Saturated Fat Beats Out Carbs: Tripling Saturated Fat Intake Leaves No Effect In Blood

Saturated Fat
Saturated fat in your diet need necessarily increase heart health, a new meta-analysis finds. Scott Henderson, CC by 2.0

Nutrition experts advise against food high in saturated fat not only because of a high calorie content, but also because of an overall rise in the level of cholesterol in our blood. A recent study supported by the Dairy Research Institute, the National Cattlemen's Beef Association, and the Egg Nutrition Center has found that doubling or even tripling the amount of saturated fat in our diets will not lead to increases of total saturated fat in our blood.

"People believe 'you are what you eat,' but in reality, you are what you save from what you eat," Jeff Volek, a professor of human sciences at The Ohio State University, said in a statement. "The point is you don't necessarily save the saturated fat that you eat. And the primary regulator of what you save in terms of fat is the carbohydrate in your diet. Since more than half of Americans show some signs of carb intolerance, it makes more sense to focus on carb restriction than fat restriction."

Volek and his colleagues provided 16 adults suffering from metabolic syndrome with the same diet consisting of 2,500 calories and 130 grams (g) of protein a day for a period of 18 weeks. People with metabolic syndrome are affected by at least three out of five risk factors for heart disease and diabetes, including excess belly fat, elevated blood pressure, low "good" cholesterol, insulin resistance or glucose intolerance, and high triglycerides. Diets started with 47g of carbs and 84g of saturated fat per day at the beginning of the study and ended with 346g of carbs and 32g of saturated fat per day.

By the end of the study, the average participant lost around 22 pounds and experienced significant improvements in blood glucose, insulin, and blood pressure. Total saturated fat in the blood did not increase in any of the participants and even went down for some. Researchers also tracked the levels of palmitoleic acid, a fatty acid linked to an unhealthy metabolism of carbs that can promote disease. Although palmitoleic acid levels decreased on high-fat/low-carb diets, concentrations of this fatty acid in the blood increased as carbs were added to the diet.

"There is widespread misunderstanding about saturated fat. 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," Volek added. "But studies measuring saturated fat in the blood and risk for heart disease show there is an association. Having a lot of saturated fat in your body is not a good thing. The question is, what causes people to store more saturated fat in their blood, or membranes, or tissues?

According to the American Heart Association, saturated fats occur naturally in meat and dairy products, such as fatty beef, lamb, pork, poultry with skin, beef fat, lard and cream, butter, cheese, and whole or reduced fat milk. The AHA recommends a diet that derives five to six percent of calories from saturated fat. On average, our diet should consist of 13g of saturated fat each day.

Source: Volk B, Kunces L, Volek J, et al. Effects of Step-Wise Increases in Dietary Carbohydrate on Circulating Saturated Fatty Acids and Palmitoleic Acid in Adults with Metabolic Syndrome. PLOS ONE. 2014. 

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