For decades, Americans have been nudged toward skim milk and low-fat yogurt to protect their waistlines and blood lipids. A new randomized controlled trial from the University of Toronto pushes back on that received wisdom.
Over 12 weeks, adults with overweight or obesity who ate three daily servings of full-fat dairy showed no meaningful change in weight, body fat, or cholesterol compared with a low-dairy group, according to the trial published in The Journal of Nutrition.
The 74 participants were split across three plans. One group ate a low-dairy diet with calorie restriction. The other two ate three daily servings of full-fat dairy, one calorie-controlled and one unrestricted. All three otherwise followed Canada's food guide.
"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 in the Department of Nutritional Sciences at the University of Toronto's Temerty Faculty of Medicine, who led the study.
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What the trial actually measured
Beyond the neutral effects on weight and lipids, the full-fat dairy groups also had lower blood pressure. Their intakes of calcium, protein, and vitamin D were higher than the low-dairy group. Those are nutrients many Americans routinely fall short on.
The researchers credit the so-called dairy matrix. The idea is that dairy delivers saturated fat wrapped inside a package of proteins, minerals, and other bioactive compounds, which appears to blunt the cholesterol response you would expect from an equivalent dose of isolated fat.
"With dairy products, it's got two proteins, casein and whey, that are bound together with fat and with nutrients mixed in," Anderson explained.
Where US guidance now stands
Federal advice has recently shifted in the same direction. The 2025-2030 Dietary Guidelines for Americans, released in early January 2026, recommend three daily servings of dairy and, for the first time in decades, treat whole and reduced-fat versions as acceptable within a healthy pattern. The 10 percent cap on saturated fat as a share of daily calories still stands.
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Not everyone is convinced the new framing is coherent. Frank Hu, chair of the Department of Nutrition at the Harvard T.H. Chan School of Public Health, warned that "the mixed messages surrounding saturated-fat-rich foods such as red meat, butter, and beef tallow may lead to confusion and potentially higher intake of saturated fat and increased LDL cholesterol and cardiovascular risk."
Read the small print
The Toronto trial was funded by Dairy Research Cluster 3, a joint program of Canadian government agencies and the dairy industry. The sample was small at 74 adults and the follow-up short at 12 weeks, so no trial of that size can settle long-term cardiovascular risk on its own.
Anderson's own takeaway is deliberately unfussy. "Keep it simple, eat a variety of foods and not too much of anything," he said. For most people, that means whole milk yogurt or full-fat cheese can sit alongside skim as part of a balanced diet. Anyone managing high cholesterol or heart disease should still talk to their doctor before rewiring the dairy shelf.
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