Whole Milk vs. Skim Milk

A dear friend and college roommate informed me that her husband recently switched to whole milk because he read that it was healthier. Seeing as this runs contrary to decades of dietary advice, she asked for my opinion on the matter.

Emerging Research on Milk Fat

While saturated fat (the main type of fat in animal foods, including whole milk) is largely considered a dietary villain, emerging research is shedding new light on the dairy debate.

Skim vs Whole Milk

The article in question references a study in which whole milk drinkers were found to weigh less than skim milk drinkers, a surprise, considering a cup of whole milk has nearly double the calories (150 vs 80) of skim milk, due to an additional 8g of total fat (5g saturated fat). However, this is not the first instance of high calorie foods being associated with lower body weights. Nuts and seeds are high in calories, but also high in fiber and heart healthy unsaturated fats, meaning that they fill you up and provide lasting energy. The idea behind both of these paradoxes is that low fat diets are unsatisfying, and often urge us to overcompensate in calories elsewhere. But even though fat is a healthy, essential nutrient, not all fats are created equal.

A recent article from Tricia Ward cites “increasing evidence that dairy fats do not increase [Cardiovascular Disease] risk and may even lead to a better metabolic profile,” due to their unique odd-chain saturated fatty acids. Dairy fats are also shown to be less harmful than margarine, which is a highly processed solid fat made from hydrogenated oils, a manmade process that creates dangerous trans-fats. Additionally, some researchers find that when saturated fats are replaced with refined carbohydrates and added sugars, heart disease risk increases, making saturated fats appear to be a healthy choice.

For these reasons, Dr. Dariush Mozaffarian, the dean of the nutrition school at Tufts University, finds it “absurd” that the school lunch program allows sweetened nonfat chocolate milk, but not whole milk. After all, cutting back on dairy fat means increasing other nutrients, which in the case of added sugar, is certainly a step in the wrong direction.

However, what fails to make headlines in the debate about dairy fat is that when saturated fat is replaced with unsaturated fat in the form of olive oil, sunflower oil, nuts, or avocados, heart disease risk actually decreases. So while butter and milkfat may be dubbed the lesser of two evils (when compared to added sugars), the goal of healthful eating should be to find foods that are proven to actually nourish you and prevent disease, rather than picking foods simply because they are “not as bad as” others. (To learn more about the saturated fat debate, see this blog post.)

Current Recommendations

Fat is an essential nutrient, and health experts generally agree that a low fat or no fat diet is not the answer to health. That being said, reputable nutrition organizations, including the Harvard School of Public Health, the American Heart Association, and the 2015 Dietary Guidelines Advisory Committee all recommend switching from full fat dairy to reduced fat or nonfat dairy, in order to reduce the intake of saturated fats.

As Walter Willett and Frank Hu (of the Harvard School of Public Health) suggest in a recent Boston Globe article, dietary guidelines are (and always will be) a work in progress, based on a consensus of the latest scientific evidence. The emerging research described above (and in Tricia Ward’s article) offers fascinating new insights on the unique role of whole milk and dairy fat, but there is still not enough evidence (nor is there a scientific consensus) for nutrition experts to recommend making a switch to full fat dairy products.

According to the 2015 Dietary Guidelines Advisory Committee report, which was just released on February 19th, “Nutrient intake data, together with nutritional biomarker and health outcomes data indicate that sodium and saturated fat are overconsumed and may pose a public health concern.” The committee “recommend[s] consumption of low-fat and fat-free foods in the Dairy group to ensure intake of these key nutrients while minimizing intake of saturated fat.”

Similarly, these are the recommendations from the Harvard School of Public Health:

Limit your intake of saturated fats by cutting back on red meat and full-fat dairy foods. Try replacing red meat with beans, nuts, poultry, and fish whenever possible, and switching from whole milk and other full-fat dairy foods to lower fat versions, or just eating smaller amounts of full-fat dairy products, such as cheese. Don’t replace red meat with refined carbohydrates (white bread, white rice, potatoes, and the like).

According to NYU nutrition professor and public health expert Marion Nestle, “It isn’t necessary to get into as yet unanswerable questions of heart disease or cancer to decide what to do about dairy foods. The calories and saturated fat are reason enough to choose lower-fat options.”

If there is a general scientific consensus that animal fats should be minimized, then why might journalists suggest that whole milk and butter can keep us trim and healthy? The Harvard School of Public Health offers this explanation:

Many dairy products are high in saturated fats, and a high saturated fat intake is a risk factor for heart disease. And while it’s true that most dairy products are now available in fat-reduced or nonfat options, the saturated fat that’s removed from dairy products is inevitably consumed by someone, often in the form of premium ice cream, butter, or baked goods. Strangely, it’s often the same people who purchase these higher fat products who also purchase the low-fat dairy products, so it’s not clear that they’re making great strides in cutting back on their saturated fat consumption.

Skim Milk vs Whole MilkThe Organic Factor

Whether or not your milk is organic or from grass fed cows can also have a large impact on the nutrition composition of the milk, especially the makeup of the fats. Research shows that whole organic milk from grass-fed cows is a higher (by 62%) in omega-3 fatty acids than conventional whole milk. Omega-3 fatty acids are an essential fat with several documented health benefits, which means that whole milk from organic, grass-fed dairy products may actually offer some modest health benefits not seen in nonfat dairy. (To learn more about why I choose organic dairy, see this blog post.)

The Bottom Line

The research surrounding odd-chain saturated fatty acids (the special kind found in dairy) is still new, so we don’t yet know just how much it differs from other animal fats with regards to health benefits and risks. However, what we do know is that Americans consume too many calories, and too much saturated fat and added sugars. We also know that replacing animal fat with fats from plant sources (like nuts, seeds, avocados, olive oil, sunflower oil, flax, etc.) has been shown to offer all of the health benefits of fat, without the health risks still linked to animal fats.

Food choices are, of course, largely personal. And because all foods offer a mix of different fats, saturated fats are impossible to avoid completely. I choose unsweetened, organic nonfat or reduced fat dairy products (except for flavorful, full fat cheese that I use as a garnish on salads and other dishes), and supplement my diet with an ample amount of fatty plant foods in the form of flaxseed, peanut butter, almonds, avocado, and olive oil. Do you eat dairy products? What kind of milk do you buy?

– Kelly