University of Toronto Study Finds Full-Fat Dairy Does Not Raise Cholesterol or Weight

Researchers at the University of Toronto conducted a 12-week randomized controlled trial to test the effects of full-fat dairy consumption on metabolic health markers. The study, published in The Journal of Nutrition, enrolled 74 overweight or obese adults and assigned them to one of three dietary groups: a low-dairy diet with calorie restriction, an energy-neutral diet with three daily servings of full-fat dairy, or an unrestricted diet with three daily servings of full-fat dairy.

Participants in the dairy groups were provided with full-fat dairy products and counseled to follow Canada's Food Guide. After 12 weeks, researchers observed no meaningful differences in body weight, body composition, or blood cholesterol levels between the low-dairy group and either of the full-fat dairy groups.

Lead researcher Professor Harvey Anderson of the Faculty of Medicine reported that participants consuming three daily servings of full-fat dairy showed no adverse changes in blood lipids or evidence of insulin resistance. The dairy groups also experienced improvements in blood pressure compared to baseline.

The dairy-consuming groups had higher intakes of calcium, protein, and vitamin D. Anderson noted that these findings are particularly relevant for older adults, who often have lower energy needs but require nutrient-dense foods to meet protein and micronutrient requirements without increasing chronic disease risk.

The researchers suggest the results may be explained by the dairy matrix hypothesis, which proposes that the physical structure of dairy foods — where proteins such as casein and whey are bound with fat and nutrients — affects digestion and nutrient delivery in ways that differ from isolated saturated fats.

The study was supported by the Dairy Research Cluster 3 under the Canadian Agricultural Partnership AgriScience Program. Anderson emphasized that the findings support evaluating nutrition through a whole-food lens rather than focusing on single nutrients such as saturated fat.

The trial's relatively small sample size and 12-week duration limit the strength of long-term conclusions. The authors note that further research is needed to confirm these effects in broader populations and over extended periods.