Good oil has its limits too: Why olive oil may be expanding your waistline, one fat cell at a time

Synopsis
Despite its reputation as a heart-healthy superfood, olive oil may have a hidden downside. Scientists found that oleic acid can activate proteins that promote the multiplication of fat cells. While not a call to abandon olive oil entirely, the study urges moderation, especially for those consuming large amounts through processed foods rich in the same fat.
Meet the ‘Fat Cell Soldiers’ That Olive Oil Might Be Recruiting
In a controlled study using mice, Rudolph and his team fed diets high in various fats — from coconut oil to soybean oil — to see how they impacted the body. But only one fat stood out: oleic acid. This compound, abundant in olive oil and processed foods, triggered an increase in the body’s “fat cell soldiers,” or precursor fat cells.According to Rudolph, oleic acid stimulates a protein called AKT2 while suppressing another called LXR, both of which regulate fat storage. The result? More fat cells ready to store dietary nutrients — and a greater capacity for weight gain. “If the excess nutrients overtake the number of fat cells, obesity can occur,” Rudolph warned. “That can then lead to cardiovascular disease or diabetes if not controlled.”
Don't Ditch Your Olive Oil Bottle Just Yet
Before you throw your olive oil out with the bathwater, there's a crucial caveat. The researchers stress that real-world diets are more complex — no one eats isolated fats in a lab setting. Plus, olive oil still boasts numerous health benefits: it’s rich in antioxidants, supports brain function, improves heart health, and has even been linked to reduced cancer and dementia risk.The problem isn’t olive oil itself — it’s the quantity and context in which it’s consumed. Diets dominated by ultra-processed foods rich in oleic acid could tilt the balance. “Moderation is key,” Rudolph said. “Relatively balanced levels of oleic acid seem to be beneficial, but higher and prolonged levels may be detrimental.”
Olive Oil is Still the Good Guy — Just Not the Only Guy
In a world obsessed with ‘superfoods,’ this study is a wake-up call that even healthy ingredients have their limits. Olive oil remains a nutritional powerhouse — but when consumed in excess or combined with unhealthy food habits, it might be helping your fat cells multiply behind the scenes.So, yes — drizzle that olive oil over your salad. Just don’t drown in it.