Fats are a type of nutrient that you get from your diet. It is essential to eat some fats, though it is also harmful to eat too many.
The fats you eat give your body energy that it needs to work properly. During exercise, your body uses calories from carbohydrates you have eaten. But after 20 minutes, exercise then depends on calories from fat to keep you going.
You also need fat to keep your skin and hair healthy. Fat also helps you absorb vitamins A, D, E, and K, the so-called fat-soluble vitamins. Fat also fills your fat cells and insulates your body to help keep you warm.
The fats your body gets from your food gives your body essential fatty acids called linoleic and linolenic acid. They are called "essential" because your body cannot make them itself, or work without them. Your body needs them for brain development, controlling inflammation, and blood clotting.
Fat has 9 calories per gram, more than 2 times the number of calories in carbohydrates and protein, which each have 4 calories per gram.
All fats are made up of saturated and unsaturated fatty acids. Fats are called saturated or unsaturated depending on how much of each type of fatty acid they contain.