Why Long, Slow Cardio Is Not The Best Way To Lose Body Fat

There is an extremely widespread misconception that the best way to burn fat is to perform long bouts of slow, tedious aerobic exercise.  Go into any gym and you will find countless overweight individuals plodding away on the cardio machines (treadmills, cross trainers, stationary bikes etc.).  If you return several months later, you will find the same individuals doing the same type of exercise with no real results to show for it.


Many of these pieces of equipment will even have a little chart on them showing you the “fat burning zone”, an area towards the lower end of the intensity scale.  The idea is that exercising at a low intensity for a long period of time is the most effective way to lose fat.  This is actually a misconception stemming from peer-reviewed sports science research.  The research shows that we burn the highest proportion of fat for energy at low intensities.  What this ignores is the total amount of energy required by the exercise and the amount of energy we burn once the exercise has finished.


A smaller percentage of something big can be greater than a larger percentage of something small!  Therefore generally speaking, the harder you train the more fat you will burn.  If we also take into account the additional energy we burn after the exercise, referred to as EPOC (excess post-exercise oxygen consumption) in the scientific literature, we can see that we burn more energy after high intensity exercise as well as during it.


Looking now at different modes of exercise, it is actually becoming more widely accepted that resistance training (repetitive exercises using weights, resistance machines, bands or bodyweight) is more effective for improving body composition than cardio.  The research shows that “EPOC” is higher after resistance training than after cardio (in fact, some studies have shown energy expenditure at rest to be elevated for several days after resistance training!).  Additionally, any gains in lean muscle mass as a result of the resistance training will serve to further elevate resting metabolic rate and improve markers of health such as insulin sensitivity and bone mineral density.  Resistance training also has a more favourable effect on our hormonal profiles.  Our bodies release Growth Hormone (a hormone which maximises fat breakdown) in greater quantities following this style of training, whereas long bouts of cardio leads to elevations in the stress hormone Cortisol.  Over time, a chronic elevation in Cortisol leads to fat storage (especially visceral fat, around the belly) and inflammation.


Losing weight is not an easy process for most of us.  It is therefore extremely important to utilise the most efficient training protocols possible.  This means ditch the jogging and aerobics and start training with weights or performing sprint intervals.