It’s seriously time to stop choking down skim milk. If you were raised on the watery stuff and truly prefer it to creamier whole milk, that’s one thing. But if you shun full-fat dairy in favor of lower-calorie, low-, or no-fat versions because you think you’re doing your body good, mounting evidence shows you are wrong. In fact, you may be missing out on some very real health benefits, such as protection against obesity and heart disease.
Now the case for whole milk, full-fat yogurt, and real cheese just got even stronger. According to a new study published in Circulation, adults who consumed the most full-fat dairy — roughly 1.2 servings per day — were 46 percent less likely to develop diabetes than those who consumed the least. One serving of dairy comes out to the amount in one cup of milk, one cup of yogurt, or 1.5 ounces of natural cheese.
Starting back in 1989, researchers from Tufts University and Harvard School of Public Health took regular blood samples from 3,333 adults, all of whom were diabetes-free at the outset, in order to measure circulating biomarkers of dairy fat in their bodies. This method supplied a more objective picture of their actual dairy intakes than the famously unreliable food frequency questionnaires most dietary studies employ. The researchers continued tracking these volunteers until 2010 to see who would eventually develop Type 2 diabetes. Although this study didn’t establish cause and effect, the fact that so many fewer diabetes cases emerged from the high-dairy-fat group certainly speaks to the benefits of the real deal.
One possible explanation is that since dairy fat is filling, it kept these folks from consuming lots of refined carbohydrates and sugar-sweetened beverages, which are known to increase diabetes risk. Full-fat dairy also may have led them to take in fewer calories overall. However, the researchers controlled for these factors in their analysis. In other words, regardless of how many sodas participants swilled or total calories they took down, the link between full-fat dairy and decreased diabetes risk remained.
“Our research shows that dairy fat itself provides protection against diabetes,” says study author Mohammad Yakoob. “But it’s still unclear whether these benefits stem from the particular dairy fatty acids we studied or from others, such as medium-chain saturated fats.” He says other fat-soluble elements of dairy fat, namely vitamin D, may also help stave off diabetes. And in yogurt specifically, the probiotics may be protective, as might the fermentation processes involved in making yogurt. “We know that bacterial cultures used for fermentation can synthesize vitamin K2, which may improve insulin sensitivity,” Yakoob says. Quite possibly, it’s a combination of all of these factors.
Based on this and several other recent studies, Yakoob believes it’s high time we stopped scapegoating fat. “There is too much fear that fat will lead to obesity and adverse cholesterol effects,” he says. “We now know that saturated fats, which include most dairy fats, raise good cholesterol (HDL) along with bad cholesterol (LDL). Thus, they have an overall neutral effect on cholesterol levels and cardiovascular disease risk.”
Accordingly, Yakoob objects to federal nutrition guidelines recommending only low-fat dairy; he’d prefer they promote whole-fat dairy options as well. Beyond dairy, he’s not a fan of reduced-fat versions of other traditionally high-fat foods, either. “Emerging evidence on fat and cardiometabolic health provides reasons to be wary of low-fat foods in general,” Yakoob says. In general, you want to eat food in its closest form to how it's found in nature — mechanically creating a low-fat or no-fat food inevitably changes the structure of a food from how it naturally exists (and oftentimes adds salt or sugar to make up for what is lost in its transformation and keep it palatable).