A recent study published in Cell Reports suggests that consuming a diet high in oleic acid, a monounsaturated fatty acid prevalent in olive oil, might exacerbate obesity more than other dietary fats.

The research indicates that oleic acid promotes the creation of new fat cells in the body. Elevated levels of oleic acid enhance the activity of the AKT2 signaling protein while diminishing the LXR regulatory protein, leading to accelerated growth of precursor cells that develop into fat cells.

According to Michael Rudolph, Ph.D., assistant professor at the university of Oklahoma College of Medicine, “We certainly know that the types of fat that people eat have changed during the obesity epidemic. We wanted to know whether simply overeating a diet rich in fat causes obesity, or whether the composition of these fatty acids that make up the oils in the diet is important. Do specific fat molecules trigger responses in the cells?”

Rudolph and his research team, including Matthew Rodeheffer, Ph.D., from Yale University School of Medicine, conducted experiments where mice were fed specialized diets rich in specific fatty acids found in coconut oil, peanut oil, milk, lard, and soybean oil. The study revealed that oleic acid was uniquely effective in stimulating the proliferation of fat cell precursors compared to other fatty acids.

“You can think of the fat cells as an army,” Rudolph said. “When you give oleic acid, it initially increases the number of ‘fat cell soldiers’ in the army, which creates a larger capacity to store excess dietary nutrients. Over time, if the excess nutrients overtake the number of fat cells, obesity can occur, which can then lead to cardiovascular disease or diabetes if not controlled.”

Dietary Fat Complexity

Isolating specific fatty acids in a typical human diet is challenging, as people usually consume a mix of fats from various sources. Though, Rudolph noted that oleic acid levels are increasing in the food supply, especially with limited access to diverse food options and the prevalence of fast food.

“You can think of the fat cells as an army…it initially increases the number of ‘fat cell soldiers’ in the army.”

Rudolph advises, “I think the take-home message is moderation and to consume fats from a variety of different sources. Relatively balanced levels of oleic acid seem to be beneficial, but higher and prolonged levels may be detrimental. If someone is at risk for heart disease, high levels of oleic acid may not be an excellent idea.”