man working out

Exercise and Recovery: Constrained Theory of Energy Expenditure

I came across this theory awhile back and I put off investigating it. Well it came around again and this time I spent the time to investigate. There is a growing database of research around this theory. For the longest time we assumed calories in, calories out. If you eat 2500 calories per day, you need to expend 2500 calories per day in order to not get fat. Taking a cursory look at this, it makes sense. If you eat 3000 calories and only expend 2500 calories you are going to get fat. The extra 500 calories has to go somewhere, right? Conversely, if you eat 2000 calories and expend 2500 calories you should lose weight. The problem is this is overly simplistic.

There was a study done in 2012 investigating the energy expenditure of Hadza adults in Africa. They are one of the last peoples who live a hunter-gatherer lifestyle. The study looked at 30 adults. The assumption was that they would expend a vast amount energy per day hunting and gathering compared to a moresedentary population.

“Hadza were highly active and lean, with body fat percentages on the low end of the normal healthy range for Western populations….Contrary to expectations, measures of TEE (total energy expenditure) among Hadza adults were similar to those in Western (U.S. and Europe) populations.” This is quite ground shaking and requires to reevaluate our current thinking.

The study further states, “Our results indicate that active, ‘traditional’ lifestyles may not protect against obesity if dies change to promote increased caloric consumption. Thus, efforts to supplement diets of healthy populations in developing regions must avoid inundating these individuals with highly-processed, energy-dense but nutrient-poor foods.” This goes back to my last article on insulin resistance. Calories in, calories out simply doesn’t work. The energy density has little to do with the obesity but the stimulation of the production of insulin.  They continue, “processed, energy-dense foods have been linked to insulin resistance and cardiovascular disease among Australian foragers transitioning to village life.” And there it is, insulin resistance. For more on that check out my other article.

As you can see the results of this study are counterintuitive to what we may think, supporting the evidence that obesity is strongly linked to insulin production. Pontzer and his crew of researchers have termed this the constrained total energy expenditure model. The idea is as we increase physical activity at low levels total energy expenditure increases. However, at higher levels of physical activity, total energy expenditure levels off, plateaus. The body seems to have range for total energy expenditure. Below compares the old model, additive, to the new model, constrained.

At higher levels of physical activity you shunt energy from the “other” category. Let’s look into that a bit more.

So what is in the “other” category. We may simply shunt energy away from certain behaviors, they state. We may sit more than stand, fidget less, but we may cut into more metabolic activity too. Studies have shown a reduction in basal metabolic rate, somatic repair, growth,  suppression of ovarian activity and lower estrogen production.

This is not to say we shouldn’t exercise. We have too many studies showing benefits of exercise. Movement is life and very important in keeping a healthy brain. But if we weight loss is your goal, exercise is not going to cut it, not like diet. 95% of it is all about diet. You cannot outrun a bad diet!

I have had too many patients and too many friends who go to gym every day for hours trying to lose weight or get healthier. But in the end the diminishing returns will set in and they will fail. We have to be careful comparing ourselves to others. Some can compensate very well, but even they have their limits.

For several years I would go with my buddies to the gym and lift a lot of weights. We would go almost every day of the week. It was intense. I put on a lot of muscle weight, though you cannot tell since I am a pretty tall dude. I graduated high school at 145 at 6’5″. After several years of bodybuilding and strength training I weighed 210. I noticed something during those years of training intensely. I had to use more and more preworkout to motivate me and provide the energy needed for the workout. 1 scoop of preworkout typically has about 150 mg of caffeine or more. I started doing 1.5 and then 2 scoops sometimes and I was still tired! But I continued to workout for a time. During that time I also started getting more sinus infections and migraines, not directly related, but I am sure my system was pretty taxed. During my doctoral training I ultimately gave up on working out. My wife and I would walk regularly but that was about it. Some of this was due to other illnesses I didn’t know I had at the time, but nevertheless I had more energy after I stopped.

