For decades we avoided full-fat dairy — new study finds no downside

A new Canadian study led by University of Toronto professor Harvey Anderson adds to a growing body of evidence suggesting that full-fat dairy can fit into a healthy diet. Over 12 weeks, 74 adults consumed different amounts of dairy while following varying dietary plans. The researchers found that eating three servings of full-fat dairy daily caused no meaningful harm to body weight, body composition, energy metabolism or blood lipid levels. The results were recently published in The Journal of Nutrition.

Why full-fat dairy raised concerns

Dairy contains saturated fat, long linked to higher cholesterol and greater cardiovascular risk, which is why dietary guidelines in Canada and elsewhere have generally recommended fat-free or low-fat dairy. However, Anderson notes that human research has not always supported these concerns: many studies found no link between full-fat dairy and negative health outcomes, and some, including work led by fellow Temerty Medicine professor Kozeta Milliku, even pointed to protective effects.

Testing three daily servings

The study randomly assigned 74 adults with overweight or obesity to three groups: a calorie-restricted, low-dairy diet; an energy-neutral diet with three daily dairy servings; and an unrestricted diet also including three daily servings. All followed Canada's food guide, and dairy-group participants received full-fat products. After 12 weeks, there were no meaningful differences in weight gain, body composition or cholesterol between the low-dairy group and those eating three servings a day. Those consuming more dairy showed improved blood pressure and higher intakes of calcium, protein and vitamin D, with no signs of adverse cholesterol, lipid levels or insulin resistance.

A possible explanation: the dairy matrix

Anderson suggests the apparent mismatch between saturated fat's expected harms and dairy's neutral or beneficial effects may be explained by the "dairy matrix hypothesis" — the idea that a food's physical structure affects how its nutrients are digested and absorbed. In dairy, the proteins casein and whey are bound with fat and other nutrients, allowing gradual nutrient delivery to the body.

Relevance for older adults

Anderson says the findings could matter especially for older adults, who need less energy but may struggle to get enough protein and other nutrients. Dairy, already familiar to many, could offer a practical way to meet those needs without raising chronic disease risk. The study was funded by Dairy Research Cluster 3 under the Canadian Agricultural Partnership AgriScience Program and the Mitacs Accelerate program.