If long, slow, steady-state aerobics was the key to fat loss every
person who crosses the finish line of a marathon or Ironman would have
very low body fat. This just isn't the case. Numerous people who train
for an endurance event gain weight.
It is a myth that aerobic exercise is the only way to burn fat because there are also other exercise types that burn fat. Strength training for example, which is a type of exercise that requires muscles contraction against resistance is a very efficient way for using fat. The greater the energy requirements of an exercise the larger number of burned calories.