The belief that saturated fat in foods such as butter, cheese and meat clogs arteries is "just plain wrong," a group of cardiologists say in a new editorial.
Instead, the focus should be on eating a Mediterranean-style diet, taking a brisk walk daily and minimizing stress, they say.
After decades of thinking that cutting saturated fat in the diet was associated with lowering the risk of cardiovascular disease, Type 2 diabetes and death, doctors and researchers now realize there is no association in healthy adults.
Even in people with established heart disease, reducing saturated fat alone doesn't reduce heart attacks, says British cardiologist Dr. Aseem Malhotra, of Lister Hospital, and an adviser to the U.K. national obesity forum.
Malhotra said he and his co-authors wrote the editorial, published in Wednesday's online issue of the British Journal of Sports Medicine, to shift the narrative and address the root causes of heart disease.
"One thing that's very clear when you look at the totality of the evidence: saturated fat does not clog the heart arteries. And sadly, for many years — for decades, in fact — this has been the primary focus of treatment of heart disease and public health advice," Malhotra said in an interview.
As a result of warnings about saturated fat, some people shifted their diets towards carbohydrates. But an excess of processed carbs and refined carbs also plays a part in developing cardiovascular diseases.
Eating too much white bread, pasta and potatoes raises blood glucose rapidly, Malhotra said. Our bodies respond to those carbs by producing too much insulin.
When insulin levels are chronically high, the hormone stops being able to do its job of getting glucose into cells to provide energy.
When the body becomes resistant to insulin, an inflammatory response is triggered, said cardiologist Dr. Michael Farkouh, who is the chair of multinational clinical trials at the Peter Munk Cardiac Centre at Toronto General Hospital and was not involved in the editorial.
"What this editorial really brought to light was that your diet, if it's a diet rich in carbohydrates, can be associated with what's called insulin resistance," Farkouh said. "That allows your innate inflammatory process in the body to attack the vessel wall and start the process of hardening of the arteries."
A dietary imbalance of nutrients, over time, can damage the arteries.
"It's the lipid or fat, soft plaque that's vulnerable to rupturing. And that's what causes the sudden problem of a heart attack," Farkouh said.
A 'whole dietary approach'
Ross Durant, 84, became Farkouh's patient when he had a heart attack in 2012. At the time, Durant was at least 20 pounds overweight and had Type 2 diabetes.
"I would drink more than [doctors] suggested I should because I do enjoy martinis," Durant recalled. "I was sneaking a bit of ice cream, which I shouldn't. My big cheat: I eat butter."
Durant appreciates butter is no longer considered a "cheat." Now, his typical dinner is half a plate of vegetables, a protein and a carbohydrate — and a dab of butter.
Rather than focus on one nutrient, we should eat whole foods prepared at home with as natural ingredients as possible, said Russell de Souza, a registered dietitian and nutrition epidemiologist at McMaster University in Hamilton.
De Souza recommends a Mediterranean-style diet rich in nuts, oily fish, seeds, with plenty of fibrous vegetables and protein such as grilled chicken or tofu.
"I think this movement away from a focus on a specific nutrient, looking towards a whole dietary approach, is certainly a step in the right direction," de Souza said.
In the U.K., some physicians and researchers said the editorial failed to highlight contradictory research, such as a rigorous Cochrane systematic review that concluded that cutting down dietary saturated fat was associated with a 17 per cent reduction in cardiovascular events, based on 15 randomized trials offering the highest quality medical evidence.
When dining out, de Souza's No. 1 tip is to put half of your plate in a takeout container as soon as you're served because the portion sizes tend to be so high.
"Things like exercise, eating as healthfully as we can, trying to minimize our stress through meditation are ways to prevent heart disease without focusing on a particular mechanism that may or may not be outdated," he said.
The editorial authors say taking a holistic approach of walking 20 to 30 minutes a day and eating "real food" can reduce heart disease. "There is no business model or market to help spread this simple yet powerful intervention," they concluded.