The oils you use in the kitchen might seem like a small part of your diet, but they can have a surprising impact on your health. While oils are a form of fat—and fat is often viewed with suspicion—not all fats are created equal. In fact, your body actually needs some fat to function properly.

Fats provide energy, help the body absorb certain vitamins, regulate hormones, and support the growth of cells. Some types even help protect your heart. The key is choosing the right kinds of fat—and by extension, the right cooking oils. The goal isn’t to avoid fat entirely, but to be smart about which ones end up in your meals.

Let’s break down which oils support your health—and which are better left out of your diet.