Olive oil is healthier than butter for most purposes, particularly when it comes to heart health. The difference comes down to fat composition: olive oil is 68% monounsaturated fat and only 19% saturated fat, while butter flips that ratio almost exactly, at 66% saturated fat and just 26% monounsaturated fat. That single distinction drives most of the downstream health effects.
How Their Fat Profiles Compare
Fat is the main event in both olive oil and butter, and both contain roughly the same number of calories per tablespoon (around 120). But the type of fat they deliver is fundamentally different.
Butter gets two-thirds of its fat from saturated fatty acids, the kind that raises LDL (“bad”) cholesterol in your blood. It contains only about 3% polyunsaturated fat, the type your body can’t make on its own and needs from food. Olive oil, by contrast, is dominated by monounsaturated fat (68%), with 13.5% polyunsaturated fat and less than a fifth from saturated sources. The American Heart Association recommends keeping saturated fat below 6% of your daily calories, which works out to roughly 13 grams on a 2,000-calorie diet. A single tablespoon of butter uses up more than half that budget. A tablespoon of olive oil uses about a quarter.
Effects on Cholesterol
Clinical trials that swap butter for olive oil in people’s diets consistently show the same pattern. A controlled study published in The American Journal of Clinical Nutrition found that moderate butter intake raised both total cholesterol and LDL cholesterol significantly compared to olive oil. Butter did also raise HDL (“good”) cholesterol compared to participants’ usual diets, but that bump doesn’t offset the LDL increase. Elevated LDL is one of the strongest predictors of atherosclerosis, the buildup of plaque in arteries that leads to heart attacks and strokes.
Olive oil either holds LDL steady or nudges it downward, depending on what it’s replacing in your diet. If you’re swapping out refined carbohydrates for olive oil, you may see improvements in both LDL and HDL. If you’re replacing butter with olive oil, the main benefit is avoiding the LDL spike that butter would have caused.
Cardiovascular Protection
The largest and most influential trial on olive oil and heart disease is PREDIMED, a Spanish study that followed thousands of people at high cardiovascular risk. Participants assigned to a Mediterranean diet supplemented with extra virgin olive oil had significantly fewer strokes, heart attacks, and cardiovascular deaths compared to those following a low-fat diet. The olive oil group also saw a 38% reduction in the relative risk of atrial fibrillation, a common heart rhythm disorder that raises stroke risk.
No comparable large-scale trial has found similar protective effects from butter. Some research has pushed back against the idea that butter is actively dangerous in moderate amounts, but the evidence consistently favors olive oil as the better choice for long-term cardiovascular health.
Blood Sugar and Metabolism
Olive oil appears to have a real advantage for blood sugar control. Research on people with type 1 diabetes found that adding extra virgin olive oil to a high-glycemic meal (one that would normally spike blood sugar) blunted the post-meal glucose surge compared to adding butter. The mechanism seems to involve slowed gastric emptying: olive oil delays how quickly food leaves the stomach, which means carbohydrates are absorbed more gradually.
More broadly, saturated fats like those in butter impair endothelial function, the ability of blood vessels to relax and expand properly. This matters because stiff, poorly functioning blood vessels contribute to high blood pressure and insulin resistance over time. Monounsaturated and polyunsaturated fats, the kinds dominant in olive oil, improve post-meal metabolic control in both healthy people and those with type 2 diabetes.
Polyphenols: What Butter Doesn’t Have
Extra virgin olive oil contains a class of compounds called polyphenols that butter simply lacks. The most studied of these is oleocanthal, the compound responsible for the peppery, throat-catching sensation you get from high-quality olive oil. Oleocanthal works as both an antioxidant and an anti-inflammatory, and one study found that olive oil with high oleocanthal concentrations significantly decreased several inflammatory markers in people with metabolic syndrome and fatty liver disease.
The European Food Safety Authority has approved a specific health claim for olive oils containing at least 5 mg of polyphenols per 20 grams of oil, stating that these compounds help protect blood fats from oxidative damage. This is a benefit unique to extra virgin olive oil. Refined olive oil, which has been processed to remove flavor and color, loses most of these polyphenols. Butter contains fat-soluble vitamins A, D, E, and K2, and some butyrate (a short-chain fatty acid that may benefit gut health), but these don’t match the breadth of olive oil’s bioactive compounds.
Where Butter Still Works
Butter isn’t nutritionally empty. It provides vitamin A and small amounts of vitamin K2, a nutrient that’s harder to find in most Western diets and plays a role in calcium metabolism. Grass-fed butter contains higher levels of these nutrients along with more conjugated linoleic acid, a fat with some evidence of anti-inflammatory effects, though the amounts are small.
From a cooking standpoint, butter has a lower smoke point than most olive oils, which limits its use for high-heat cooking but makes it well-suited for baking and finishing dishes. Extra virgin olive oil performs well for sautéing and roasting at moderate temperatures, and its polyphenols remain largely intact under normal cooking conditions. For deep frying or very high heat, refined olive oil or avocado oil are better options than either butter or extra virgin olive oil.
The Practical Swap
You don’t need to eliminate butter entirely to see health benefits. The research consistently points to replacement as the key strategy: using olive oil where you would have used butter shifts your fat intake from saturated toward monounsaturated, lowers LDL cholesterol, and adds anti-inflammatory polyphenols. Drizzle olive oil on bread instead of spreading butter. Use it as your default cooking fat. Save butter for the occasional recipe where its flavor genuinely matters.
If you’re buying olive oil for health, go with extra virgin. It’s the least processed form and contains the highest concentration of polyphenols. Look for a harvest date on the bottle, as polyphenol content degrades over time. Dark glass or tin packaging protects against light damage. Store it in a cool, dark place and use it within a few months of opening.