Full-fat dairy does not harm metabolism, study finds

A major new study challenges decades of advice by finding that eating full-fat dairy daily does not harm weight, cholesterol or metabolism—contradicting long-held warnings that low-fat versions were healthier.

For years, nutrition guidelines told people to swap whole milk, cream and cheese for low-fat yogurt and skimmed milk to fight obesity and heart disease. But a team led by Harvey Anderson at the University of Toronto has now shown that three daily servings of full-fat dairy left adults’ body weight, body fat, blood fats and insulin levels unchanged after 12 weeks. The work, published in The Journal of Nutrition, joins a growing body of research questioning the saturated-fat warning.

In the trial that ran from late 2020 to early 2023, 74 adults with overweight or obesity were split into three groups: one ate little dairy and cut calories, a second ate three daily servings of full-fat dairy without changing calories, and a third ate three servings freely. Only the full-fat group showed slight improvements in blood pressure and higher intake of calcium, protein and vitamin D. Anderson told ScienceDaily that “those with three servings of dairy did not show adverse cholesterol, lipids or insulin resistance.” The findings clash with current US and Canadian recommendations for three low- or no-fat dairy servings per day.

The old logic was simple: saturated fat raises LDL cholesterol, so cutting fat should cut heart risk. Saturated fat does raise LDL, and replacing it with unsaturated fats from nuts, seeds and vegetable oils does lower cardiovascular risk. Yet large analyses, including a 2016 Harvard study of more than 220,000 adults, have found dairy fat itself is not linked to higher heart disease. Experts now say the blanket advice to avoid full-fat dairy may have oversimplified a complex picture. The new research suggests that, for many people, moderate full-fat dairy can fit into a balanced diet without the drawbacks once assumed.