EPOC and Afterburn – Are They Real or Is It HYPE?

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Today I thought I would post a guest blog from my good Friend Mike Roussell. Mike is an nutrition expert and author of the nutrition chapters in both Men’s Health Power Training AND my upcoming book Cardio Strength Training. The topic of EPOC is one of the main focuses of my upcoming book (due out January 2010) and I think this blog post sums things up nicely!

I talk a lot about EPOC, Afterburn, and the idea of burning calories and fat even after your workout is over. Over the past couple blog posts there have been some questions from readers about this concept. Is is real? Is it over hyped? How many calories are we talking about? Here is a question/comment from a reader, Jack , about this very thing……


 

Jack: “You wrote that “Metabolic Circuits are essential to really crank up your weight loss because they have been shown in research studies to increase the total number of calories that you burn over the 38 hours following your workout.” Is this the same as when people speak of EPOC or a separate phenomenon?”

“I ask this because I have read that EPOC is about 8-15 percent or so (depending upon activity intensity) of the total kcal expenditure during the chosen activity. As such quite a number of writers claim that any metabolic boost is not nearly as significant as it is made out to be. Not being engrossed in all of the research leaves me slightly confused as to which is closer to the reality of the situation.”

 

“Just curious if you can add some more clarity. I do not mean to come across as argumentative, I am just somewhat confused by what seems to be a back and forth between claims about significant metabolic boosts for 1+ days after certain types of activity and other claims that such impacts are largely overblown.”

 

This is a great question. Yes, I was talking about EPOC or what Alwyn Cosgrove calls Afterburn.

 

What is EPOC/Afterburn? It is basically a phenomenon that occurs when you lift weights or do the metabolic type of training that I have been talking about the past couple of blog posts. The tabata protocol is a perfect example of something that elicits an afterburn effect. A very simple way of thinking about EPOC is that when you do this type of training you exert yourself beyond what your body is capable of handling (i.e. your body can’t keep up); it then uses the next 12, 24, or even 36 hours to ‘catch up’ metabolically. ‘Catch up’ = burning calories.

 

How many calories do you burn with EPOC? A bunch.

 

What is the reality of the situation? Is is 8%? 15% as Jack noted about?

 

I was emailing back and forth with Alwyn Cosgrove about this and here is what he had to say…

 

The “reality of the situation” is not going to be found in textbooks or papers unfortunately.

 

Basically it’s hard to truly measure caloric expenditure (during and post workout) of anaerobic activity and recovery when you are using a measure of aerobic work (traditionally oxygen debt).

Studies comparing the same volume of caloric work (ie same calories burned) from interval training or weight training to aerobic training, show a massive difference in total fat lost over a period of time?

 

Why? EPOC? Some other type of post workout change?

 

I don’t think we know the exact mechanism yet – we just know that SOMETHING happens post workout as a result of high intensity metabolic work that doesn’t happen with lower intensity work, even if calories burned during training are equal.

 

The numbers shown with EPOC don’t explain it completely. It would be nice to know exactly what happens, but more importantly we KNOW what happens — more fat loss.

 

Bottom Line – don’t be confused by “a back and forth between claims” – just do what has been shown over and over again to work.

 

Aside from all of this: – all the studies on EPOC are performed on aerobic work or standard weight training.

 

■ The few studies on circuit based weight training show a higher effect.

■ There has never been a formal study on the type of training we use. However – at 250 clients training 3 times a week for the past several years – I think I have more than enough “data”

■ There aren’t any studies on an accumulative effect on EPOC (they all look at single workouts). If it’s even a 10% increase for 24 hours, is there an accumulative effect if you train every 24 hours? (there are studies showing an increased EPOC with two shorter daily sessions as opposed to one of the same total length) — the question is how long will the “between sessions” last?

We know that weight training increases resting energy expenditure and there is an EPOC effect. All we do is attempt to continuously ramp that effect up.

 

Again – in truth we don’t know the mechanisms behind this completely — I just know what results my clients get.

The research doesn’t disprove the results. It just looks at the mechanisms to explain the results.

 

(Mike again…) We talk a lot about EPOC in Warp Speed Fat Loss. As Alwyn said is all the extra calorie burning from EPOC? Not sure? Does is matter if we know exactly what it is from? Not entirely, as if you go on Warp Speed Fat Loss and lose 4 pounds a week for 4 weeks would you really care if it was EPOC or not? You’d just be happy you lost the weight right? So for now the jury is out but as soon as we learn more I’ll let you know. For the time being let’s just do what we know works —> This works

 

This article was written by Mike Roussell. Mike Roussell is a nationally renowned nutritionist and the president of the Naked Nutrition Network. He is currently a doctoral candidate in nutrition at Pennsylvania State University.

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