What's Your EPOC

In order to lose body fat, you must burn off more calories than you consume. Despite the proliferation of diets- low carbohydrate, low fat, high protein, high carbohydrate etc this simple rule remains. I don’t want to talk about nutrition here as this is more than adequately covered in another chapter in this book, but suffice to say the caloric balance is still important.

I’ve lost count of how many times I’ve heard people say “I barely eat anything – I eat like a bird and I still gain weight”. Oh really. You are eating fewer calories than you need and your body is gaining weight? Impossible. This violates the law of thermodynamics. Usually it’s a case of not really being aware of how much you are actually eating. Because let’s face it – if your body was capable of producing body weight from nothing, then we better get you sent over to NASA or UNICEF immediately – with magical genes like yours, we might just be able to solve the Third World’s hunger problem.

Fat loss is all about caloric expenditure. We must burn more calories than we take in, and the real key to doing this, as mentioned before, is not aerobic training, which will burn calories while you are doing it, its anaerobic training, which burns calories while you are doing it AND increases the calories burned for hours afterwards. In the case of weight training, if we build muscle and keep it, that burns calories forever more. Even when you sleep!



The key with anaerobic training is what is known as EPOC. Anaerobic exercise burns a ton of calories while you are performing it. However, the metabolism remains elevated following this type exercise. This was, at one time, referred to as the oxygen debt, but is now referred to as the excess post-exercise oxygen consumption (EPOC). The recovery of the metabolic rate back to pre-exercise levels can require several minutes for light exercise (aerobic training), several hours for very heavy exercise (anaerobic cardio training), and up to 12 to 24 hours or even longer for prolonged, exhaustive exercise (interval training or circuit weight training).



The EPOC can add up to a substantial energy expenditure when totaled over the entire period of recovery. If the oxygen consumption following exercise remains elevated by an average of only 50 ml/min or 0.05 liter/min, this will amount to approximately 0.25 kcal/min or 15 kcal/hr. If the metabolism remains elevated for five hours, this would amount to an additional expenditure of 75 kcal that would not normally be included in the calculated total energy expenditure for that particular activity. This major source of energy expenditure, which occurs during recovery, but is directly the result of the exercise bout, is frequently ignored in most calculations of the energy cost of various activities. If the individual in this example exercised five days per week, he or she would have expended 375 kcal, or lost the equivalent of approximately 0.1 pounds of fat in one week, or 1.0 pounds in 10 weeks, just from the additional caloric expenditure during the recovery period alone. This is the key to maximizing the return on your exercise investment.

The next obvious idea is – if you trained the next day while your metabolism is still elevated, will we have an even higher return – is the effect accumulative? Is the whole greater than the sum of the parts?

Science has yet to give us an answer, however in the real world, I think so. I have seen amazing results with my clients using this exact protocol.

Interval training

So is there a better way of performing cardio workouts to prevent these adaptations, and rapidly improve fat loss results? Yes. The key is to perform what is known as interval training or Boot Camp.



Interval training simply refers to a series of intense activity separated with short rest periods. Through using interval training you are able to exercise at a higher intensity without getting tired. In other words – because we alternate the periods of high intensity work, with periods of lower intensity work – you are able to do much more work in the same time period than you were before.



The beauty of this is as you improve, the work intervals can get harder and harder, and the recovery intervals can be shortened, or performed at a higher speed. In fact, there is no end in site, and no downside to interval training (other than it is really hard).