To gain muscle and lose weight you need to use the right energy system

There's a lot of talk around weight loss – how to achieve, what method works for what body type, blood type, or even your star sign. 

But really being able to hit the sweet spot that burns those calories comes down to accessing the right energy system at the right time.

Man machine

The human body is an efficient energy consuming and burning machine. 

It breaks down the food we eat into three types of macronutrients: carbohydrates, proteins and fats. Your body then stores this energy and uses it for absolutely everything we do; from pumping blood around the body to lifting weights. 

Without enough energy from food, the body begins to break down and we literally die! With these consumed macronutrients, your body utilises three different pathways of energy expenditure for varying rates and intensities of physical exercise. 

These are:

The ATP – CP System  

This is our explosive, powerful, very short-term energy system that's recruited from two chemical compounds stored in our body: ATP (Adenosine Triphosphate) and CP (Creatine Phosphate). 

This stored energy is quickly used up in exercises such as maximal sprints, jumping and powerlifting. It only lasts between five-eight seconds and thus anaerobic in nature (without oxygen). Spending time training this energy system is vital for certain sports and professions (sprinters, for example). This is the energy system that helps with throwing serious weights around the gym and really finding out just what your body is capable of. 

The Glycolytic System 

Five seconds into your heavy lifting set the ATP-CP energy stores are depleted and the body seamlessly moves into using stored glucose (carbohydrates) for fuel (to create ATP again). Think of this system as still being anaerobic but defined by the nasty burning feeling you get in your muscles as you push through the last reps of your leg press set. Breaking down this glucose (glycogen) results in muscle fatigue and a nasty by-product called lactic acid.


If you want to build muscle, then this is your goal zone.

The Oxidative System 

Around four minutes into your sustained exercise, your body will transition from the glycolytic system into the oxidative or aerobic system. This energy system is powered by the oxygen we consume during long bouts of exercise.

It delivers rich, oxygenated and nutrient-filled blood to our muscles and results in increased endurance. This system utilises carbohydrates, proteins and fats to resynthesise ATP again. 

Now get to the fat loss

Training anaerobically is vital for building muscle. The more muscle you have, the greater your resting metabolic rate. This means that you can literally eat more food without doing anything at all – a serious bonus! 

But if your body is lousy at utilising oxygen for burning through all the energy we have consumed, then that means you will have to constantly be in the gym slaving away – not very practical, right?

Most activities we do outside of the gym involve the aerobic system, so the more efficient we make this system, the quicker our bodies can utilise the food we eat for fuelling us. 

This system burns the most calories as fuel, but if the intensity isn't high enough your body will find ways to conserve as much energy as possible to keep you going. 

Now obviously this is bad for fat loss, as we want to burn as many calories as possible so that our body starts to use up stored fat for fuel. 

Small step to giant leap

When it comes to burning stubborn fat that won't budge, the human body can really put up a fight. It knows full-well that your diet on the weekends is poor, you don't eat enough healthy whole foods, and you often skip meals. 

At the end of the day, your body is looking out for you and trying to do its best job at keeping you alive. When it comes to choosing the right energy system to base your training around; the answer is to become as efficient as possible at burning ALL the energy you consume. 

Science shows that HIIT is paramount for burning fat, and hypertrophy and strength is just as important for increasing resting metabolic rate. 

The energy method

Do heavy lifting, build muscle so that your resting metabolic rate increases and do short, sharp bouts of very high-intensity exercise (HIIT) so that your body is forced to use as many calories as possible.  

There is another bonus to high intensity work, called EPOC (Excess Post-exercise Oxygen Consumption); in a nut-shell, when you have finished your heavy lifting session, balls-to-the-wall circuit or sprint intervals session, your body consumes far more oxygen than usual for many hours afterwards and this results in more calories being burned for no effort at all – basically your golden ticket to Shredsville.

You're only ever going to see results if you train hard (therefore elevate EPOC) and become efficient at multiple modes of training.