Full-fat milk, cheese and dairy every day? Canadian study delivers surprising findings on weight and cholesterol

For years, people have been told to choose low-fat or fat-free dairy to limit saturated fat. But a new Canadian study has found that eating three servings of full-fat dairy every day did not cause weight gain or raise cholesterol levels over 12 weeks.

A Canadian study involving 74 adults with overweight or obesity has challenged a long-standing assumption about full-fat dairy, finding that consuming three daily servings for 12 weeks did not negatively affect body weight, body composition, energy metabolism or blood lipid levels.

The research, led by University of Toronto professor Harvey Anderson, also found that participants who consumed more dairy recorded improvements in blood pressure and had higher intakes of calcium, protein and vitamin D.


The findings were published in The Journal of Nutrition.

What happened when participants ate full-fat dairy every day?

Researchers randomly divided the 74 participants into three groups.

One group followed a calorie-restricted, low-dairy diet. A second group followed an energy-neutral diet that included three servings of dairy each day. The third group was allowed to eat without energy restrictions but was also asked to consume three servings of dairy daily.

Participants were advised to follow Canada's Food Guide and were provided with full-fat dairy products.

After 12 weeks, researchers found no meaningful differences in weight gain, body composition or cholesterol levels between people following the low-dairy diet and those consuming three servings of dairy each day.

However, the groups consuming more dairy recorded lower blood pressure and increased their intake of important nutrients, including calcium, protein and vitamin D.

Why are these findings surprising?

Full-fat dairy has traditionally faced criticism because it contains saturated fat. Dietary guidance has often encouraged consumers to choose low-fat or fat-free dairy products to reduce saturated fat intake, which has been associated with elevated cholesterol and cardiovascular disease risk.

But Anderson said the relationship between full-fat dairy and health may be more complicated than simply looking at its saturated fat content.

According to him, numerous human studies have not found a clear association between consuming full-fat dairy and negative health outcomes. Some research has also reported neutral or potentially beneficial effects.

One possible explanation is known as the dairy matrix hypothesis.

The theory suggests that the physical structure of a whole dairy food can influence how its nutrients are digested and absorbed. As a result, the effect of consuming a whole dairy food may differ from what would be expected by examining individual nutrients in isolation.

“With dairy products, it’s got two proteins — casein and whey — that are bound together with fat and with nutrients mixed in,” Anderson explained.

He said this complex structure may allow nutrients to be delivered more slowly and steadily, potentially affecting how the body responds to dairy.

Could full-fat dairy be useful for older adults?

The findings could have particular relevance for older people, who may need fewer calories but still require adequate amounts of protein and essential nutrients.

Dairy products can provide protein, calcium and vitamin D in a relatively compact food source. This could make them a practical option for older adults who struggle to consume enough nutrients while having lower overall energy requirements.

The researchers said the findings also highlight a broader issue in nutrition research: foods should not necessarily be judged solely by one nutrient.

Does the study mean you should switch to full-fat dairy?

Not necessarily.

The study was relatively small, involving only 74 adults, and lasted for 12 weeks. It therefore does not establish the long-term health effects of consuming full-fat dairy or prove that full-fat dairy is healthier than low-fat alternatives.

Instead, the findings add to growing research suggesting that the health effects of whole foods can be more complicated than the effects of individual nutrients.

The study's results challenge the assumption that consuming full-fat dairy automatically leads to weight gain or higher cholesterol, but they do not mean that everyone should increase their dairy intake.

Anderson's advice amid constantly changing nutrition trends was straightforward: “Keep it simple, eat a variety of foods and not too much of anything.”

The research was supported by Dairy Research Cluster 3 under the Canadian Agricultural Partnership AgriScience Program and the Mitacs Accelerate program.