A new Canadian study uncovers evidence to the contrary, finding that consuming three daily servings of full-fat dairy neither increased body fat nor raised cholesterol levels.
Consumers have been told for decades to choose fat-free or low-fat dairy products to protect their hearts and waistlines. But a new Canadian study uncovers evidence to the contrary, finding that consuming three daily servings of full-fat dairy neither increased body fat nor raised cholesterol levels.
The study, published in the Journal of Nutrition, followed 74 adults with overweight or obesity for 12 weeks. Researchers found that participants who consumed three daily servings of full-fat dairy experienced no meaningful increases in body weight, body fat, cholesterol, blood lipids, or markers of insulin resistance compared to those following a lower-dairy diet.
Instead, the higher dairy intake was associated with several positive outcomes, including improved blood pressure and greater intake of key nutrients such as calcium, protein, and vitamin D.
"Those who had three servings of dairy didn't have adverse levels of blood cholesterol or lipids or evidence of insulin resistance," says Harvey Anderson, a professor of nutritional sciences in the University of Toronto's Temerty Faculty of Medicine and lead researcher on the study.
For years, dietary guidelines in the US, Canada and elsewhere have encouraged people to select low-fat or fat-free dairy products because of their saturated fat content. Saturated fat has traditionally been linked to elevated cholesterol and a greater risk of cardiovascular disease.
However, Anderson notes that real-world human studies have painted a much different picture.
Numerous clinical and observational studies have found little or no association between full-fat dairy consumption and negative health outcomes. In fact, some research has even reported protective health benefits associated with dairy intake, suggesting that dairy foods may behave differently than would be predicted based on their saturated fat content alone.
One explanation is known as the dairy matrix hypothesis. Rather than evaluating dairy based solely on the amount of saturated fat it contains, researchers are increasingly looking at how the food's natural structure influences the way nutrients are absorbed and used by the body.
"With dairy products, it's got two proteins - casein and whey - that are bound together with fat and with nutrients mixed in," Anderson says, adding that it's this unique and complex physical structure that is responsible for the slow and steady delivery of nutrients from dairy products, and that expands their health impacts to more than just the sum of the isolated nutrients.
In other words, cheese, yogurt, and milk are much more than simply sources of saturated fat. Their unique combination of proteins, fats, vitamins, and minerals appears to influence digestion and metabolism in ways that may help explain why full-fat dairy has consistently shown neutral—or even beneficial—effects on body weight and heart health in many human studies.
The findings may be especially important for older adults, who often struggle to consume enough protein and essential nutrients while eating fewer calories overall. Full-fat dairy provides a convenient source of high-quality protein, calcium, vitamin D, and other nutrients without appearing to increase the risk of obesity, diabetes, or cardiovascular disease.
More broadly, the research reinforces the idea that foods should be evaluated as complete packages rather than by focusing on a single nutrient like saturated fat. As scientists continue to study whole foods instead of isolated nutrients, long-standing assumptions about foods such as full-fat dairy may continue to evolve.
For consumers trying to navigate conflicting nutrition advice, Anderson offers a simple reminder:
"Keep it simple, eat a variety of foods and not too much of anything."
