You can’t outrun your fork, sorta speak, because your body’s metabolism readjusts to increased exercise. As a matter of fact, it does that with calories too. Learn why, and what to do about it.
THERE’S THIS thing called “Homeostasis” and although it may seem unfamiliar, you have experienced it throughout your life. Homeostasis is the regulation and maintenance of our body’s internal environment within certain narrow ranges that support life, irrespective of changes in our external environment.
Take temperature and doughnuts for example. You may be walking through a snowstorm, but your body will do its utmost to keep your body at 96.8 degrees. Or when you eat that doughnut causing your blood sugar to spike, your pancreas will detect this imbalance and secrete insulin to cause liver cells to “take up” this sugar in the blood. That sugar in that doughnut is acidic which may cause your blood pH to become too acidic, and thus your lungs and liver will act to bring down this acidosis in order to get pH down to the ideal acid/alkaline level of 7.40.
Adjusting to cold weather and sugar are examples of homeostasis in action. Without this mechanism, you would freeze, become diabetic and sick much faster.
Unhappily, this is also true with exercise and calories because of this thing called “Metabolism”. Metabolism is the mechanism of homeostasis that you have experienced every time your exercise or diet regimen has stalled and is no longer making you stronger, fitter or leaner.
In a Forbes article by Nancy Fink Huehnergarth entitled Why You Can’t Exercise Your Way To Weight Loss, anthropologist Herman Pontzer explains that our bodies adapt to physical stress, like exercise, such that exercising more vigorously does not necessarily result in more calories burned. He conducted a study of 300 men and women and found that people with moderate activity levels expended only 200 more calories per day than those with sedentary lifestyles, and that the most physically active people expended the same amount of calories each day as people who were only moderately active. (1) 1
Now, before you couch potatoes (try to) leap up and high five each other, please understand that although Dr. Ponzer’s research offers an explanation why so many people who initiate an exercise program alone lose little or no weight, it does not mitigate the other critical benefits of regular exercise, such as the decreased risk of cardiovascular disease (the number one cause of death in the U.S.), depression and type 2 diabetes (now considered a health epidemic in the U.S.).
“Exercise is really important for your health, said Dr. Pontzer. “That’s the first thing I mention to anyone asking about the implications of this work for exercise. There is tons of evidence that exercise is important for keeping our bodies and minds healthy, and this work does nothing to change that message.” (2)
Inevitably, some people who read this will think of a few people they know that eat like pigs, but by virtue of their exercise, stay thin as a rail. For me, ultramarathoner Dean Karnazes comes to mind.
Mr. Karnazes is basically inhuman. His extreme athletic endeavors includes running 50 consecutive marathons, one each day, finishing with the New York City Marathon in three hours flat. Dean has been known to have multiple pizzas delivered to him at set points along his long runs. He folds them up and chows down, and yet he stays very lean.
Dean is an outlier, and as such Dr. Pontzer’s studies, and the others I’m about to share with you are not relevant to him. And if you do, or intend to, exercise like Dean, I suggest you go find yourself a good massage therapist and dispense with reading the rest of this article.
For the rest of you, realize that Dr. Pontzer’s conclusions are not unique to his research; consider these six collected by Ms. Huehnergarth: (1)
As an avid exerciser, I admit that these findings mess with my sensibilities, but unless you’re an outlier like Dean Karnazes, it makes sense to consider the evidence. In this case, the evidence supports what we might have guessed if we kept our understanding of homeostasis and metabolic adaptation in view – the body will try to adjust to new inputs such that it maintain its estabished norms.
Let’s dig into this metabolic adaptation relative to weight loss, and for this I’m going to refer to an article called What You Need To Know About Metabolic Adaptation written by Eric Trexler, a strength coach and power lifter.
Mr. Trexler points out that when there’s a caloric deficit (more caloric energy is expended than consumed), you lose body weight (hopefully fat rather than muscle, which you can help ensure by ingesting adequate protein and doing resistance exercises.) This means that the body’s energy supply is low, and the body responds by adapting to it in three possible ways by:
These three responses are the body’s homeostatic response to caloric deficit through the mechanisms of the mitochondria (the cell’s “energy powerhouse”), metabolism and hormones.
The result is that weight loss slows down or stops.
At this point, the insightful of you may blurt,
“Hey Joedude, isn’t this homeostasis thing messing with a favorable metabolic response both to exercise and a reduction in calories?”
Ah, insightful, grasshopper. Yes, it does. So let’s explore a solution.
You can’t outrun your fork, as they say, but perhaps we can tune the fork and the run.
Say you begin a diet, start exercising or both. If effective, your diet will ensure that you’re consuming fewer calories than you’re expending, and your exercise will amplify the caloric expenditure. All is well for a bit, but eventually the dreaded metabolic adaptations occur which winds up slowing or stopping your weight loss, whether from diet and/or exercise.
What do you do?
You mix it up!
Mixing things up confuses homeostatic mechanisms. If you were to consistently to lift 30 pounds above your head and it was initially hard to do, your muscles would respond by getting stronger and larger. At some point, however, 30 pounds would no longer be challenging and your strength and muscularity would plateau.
One or all or all of those three adaptations listed above would happen, and what you would need to do to disrupt such adaptations is to disrupt what you’re consistently doing – lifting that 30 pounds, or whatever. Maybe you’d start lifting 40 pounds above your head, or lifting it at different angles, cadences, repetitions, number of sets, time between sets, etc.
Given that lifting a weight above your head does not constitute a balanced exercise program, let’s apply this “mix it up” strategy to what you might actually do for exercise.
I like what Andrew Read over at BreakingMuscle.com has to say about training variables. He lists four you need to consider as pertain to resistance training (calisthenics or weight lifting):
You would mix this up by choosing an exercise program with a defined selection of these four variables and stick with it for a month or so, and then change things up for the next month, etc.
Perhaps cardiovascular conditioning is more your thing than resistance training. Consider mixing up your exercise program like this, doing each on separate days or in combination if well tolerated, and focusing on a consistent set of exercises for a month or more before mixing it up for the next month, etc.:
Likewise, you would take a diet based on consistent caloric deficits, and shake it up. Among the things you could do with a diet is:
What you need to remember is that your body wants to conserve energy. For most of our evolution, we weren’t awash in convenient food and couches, but rather experienced sustained periods of fasting and moving about to find food. There would be no human beings if our bodies were not able to conserve energy during such lean times.
Fast-forward a few thousand years. Now two-thirds of us are overweight and don’t move much. Our bodies have adjusted to this, and will adjust to any changes in that status unless your regularly mix it up.
Any questions or comments?
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