Conjugated linoleic acid (CLA) is a type of linoleic acid which belongs to Omega-6 fatty acids. It is contained in body fluids and the fat tissue, but the human organism cannot synthesize it alone. The main sources of CLA for the human organism are meat and dairy products. It is needed for maintenance of the optimal functions of the phospholipid membranes of the cells. It increases the ability of the cell membrane to let in important for the organism substances, which are responsible for the normal function of the metabolic processes in the cells. Highly restrictive nutrition plans, low in fats, can lead to deficiency of CLA in the organism and this can slow down the metabolism and hinder the achievement of the desired goal. The higher concentration of CLA in the organism stimulates disintegration of fat cells in a calorie deficit in weight loss programs and benefits muscle growth in muscle building programs.