There are several methods to eliminate unnecessary subcutaneous adipose tissue. Aerobic exercise seems to be the cheapest and most efficient method compared to diets, pills or even surgery. Subcutaneous adipose tissue can only be reduced by lipolysis and oxidation in the working muscles. The intensity of exercise is the most relevant factor in fat oxidation. Even though fat oxidation is highest at low to moderate intensities, well trained athletes have their highest fat oxidation at the ventilatory threshold. Therefore, different intensities for trained compared to untrained persons have to be recommended in order to burn fat. The determination of concentrations of lactate seems to be of important practical use.