Interval Training = ‘Afterburn’ = Fat Loss. Or Does It?

Excess Post-exercise Oxygen consumption or EPOC. A lot has been written about it recently. Some of the best rapid fat burning courses attribute their successes to it (see my previous post: The ‘Big Three’ Fatloss eBooks – Which Is Best?). But is that really the case? Something doesn’t quite add up. Before I discuss that point, lets look the EPOC theory a bit closer first:

EPOC – burn calories for hours after you exercise?

What is EPOC? Well, its just a fancy way of saying that more oxygen than usual is used by your body after a bout of exercise. The theory is that this extra oxygen is used to replenish, repair and adapt the body to the stress (workout) that it has just encountered. Since these all require energy, the excitement around EPOC is that it is a sign that you’re burning calories (fat?) while you’re resting. An afterburn effect. (Whoohoo!)

Or so it seems…

Anaerobic exercise produces a higher EPOC

Studies show clearly that anaerobic exercise (resistance training, interval training, complexes, etc) increases EPOC more than aerobic exercise (long, slow cardio – BLEGH!) does. Aerobic exercise burns more calories while you do it, but there is supposedly higher calorie burn during the EPOC that follows anaerobic exercise. Studies have also found that anaerobic exercise results more lost fat, even though much less calories are burnt during exercise. Most people, and many ‘experts’ just give EPOC the credit for that.

But is it really so?

Lets see…

OK, so oxygen usage can be elevated for a long time after exercise. It does taper off, but has been shown to still be elevated at the 36 hour mark! But how does that relate to calories burnt? Well, I have seen many people (myself included) lose 2kg or more of fat per week (not just weight – FAT) from weight training and ‘anaerobic cardio’, with almost no regular cardio. So lets add that up:

• 2 kg = 4.4 pounds
• 3500 calories in a pound of fat = 4.4 * 3500 = ±15,400 calories extra burnt in 1 week?!
• Lets say 1500 of those calories were burnt while working out that week (its much lower in reality)

So EPOC accounted for about 14000 calories over 7 days = ±2000 calories per day? HUH? 2000 calories actually burnt at rest? Sounds wrong to me.

Well, here’s the kicker.

None of the studies that found significant increases in EPOC when comparing anaerobic vs aerobic exercise reported an earth shattering calorie ‘afterburn’. In one study it was only 32 calories! Yes, 32! Where did the other almost 2000 calories per day from the missing fat go?

Well, it had to go somewhere. And I think I have an idea where.

Irritable muscle bullies fat cells?

I think that the old nutrient partitioning theory needs revisiting. You know, the one where the body rather feeds muscle, thereby starving fat cells. But I think its even more than that, I think that fat cells are forced to give up their lunch (stored fat) and their milk money too (‘normal’ daily nutrient allocation). There is definitely a very powerful hormone and neurotransmitter cocktail being produced in response to intense anaerobic training. While recovery is one of their targets, I think that forced confiscation of fat from fat cells is another.

I also don’t think that all the extra calories that the body is even being used/burnt. There is some wasting going on. And not purely in the form of heat, since that implies burning of calories.

In my opinion, EPOC is just a signal. A sign that something is happening ‘under the hood’. That a syndicate of very irritated muscle tissue is ‘bullying’ fat cells and wasting the calories that they rob from them, causing fat cells to shrink. I know, it sounds crazy, bt the EPOC theory has huge holes.

Do I have all (or any) the real answers? Dunno. All I know is that this can be exploited. And I have been for a while.

More next time..

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