Sunday, January 30, 2011

Fasted Cardio (Part 2): Intensity Theory In Question?

In Part 1 of this three part series, I set the stage for tackling a potential concern I knew I would be hearing about sooner or later, that is, the idea that fasted cardio somehow disproves or discredits the theory of absolute intensity and thus the theory of fat loss.

(Interestingly enough, a day after I posted that entry, a new article in favor of fasted cardio appeared on the T-Nation website... and also in favor of selling you a bunch of supplements.)

Anyway, like I said previously, this post is not designed to convince you whether fasted cardio works or doesn't work. I'm going to ignore that point entirely because you can read enough about that anywhere. You won't find what I'm about to say anywhere else on the Internet. No mindless rehashing of ideas in this post! Rather, we are going to assume that fasted cardio is effective and take it from there...

If you have done some reading about fasted cardio, you will see that it is most effective for people that do it as an adjunct to their normal training... that is... it has to be combined with other types of training.

Of course, that isn't to say that fasted cardio couldn't be effective on its own. I mean, if you are a sedentary individual who hasn't done anything in a long time, I'm 100% sure you will burn some fat doing it. Why? You increased your intensity from nothing to something.

Those two things being said... let's pretend all the claims about it are true. It works for fat loss. How does it match up to THE Theory of Fat Loss?

If you perform some sort of low intensity aerobic exercise for 60 minutes every morning before you eat, is that a good use of your time compared to performing 60 minutes of another type of activity (or even 60 minutes of cardio in a different state)? How many calories would that actually burn? How much fat loss would that result in after a month? Would you also be losing muscle mass because of the catabolic nature of fasted cardio and thus hindering long term fat loss progress? (There are also the people that take a little protein in the morning to combat those effects... which makes fasted cardio not fasted cardio... but more on that in part 3).

The best way to answer these questions is to look at it from two different perspectives... 1) The perspective of Joe "Mid-Life Crisis" Chill; and 2) An elite athlete or competitor.

The elite athlete or competitor is the easiest to discuss because he has very few limits. He is strong, coordinated, has excellent posture, and is motivated. He just needs to cut a few pounds of fat to be PERFECT for his season or competition. He has no daily time limits because he MAKES time for everything. Is fasted cardio going to work for him?

Well, if he stops all his training and replaces it with fasted cardio, then he ABSOLUTELY WOULD NOT!!! That would be ridiculous. I guarantee he would get fatter. Of course, he already knows this and wouldn't even think about doing that. He just wants to throw in a little fasted cardio in the mornings as a little "extra" thing to do. I bet it would work. That is because he would have a slight increase in his absolute intensity for the day or week or month, etc. Not only that, but he would perhaps get a bit more selective fat loss (the increased percentage of fat utilized as fuel during the fasted state) because of it.

Now, if he performed some other activity in the morning, something of higher intensity, for example, would it work even better? It might. It might not. This is where it gets complicated. Would the increase in high intensity activity effect his recovery and prevent him from training harder later? Perhaps. What if he just performed cardio at the same intensity after eating? As Cosgrove said in the article I linked to above... it wouldn't make much of a difference (although he said it much more harshly) even if you burned 30% more fat.

I don't know about you, but all this tells me is that fasted cardio should only be used as an adjunct to exercise... assuming that it works at all (which we are doing for the sake of argument), that is.

Now, let's take a look at our other example.

With Joe Chill, we have to discuss his fat loss limits. He is a sedentary individual who drank too much beer and put on too much weight since he graduated college 20 years ago. Now his wife isn't attracted to him anymore, and he needs to lose weight. Is fasted cardio his solution.

His limits that we are going to assume are:

Capacity Limits
1. Poor muscular strength and power
2. Poor muscular endurance
3. Poor cardiorespiratory capacity

Functional Limits
1. Coordination
2. Posture

1. One hour available to train 3x per week
2. Six months until his wife cheats on him

He has two options. He can spend his one hour a day performing fasted cardio or doing something else. Which limits does fasted cardio address? It only addresses muscular endurance (for his legs, and does a poor job of it) and cardiorespiratory capacity (also addressed poorly because fasted cardio is performed at a low intensity).

Also for the sake of argument, let's say Joe Chill actually performs a very thorough warmup every time he trains so that he doesn't get injured and fixes his postural problems (this isn't very likely, of course, but I want to set him up for success) AND trains consistently for the entire 6 months.

Would he be better off doing this or spending his time following the advice from The Theory of Fat Loss: A New Paradigm for Exercise? Following either protocol, he will lose fat. Now, I can't tell you which will be better in the short term for fat loss. In fact, fasted cardio might win over the course of only a month. But if you think that is what matters, then consider this...

With the fasted cardio, he improves his ability to perform fasted cardio. Following the new paradigm, he gets stronger, faster, more powerful, more coordinated, and more able to tolerate all sorts of activities at all sorts of levels of intensity... He also puts on more muscle mass (rather than potentially losing muscle mass).

With only an hour to train 3x per week, which one sounds better to you in the long term? Joe would be much better off ditching the fasted cardio in favor of following the principles covered in THE Theory of Fat Loss. I'm not saying that fasted cardio doesn't work. You do not need to have a ridiculously high capacity for intensity to burn fat. You just need it to burn fat OPTIMALLY. 

If you haven't done so already, check it out for yourself.

The Theory of Fat Loss: A New Paradigm for Exercise

So, I hope you agree with me now that fasted cardio probably isn't the best stand-alone option for fat loss... even if it does work as well as is claimed.

Of course, you still might say I'm missing the point entirely... fasted cardio works because you selectively burn fat as an energy substrate so you lose fat directly. The point of fat loss exercise, however, is not so much to burn a lot of fat during the training session (in fact, very very little fat is burned during high intensity exercise because glucose is the only substrate that can provide energy quickly enough); rather, the point of exercise is to increase your metabolism throughout the day so that while you are resting, you burn more fat. With that being said, my next post will give you my real opinion of fasted cardio and why it is an incredibly misguided practice...

Read Part 3 of this series: Fasted Cardio (Part 3): The LAZY Man's Dieting Gimmick


  1. Absolutely correct. Perhaps the lowest intensity activity that we perform, breathing, is done using mostly fat as a substrate. The extreme of this argument, then, goes back to square one: One could easily burn fat by simply not eating. The problem is that your body composition would be negatively affected in the long run, as these activities are largely catabolic. I don't think anyone can criticize a fat loss program for not discussing the fat-burning merits of breathing.
    But you put it another way, Tim. In order for the fasted cardio even to be able to work, you must already be in good shape and be able to perform a high amount of absolute intensity. Think about it! Otherwise, you would merely be an aerobic athlete, though only working at low intensities, and aerobic exercise just does not produce an athletic or athletic-looking body. I'd say that in no way is the existence of fasted cardio an affront to this program, which is the most efficient (and lasting!) way to burn fat.

  2. Excellent point. That is basically what I say in Part 3... except a little more long windedly (to make up a word).


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