That brings me to this year. I started exercising again, lifting pretty heavy 3 times a week. The result? The same thing happened. Over the course of a few months I gave up gradually. I started only going twice, and then once, and then not at all. Before this time, the illnesses previously mentioned were taken care of so they were no longer a factor. This is about the time I came across the constrained model again. Perfect timing, I was ready.

Much of what I read and wrote earlier made sense. I was already intuitively thinking of them. Exercise has been a tremendous study of mine over the last several years and this is really the culmination of that study. Which leads me to my next point.

One of my big hobbies is studying personality traits. I started with Myers Briggs Typing but since moved on to more of Dr. Carl Jung’s original work focusing on the 8 cognitive functions. The theory is that we use all 8 but rely on some more than others. In fact, we have a dominant function and an auxiliary function. My dominant function is introverted intuition and my auxiliary is extroverted thinking. I won’t go into this too much, but suffice it to say I am in my head a lot, thinking and pondering on various abstract topics, patterns, and perspectives. And when I say a lot I mean a lot. And when I say thinking, I really mean thinking. Not what I am going to get from the store or other routine things, but the deep patterns of things. This is normal to me, just how I am. But it dawned on me that all this thinking takes a tremendous amount of energy. I have noticed when I exercise intensely and frequently I am too tired to think. I just want to sit and binge watch a show or something. Again supporting the constrained model.

So let’s talk about energy. We need energy for 3 functions: vitals (what keeps you alive), physical activity and stress, and recovery and maintenance.

  1. Vitals: This is our essential function. Our heart needs to beat, our neurons need to fire, and our lungs need to work. We need our vital functions to live.
  2. Physical Activity, Everyday Activity and Stress: All our movement and stress fall here. The more stressful our life is and the more we workout the greater this becomes.
  3. Recovery and Maintenance: Whatever we choose to do requires maintenance and compensation. If we exercise we use up glycogen stores and we need to recover. If we are sick we use up nutrients and energy fighting off the illness. Digestion can even be shunted away from during periods of high stress. This can further hamper recovery and maintenance.

So the more we exercise, the more we take away from recovery. The more we spend time thinking, the less we have for 3. You cannot rob Peter to pay Paul. It may be a sickness like my sinus infections or mistakes at work, but the payment always comes due.

So what can be done? Is it as dire as it sounds? No, just something to be aware of so you do not overtrain and compromise other body systems. The days of training til you puke need to be gone. The give it all you got every day to reach your goals needs to stop. The goals will be achieved by the few, but for most of us we will fall short if we train too hard for too long.

Dr. Phil Maffetone is a great example. He trained 6 time champion of the Iron Man, Mark Allen. Dr. Maffetone’s approach is to improve aerobic activity by exercising, specifically running, at your maximum aerobic function. The MAF method is simply keeping your heart rate at about 180-age. There are some caveats to it but that is about it. Listen to this video of him discussing some of this.

He wrote a book on how breaking the marathon record will happen. It will happen when athletes stop training so long and hard. Of course he throws in our natural running gait too, that is, running barefoot.

So what is my recommendation? Take time to recover. Mark Sisson has a great book called Primal Endurance where he breaks down a lot of this including the MAF method. It is a good read. He has some great info on his website. But essentially it is this, strength train a 2-3 days a week watching your heart rate so the exercise is not too intense, sprint every 7-10 days, and move at a low aerobic rate whether it is jogging, walking, swimming, or hiking for about 5-7 hours per week. There is more to it, but it is a nice summary. Adapt and change it for your own situation. But exercise should not be grueling, but enjoyable.

Life is meant to be enjoyed.


  1. Pontzer, et al. Hunter-Gatherer Energetics and Human Obesity.
  2. Pontzer, et al. Constrained Total Energy Expenditure and Metabolic Adaptation to Physical Activity in Adult Humans

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