scientists, the real fun of these sorts of observations is coming up with hypotheses to explain them, and then figuring out how to design a study to test those hypotheses. And there are several things that could explain how eating more butterfat could help keep you leaner.