Does Exercise Make You Hungrier - Part II

Last week I told you about a study where some participants exercised, some didn't and all of them lost about the same amount of weight. The investigators who led the study speculated that the active subjects were no better losers than the non-movers because working out seemed to make them hungrier; they ate more thereby offsetting any calorie burn advantage offered by the exercise.

From the comments I received, both here and on Twitter, I don't think I did an adequate job explaining what the results from this type of research really mean.

At the very least, I get the sense that people didn't like hearing that exercise may not help them lose weight. Let me start by saying that I don't like the thought of exercise being a weight loss dud any better than you do. But I am a firm believer in paying attention to what the science has to say.

Well designed studies often turns conventional wisdom on its ear, which can help you achieve your fitness goals. Why continue to spin your wheels if there is a better way? A classic example of this is stretching: For decades, experts used to believe that stretching before a workout would help you perform better and prevent injury. We now know (definitely) that the opposite is true.

So when several studies by respected scientists show that exercisers in the lab don't lose weight very efficiently if they also don't pay close attention to their diet, I think we should at least stop and consider why this might be.

As several of you pointed out, there are some flaws in these preliminary studies. None of them to date have measured body composition. In other words, investigators haven't tracked changes in how much of the participant's body weight consisted of muscle versus body fat.

As we all know, there is a big difference between two people of the same height and weight when one is a muscular gym rat and the other is a Doritos-obsessed desk jockey. (More on body fat percentage here.)

The researchers also did not bother to track exercise intensity. Some studies show an increase in appetite after low intensity exercise like a stroll through the park but a sharp decrease in appetite after high intensity or long duration exercise like a hardcore interval training session or a marathon -- at least for men.

From a physiological perspective, it could be that novice and/or overweight exercisers do indeed experience a keen sense of hunger after a workout whereas their leaner, more experienced counterparts do not. From a psychological perspective they may be more primed to use food as a reward for working out than someone who has dedicated years to staying thin and healthy. And of course, a lab is not the real world anymore than a treadmill is the open road.

When you actually try to lose weight on your own, any number of factors play a part in whether or not you succeed both in the short or long term. I suspect hearing that exercise does not help you lose weight made a lot of you so angry because quite frankly, this type of information doesn't apply to you.

If you are lurking on a website such as this or otherwise trolling the Internet for health information, by definition you are more health conscious than the average American to begin with and therefore – I'm just guessing here – more likely to exercise for all the right reasons and less likely to spoil the results with "reward overeating."

Instead of plucking people off the couch and prodding them to move for a few months, I would like to see researchers seek out lifelong exercisers to see what makes them tick. Then, after learning what secrets their bodies and minds have to offer, they should share these lessons with the 65 percent of other Americans who can't seem to shed weight or keep moving on a regular basis.

But even if we don't like the answer (or even the question!) I think knowing the possibility that exercise could make you hungrier is useful information. If you're just embarking on an exercise program and you really want to drop some pounds, it alerts you to the red flags so you don't sabotage your efforts. (Once again, I recommend keeping a diet and exercise log so you have a good sense of both eat and burn.)

Does hearing that exercise may not help you lose weight still make you angry or are you on board with me? Post here or tweet me.

If you are just starting out on an exercise routine, you may be interested to know how long it really takes to gain a pound of muscle.

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