Fact or Fable?

Many people who want to lose weight often perform long cardiovascular workouts at a low intensity. Many cardio machines also provide guidelines wherein exercise on lower intensities is often named weight loss or fat burning zone. (Usually around 60-70% of Maximum Heart Rate). But is it the most effective training intensity for weight loss?

It is true that prolonged exercise at this intensity allows the muscles to burn fat to generate energy. It only seems logical that trainers and producers of fitness machines claim this is the best intensity for burning fat and losing weight. However, although the muscles can burn fat more easily at lower intensities than at higher intensities, the body does not use a lot of energy at low intensity in the first place. As a result, weight loss by training at low intensities is rather underwhelming.

Of course it is possible to lose weight at lower intensities, but it is quicker and more effective to train at higher intensitities. Although it is true that the muscles start using carbohydrates as primary fuel during training, the resting metabolic rate after training remains elevated for a longer period (EPOC), during which more fat is burned. Depending on the intensity and duration of the workout, this effect can persist for up to several days. This effectively raises the energy cost and fat burning capacity well beyond the effects of a low intensity work out. Moreover, it has several beneficial side effects, such as increased endurance or maximal oxygen consumption and increased fat burning capacity. These adaptations to training make it increasingly easier to burn fat and lose weight.

In conclusion, low intensity exercise is not as effective to burn fat as claimed. It is far more effective and time efficient to train at higher intensities if you want to lose weight.