Saturated fat builds more fat than polyunsaturated fat, study shows

Saturated fat builds more fat and less muscle compared to polyunsaturated fat, a new study found.

The findings are unique in that it shows the fat consumption in foods not only affects cholesterol levels and risk for cardiovascular disease, but also determines where fat will be stored in the body.

The study involved almost 40 men and women who consumed an extra 750 calories every day for seven weeks in an effort to gain an additional 3 percent of their body weight.

Researchers chose at random participants to eat either muffins from polyunsaturated fat (sunflower oil) or saturated fat (palm oil) as their means for gaining surplus calories, while sugar, carbohydrate, fat and protein content remained the same.

Using MRI scanning to determine fat distribution and muscle mass, researchers found that even though people in both groups gained about the same amount of weight, those consuming more saturated fat had a greater increase in the amount of fat in the liver and abdomen (especially visceral fat, or fat surrounding the internal organs) than the polyunsaturated group.

Furthermore, the total amount of body fat was greater in the saturated fat group, while the increase in muscle mass was three times less compared with those who ate polyunsaturated fat. Thus, gaining weight on excess calories from saturated fat caused more body fat and less muscle mass than overeating a similar amount of polyunsaturated fat.

The director of the study notes that these findings can be very useful in curbing disease.

"Liver fat and visceral fat seems to contribute to a number of disturbances in metabolism. These findings can therefore be important for individuals with metabolic diseases such as diabetes," Ulf Risérus, associate professor at the Department of Public Health and Caring Science and director of the study, said in a press release.

"If the results regarding increased muscle mass following consumption of polyunsaturated fat can be confirmed in our coming studies, it will potentially be interesting for many elderly people, for whom maintaining muscle mass is of great importance in preventing morbidity."