Fatty Acid in Olive Oil Drives Obesity? Not Exactly

This headline from the University of Oklahoma captured our attention: “Fatty acid in olive oil drives obesity.” It was even more attractive when we read and understood this was not more of the linoleic acid and seed oils dogma bubbling up. It was a headline prompted by a new study of oleic acid and molecular signaling it stimulates to prompt the formation of fat cells. The study appeared in Cell Reports, a respectable peer-reviewed journal.

It was actually a good study, showing in mice that oleic acid can prompt the formation of fat cells – adipogenesis – through molecular signals called the AKT2 pathway. So far, so good.

But the leap to saying that oleic acid in olive oil drives obesity is a big one. This is, after all, a mouse study. It is all about a particular molecular pathway, not the effect of olive oil fatty acids on whole, free-living human beings. As the researchers point out in their manuscript, “dietary fat sources are a complex mixture of fatty acids.” So isolating the effects of one single fatty acid is not so easy, especially in humans.

Oleic Acid May Actually Help Weight Regulation

If we look to the scientific literature, we find that the evidence from human intervention studies supports a very different conclusion than the dubious Oklahoma headline.

“Current findings lend support to advice not restricting consumption of oleic-acid-rich meals so as to maintain a healthy body weight.” This conclusion comes from a systematic review of clinical studies in humans that tested the effects of diets enriched with oleic acid on body weight for preventing obesity.

If anything, clinical studies show that oleic acid might be helpful for reducing or preventing excess adiposity. Not that it is exceptionally effective, but it certainly strains our credulity to say that it is driving more obesity.

So the molecular signaling study of oleic acid in mice is certainly worthwhile. But projecting that it implicates olive oil as a cause of rising obesity is an overreach.

Click here for the new study in Cell Reports and here for the systematic review from Advances in Nutrition. For the University of Oklahoma press release, click here.

Grove of Olive Trees in Bordighera, painting by Claude Monet / WikiArt

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June 8, 2025