Conjugated linoleic acid (CLA) is a mixture of different isomers, or chemical forms, of linoleic acid. Linoleic acid is an essential fatty acid—a type of fat that your body needs for optimum health.

Based on preliminary evidence, CLA has been promoted as a "fat-burning" supplement and as a treatment for diabetes. However, there is little evidence that it works and growing evidence that CLA might actually worsen blood sugar control in people who are overweight.

Although linoleic acid itself is an important nutritional source of essential fatty acids, there is no evidence that you need to get conjugated linoleic acid in your diet. CLA does occur in food, but it would be very difficult to get the recommended dose that way. Supplements are the only practical source.