Doubling or even nearly tripling saturated fat in the diet does not drive up total levels of saturated fat in the blood, according to a controlled diet study.
According to senior author Prof. Jeff Volek, the study, "challenges the conventional wisdom that has demonized saturated fat and extends our knowledge of why dietary saturated fat doesn't correlate with disease."
In the study, published in PLOS ONE, the authors state that current dietary guidelines in the US recommend the majority of calories should be acquired from carbohydrates, with only 7-10% of total energy coming from saturated fats.
The finding "challenges the conventional wisdom that has demonized saturated fat and extends our knowledge of why dietary saturated fat doesn't correlate with disease," said senior author Jeff Volek, a professor of human sciences at The Ohio State University.
It's unusual for a marker to track so closely with carbohydrate intake, making this a unique and clinically significant finding. As you increase carbs, this marker predictably goes up," Volek said.
The researchers found that total saturated fat in the blood did not increase - and went down in most people - despite being increased in the diet when carbs were reduced. Palmitoleic acid, a fatty acid associated with unhealthy metabolism of carbohydrates that can promote disease, went down with low-carb intake and gradually increased as carbs were re-introduced to the study diet.In the study, participants were fed six three-week diets that progressively increased carbs while simultaneously reducing total fat and saturated fat, keeping calories and protein the same.
To achieve this, foods containing saturated fat - beef, eggs, high-fat dairy products - should be limited. Typically, a reduction in these foods results in an increased consumption of carbohydrates.
"People believe 'you are what you eat,'" says Prof. Volek, "but in reality, you are what you save from what you eat. The point is you don't necessarily save the saturated fat you eat. And the primary regulator of what you save in terms of fat is the carbohydrate in your diet."
