"Will switching from butter to olive oil help me lose weight?"
Dietitians are frequently asked which foods promote weight loss. Although individual foods don’t really “boost metabolism” – at least not to a meaningful extent – there are certainly some exchanges that can help promote weight loss for those who desire it. Instead of a full plate of pasta, replace half the plate with steamed vegetables. Instead of drinking soda or alcohol, drink water. Over time, these changes add up.
On this topic, I’ve heard many people enthusiastically report that they’ve replaced butter with olive oil in all of their recipes, anticipating that this will result in weight loss. Unfortunately, that’s unlikely to be true.
What’s important to understand is that the biggest factor in weight changes is your balance of calories consumed versus burned on a daily basis. And olive oil and butter are virtually identical calorie-wise. They each contain about 100-120 calories per tablespoon, meaning they’re both very dense calorically. As the old saying goes, “six in one, half-dozen in the other."
Now, can a case be made that olive oil is healthier than butter in some ways? Sure. The American Heart Association consistently lists olive oil among other foods that are rich in unsaturated fatty acids and therefore beneficial for heart health when they replace foods high in saturated fats, like butter. The majority of health experts seem to agree with this, although there remains a great deal of debate and disagreement regarding the link between saturated fat consumption and heart disease. My point, however, is that this is an entirely separate argument – dietary approaches recommended for heart health and weight loss are not always the same.
The confusion here comes from the belief that a “healthy” food, with a high-quality profile of nutrients, is automatically better for weight loss as well. This is often true – most people would agree that broccoli is a more nutritious food than cake, and if you replace the cake in your diet with broccoli it will probably also help with weight loss. That’s because broccoli is both less dense in calories and more physically filling thanks to its high fiber content.
Those factors don’t necessarily hold true with olive oil and butter. While it may, in some ways, be useful to substitute olive oil for butter, don’t assume it will help you lose weight. If you’re making changes to your diet, think critically about what your goals are and if the changes you’re making are actually useful to achieve them.