I think dairy is one of the few foods that people find to be pretty much universally delicious. Milk, cheese, and other dairy products are not only tasty additions to any meal, they are also high in protein, calcium, and other nutrients important for athletes. For some people, raw milk has been a staple for so long that it is very nearly a paleo food. However, the healthiness of dairy is often brought into question.


dairy and insulin, insulin impact of dairy, insulin levels and milk, milkAs a source of nutrition, dairy is a food with the capacity to help small animals become large animals. In the case of cow’s milk, it will make them very large indeed. So not only do dairy foods have a lot of protein, but they generally have a lot of carbs and fat as well. Now of course we can choose low fat versions of dairy these days, but dairy also has lactose, an interesting sugar that is low in glycemic value, but seems to have a potent effect on insulin. It’s the primary reason it is extremely difficult to drink a gallon of milk in an hour. One would think it can’t be good for your insulin system. As luck would have it, in a recent study published in the Nutrition Journal researchers looked at the effect of dairy on insulin and other factors in depth.


This was a “free living” study. Meaning that it’s 23 participants didn’t have strict laboratory conditions. Each lived a normal life and ate a normal diet with one exception. Some of the participants were told to eat no more than the provided two servings of low fat dairy per day and the rest were told to eat four servings.


Breaking Muscle Shop

The provided dairy products were low fat milk and low fat yogurt, if you’re curious. The participants followed their plan for six months, the researchers prodded and probed them, and then they switched to the diet they were not on and followed that one for another six months.


Ultimately pretty much nothing was different between the groups, with one important exception - insulin. Plasma insulin was 9% lower in the high dairy group and insulin resistance was reduced by 11%. It was theorized that several nutritive compounds in dairy act to improve your insulin system. So without any apparent detriment, the participants experienced a pretty substantial benefit when consuming dairy.


Improving insulin response and lowering resting insulin levels are key for athletes. A better running insulin system means more energy, less body fat, and more muscle. It’s pretty clear this is something to shoot for.


These results are a little surprising to me. I assumed that given the strange effects lactose has on insulin, that a high dairy consumption would abuse the insulin system and perhaps even contribute to diabetes. On the contrary, the researchers noted a trend of reduced incidence of diabetes, particularly when consuming low fat and perhaps hormone free dairy.


Apparently dairy is good for insulin, despite the high sugar content of the low fat dairy foods in this study. As such, it would seem to be a good addition to any athlete’s diet - just don’t go overboard. Even the low fat varieties are still very nutrient dense. I’d recommend dairy consumption be saved for your post-exercise meal. 



1. Todd C Rideout, et. al., “Consumption of low-fat dairy foods for 6 months improves insulin resistance without adversely affecting lipids or bodyweight in healthy adults: a randomized free-living cross-over study,” Nutrition Journal 2013, 12:56


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