Fat is perpetually villainized, but it shouldn’t be. You need fat to function. But the question is: which are the healthy fats and which aren’t?

“For years, fat was seen as unhealthy so we began a strong focus to remove it from our diets whenever we could,” says Toral Shah, a nutritional scientist at the UK-based Wiley’s Finest supplements. “But, over the past decade, the perception of dietary fat has changed considerably, emphasizing the importance of fat type over total quantity.”

Saturated fats, often found in deep-fried foods, should generally be consumed only occasionally. But unsaturated fats, like avocados and fish oils are now considered beneficial. In fact, Shah says good fats may even help lower the risk of heart disease.

With fat now considered firmly on the menu, here’s everything you need to know about which foods to prioritize.

What does fat do in our bodies?

Fats aren’t just a source of energy. According to Dr. Krutika Nanavati, a registered clinical nutritionist and sports dietitian, fats serve a number of critical roles including helping with the absorption of fat-soluble vitamins A, D, E, and K, which are vital for various bodily functions.

“Fats are also integral components of cell membranes and are involved in the production of hormones that regulate metabolism and other bodily processes,” Nanavati says. “Fats also act as a cushion for vital organs and provide insulation to maintain body temperature.”

Shah adds that good fats also help signal activity between cells, facilitating protein and biochemical cascades that help regulate growth, immunological responses, and reproductive processes.

How else does fat protect us?

According to Shah, upping your healthy fat levels can also protect your:

Heart health
“Omega-3s reduce blood pressure and may increase HDL cholesterol, protecting your heart and reducing the risk of sudden, fatal heart attacks by up to 45%.”

Brain and mental health
“Regular omega-3 intake reduces the risk of depression and anxiety, and may protect against cognitive decline.”

Cancer risk
“Omega-3s decrease inflammatory molecules, reducing chronic inflammation linked to heart disease, cancer, and other illnesses.”

When can fat give us an edge?

The ketogenic diet, in which athletes ditch carbs to encourage the body to rely on fat stores is an obvious example of when focusing on fat may give us an athletic edge. “Some athletes and bodybuilders use ketogenic or higher-fat diets to manipulate energy metabolism, but long-term benefits for performance are still debated,” says Shah.