Ohio State University find that levels of fat in the blood did not increase with a high fat diet, but did with a high carbohydrate intake
By Sarah Knapton
21 November 2014
Saturated fat has long been demonised by doctors and nutritionists who claim that it increases the risk of heart problems.
But decades of official advice may need to be altered, after new research suggested that it may be safe to eat up to three times the maximum amount currently recommended by the NHS.
It means that far from being foods to avoid, butter, cheese, meat and cream, could all form part of a healthy lifestyle.
NHS advice is unequivocal on saturated fat, with guidance stating that it raises the level of cholesterol in the blood and increases the risk of heart disease.
However when researchers at Ohio State University asked volunteers to try out different diets they were surprised to find that raising the intake of saturated fat did not increase fat in the blood. It seems that the body burns up saturated fat quickly as energy.
In contrast, when the level of carbohydrate was raised, dangerous fatty acids did increase in the bloodstream. These have been linked to Type 2 diabetes and heart disease.
Senior author Jeff Volek, professor of human sciences at Ohio State University said the findings ‘challenge the conventional wisdom that has demonised saturated fat.’
“When you consume a very low-carb diet your body preferentially burns saturated fat,” Volek said.
“We had people eat two times more saturated fat than they had been eating before entering the study, yet when we measured saturated fat in their blood, it went down in the majority of people. Other traditional risk markers improved, as well.”
Saturated fat is the kind of fat found in butter and lard, pies, cakes and biscuits, fatty cuts of meat, sausages and bacon, and cheese and cream.
NHS guidelines state that the average man should eat no more than 30g of saturated fat in a day, and the average woman no more than 20g. A steak contains around 27g, a slice of cheese around 5g and butter on toast would be around 7g.
However even when participants were eating high fat dies which comprised 84g of fat per day, the fat levels in the blood did not rise. Cholesterol levels also did not change. In contrast when they moved towards guideline levels of saturated fat, and increased carbohydrate intake, the levels of Palmitoleic acid, a fatty acid, in the bloodstream rose.
High levels of Palmitoleic acid have been linked to obesity and higher risk for inflammation, insulin resistance, impaired glucose tolerance, metabolic syndrome, type-2 diabetes, heart disease and prostate cancer.
“There is widespread misunderstanding about saturated fat,” added Professor Volek.
“In population studies, there’s clearly no association of dietary saturated fat and heart disease, yet dietary guidelines continue to advocate restriction of saturated fat. That’s not scientific and not smart.
“People believe ‘you are what you eat,’ but in reality, you are what you save from what you eat,” he said. “The point is you don’t necessarily save the saturated fat that you eat.”
The study adds to a growing body of evidence that suggests that saturated fat may not be as dangerous as previously feared.
In March, researchers at Cambridge University have found that giving up fatty meat, cream or butter is unlikely to improve health.
The team, whose results appear in the journal Annals of Internal Medicine, conducted a “meta-analysis” of data from 72 studies involving more than 600,000 participants from 18 countries.
A key finding was that total saturated fat, whether measured in the diet or the bloodstream, showed no association with heart disease.
Earlier this year Dr James DiNicolantonio of Ithica College, New York, called for a new public health campaign to admit ‘we got it wrong.’ He claims carbohydrates and sugar are more responsible.
Naveed Sattar, professor of metabolic medicine at the University of Glasgow, said: “Levels and types of saturated fats in the blood appear to be governed by more than just saturated fat intake and that factors like carbohydrate intake also matter.
“Current evidence favours folk taking less refined carbohydrate and less saturated fat. Evidence also suggests that if one is interested in losing weight, it does not matter what type if diet one undertakes – low fat vs low carbohydrate so long as one sticks to diet so they key is for folk to find a diet or diet mix they can sustain and enjoy.”
The research was published in the journal PLOS One.