What Is the Difference Between Fat, Oils, and Triglycerides?

Fats and oils are terms commonly used to refer to food sources of triglycerides. Often fat and oil are considered to be different based on appearance: fat is solid at room temperature and oil is liquid. However, they are really two of the same thing, generally speaking. They are both collections of triglycerides. For simplicity, we will use “fat” to include all sources of triglycerides.

A triglyceride molecule is a combination of three fatty acids linked to a glycerol molecule backbone (Figure 5.1). Although a triglyceride molecule will always have this general design, there can be great variability in the type and combinations of fatty acids that link to glycerol. Only one glycerol molecule exists, but like monosaccharides there are numerous different types of fatty acids in nature. Furthermore, if a triglyceride involves three fatty acids then monoglycerides and diglycerides will have one and two fatty acids attached to glycerol, respectively. Technically, they can be considered fat as well.