Fat has 9 calories per gram, more than 2 times the number of calories in carbohydrates and protein, which each has 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.
Examples of fats include butter, cream, vegetable shortening, and lard. Examples of pure compounds that are fats include triglycerides, phospholipids, and cholesterol.
There are two types of fat that should be eaten sparingly: saturated and trans fatty acids. Both can raise cholesterol levels, clog arteries, and increase the risk of heart disease.