Foods high in saturated fat, such as cheese and cream, may actually improve health and reduce the risk of obesity, heart disease and diabetes, according to a study conducted by researchers from the University of Bergen, Norway, and published in the American Journal of Clinical Nutrition.
The findings contradict previously held wisdom — that a diet high in saturated fat increases the risk of obesity and metabolic diseases — but are in keeping with more recent research on the topic. “There is a tremendous focus on avoiding high-fat foods for weight control but this study challenges the notion that saturated fats have a strongly negative impact on health and weight,” researcher Simon Dankel said.
“The men on a high fat diet not only lost weight but also became slimmer and had lower cholesterol levels.”
The study was conducted on 38 men with abdominal obesity, who were assigned to follow a diet either rich in fat or in mostly unrefined carbohydrates. Researchers measured the participants’ cardiovascular risk factors, along with fat around the abdomen, liver and heart.
Both diets contained similar amounts of calories, protein and polyunsaturated fats (from vegetable oils other than olive oil). Both diets were very low in refined sugar. Fats in the study came mostly from minimally processed sources such as cheese, cream, butter and coconut oil. Neither diet contained highly refined oils, margarine or trans fats.
Men in both groups lost weight and showed dramatic reductions in the risk factors for cardiovascular disease, Type 2 diabetes and cancer. This contradicts official dietary advice, which predicts that the unrefined carbohydrate group would show health improvements, whereas the health of the high-fat group would worsen.
“The very high intake of total and saturated fat did not increase the calculated risk of cardiovascular diseases,” researcher Ottar Nygård said.
Specifically, the men in the high-fat group saw reductions in their blood pressure, insulin, blood glucose, blood lipids, and ectopic fat storage.
All the improvements were seen even in men who increased their total calorie intake.
The findings suggest that nutrition science may have been missing the point in its focus on individual nutrients, the researchers said.
“Our findings indicate that the overriding principle of a healthy diet is not the quantity of fat or carbohydrates, but the quality of the foods we eat,” said researcher Johnny Laupsa-Borge.
The scientists emphasized that the men’s health improved because they were eating a good diet made up of real, unprocessed foods. It’s possible–but would need to be confirmed–that prior studies found that saturated fat was bad for health because they were studying people with an unhealthy diet overall.
“We here looked at effects of total and saturated fat in the context of a healthy diet rich in fresh, lowly processed and nutritious foods, including high amounts of vegetables and rice instead of flour-based products,” researcher Vivian Veum said. “The fat sources were also lowly processed, mainly butter, cream and cold-pressed oils.”
Also contradicting conventional nutritional wisdom, there was no increase in levels of LDL (“bad”) cholesterol among those on the high fat diet. Levels of HDL (“good”) cholesterol did increase.
“These results indicate that most healthy people probably tolerate a high intake of saturated fat well, as long as the fat quality is good and total energy intake is not too high. It may even be healthy,” Ottar Nygård said.
A number of studies in recent years have begun to undermine the previous consensus on saturated fat. A National Institutes of Health study published in the British Medical Journal in early 2016 showed that people who replaced saturated fat with polyunsaturated fat showed no change in heart disease risk.
This echoed the findings of a 2015 British Medical Journal review into 50 studies into the connection between saturated fat, trans fats and health outcomes. That study showed no evidence that saturated fats were bad for health. In contrast, it showed overwhelming evidence that trans fats (an industrially manufactured product) are highly dangerous.