For decades, health guidelines have told people to reach for low-fat or fat-free dairy. A new study from the University of Toronto suggests that advice may need a closer look.
Researchers found that adults who ate three servings of full-fat dairy per day for 12 weeks showed no meaningful increases in body weight, body fat, cholesterol, or insulin resistance. The study was published in The Journal of Nutrition, according to Science Daily.
The study enrolled 74 adults with overweight or obesity and divided them into three groups. One group followed a low-dairy, calorie-restricted diet. A second group followed an energy-neutral diet that included three servings of full-fat dairy each day. A third group ate an unrestricted diet that also included three daily dairy servings. All participants received guidance on following Canada's food guide, and those in the dairy groups were supplied with full-fat products during the study.
After 12 weeks, the researchers found no significant differences in weight gain, body composition, or cholesterol levels between the low-dairy group and the groups consuming three dairy servings per day. The dairy groups also showed improvements in blood pressure and took in more calcium, protein, and vitamin D.
"Those that had three servings of dairy didn't have adverse levels of blood cholesterol or lipids or evidence of insulin resistance," said Harvey Anderson, a professor of nutritional sciences at U of T's Temerty Faculty of Medicine who led the study.
The traditional concern about full-fat dairy centers on its saturated fat content. Saturated fat has long been linked to higher cholesterol and increased cardiovascular risk, which is why dietary recommendations in Canada and many other countries have pushed lower-fat options.
Anderson said the evidence from human studies has not always matched those concerns. Numerous studies have found no connection between eating full-fat dairy and harmful health outcomes. Some research has even reported protective effects. Anderson pointed to recent work by Temerty Medicine professor Kozeta Milliku as an example of findings that lean in a positive direction.
The University of Toronto study adds to a growing body of research suggesting that how a food is structured may matter as much as the individual nutrients it contains. Dairy foods are complex, containing fats, proteins, carbohydrates, and minerals in a form that may behave differently in the body than isolated saturated fat does on its own.
The findings do not suggest that unlimited full-fat dairy is without consequence, but they do raise questions about whether blanket recommendations against it are supported by current evidence.
