Dairy and Weight

Although the dairy council no longer advertises that drinking milk or eating yogurt will help you lose weight, there's the occasional patient who will ask about it. Usually we tell them about the two studies we've reported on, first way back in 2006 and then another in 2009, that essentially concluded that dairy products by themselves would have no impact on weight: the gold standard for weight loss is still calories in versus calories out.

A meta-analysis (a study incorporating the data from multiple, smaller studies) published recently in the American Journal of Clinical Nutrition revisits the question of weight and dairy products (2012;96(4):735-47). Nearly 30 different randomized controlled trials, including over 2,000 participants, were included in their study. The participants had to be over the age of 18 and the studies had to last for at least 4 weeks in order to be included in the meta-analysis. The different types of dairy used in the studies varied from low-fat milk to powdered milk to cheese and yogurt.

After standardizing the portions of dairy products across the multiple studies, the researchers were able to compare the outcomes of the studies with respect to weight loss and body fat in the case of either calorie-restricted diets or what is known as "habitual" diets (in which a participant follows their usual diet).

They found that those participants who ate dairy in studies that required them to reduce their caloric intake were more successful at weight loss than those who ate dairy and followed their usual diet. Similarly, those who ate dairy and reduced their caloric intake also lost significantly more body fat than those who ate dairy and followed their usual diet.

That said, when the researchers compared studies of shorter duration (less than 1 year) with longer studies (over 1 year), they saw that while body fat decreased in the shorter, calorie-restricted studies, for longer studies the amount of body fat actually increased.

What this means for you

Weight loss is not about short-term solutions, nor is it about dieting (in the sense of restricting calories). The most successful eating plan is one that you can sustain over the long term, and the results of this study show that increasing your dairy intake is unlikely to help you achieve long-term weight control. Don't worry about which foods are going to make your weight loss easier - focus on following a healthy diet for the long haul.

First posted: October 3, 2012