The story of Sisyphus in Greek mythology describes how the gods punished a malevolent and deceitful king by making him endlessly push a boulder up a hill, only to have it roll down again. One can’t help but see a parallel between Sisyphus’s futile endless struggle and the fruitless efforts of unsuccessful gym-goers and yo-yo dieters who, rather than gaining inches in their journey toward fitness, often end up gaining inches on their waistlines.
So will it be Jill Michaels — personal trainer to the stars — to the rescue? Nope, just a basic understanding of metabolism.
A more in depth understanding of the interplay between our fat storage process and our energy use process will quickly expose why going to the gym to burn fat is very inefficient.
The first thing to consider is a set of processes that people are only vaguely aware of: basal and daily metabolic rates.
Basal metabolic rate, or BMR, is defined as the amount of energy needed to sustain basic life processes at rest. For example, it is the energy you use to sustain yourself at 4 am, when you are asleep and in a fasted state (i.e., you haven’t eaten in a while and your body isn’t dedicating any energy to breaking down food).
While you are sleeping, 60 percent of your total energy needs are for powering your brain, liver and skeletal muscles, your heart and kidneys require 20 percent, and the remaining 20 percent is dedicated to miscellaneous processes.
Clearly, your body is busy at work even when you are not. So what does this work entail? Definitely not moving around. Imagine yourself at 4 am. You might toss and turn a little bit, but for the most part you are stationary.
The energy used by your organs while you are at rest manifests in a number of processes, all of which are not what we typically imagine when we think of energy use. In fact, roughly 90 percent of this energy use is for biochemical reactions! This includes anabolic reactions (e.g, building proteins from amino acids) catabolic reactions (e.g., breaking down glycogen to glucose). In addition, it entails maintaining ionic gradients within the cell, mostly in the form of the Na+/K+ pumps and Ca+ channels that sit in the cell membrane. Together, these processes keep the cells of your organs alive and functioning as they should, so that these organs can perform their vital roles and sustain life.
Most of your daily energy use is not for moving around with muscles. It’s for moving ions across cell membranes (~90%)
By Bruce Blaus (Own work) [CC-BY-3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
It’s easy to overlook energy use at rest if you are predisposed to thinking of energy use in terms of moving around, be it walking, running, lifting weights or shoveling your driveway. After all, the notion that 90 percent of our energy use is dedicated to biochemical reactions while we are sleeping is one thing, but what about when we wake up and get going? The energy we use for physical activity surely must amount to more than the energy we use for biochemical reactions!
False. This is where we need to flip our intuitive notion of energy use upside down and face the facts. The average total daily energy expenditure for a physically active person (the type that might go to the gym three to four times a week, hit the elliptical and read Cosmopolitan magazine) is ~2500 calories. Of that 2500 calories, only 30 percent is used for physical activity, and this includes the energy used during that hour on the elliptical. Another 10 percent or so is used to digest food. That leaves a whopping 60 percent of energy use dedicated to our basic life processes, the same at rest processes described above. It doesn’t take a doctorate in advanced mathematics to see that the greater part our daily energy use, even if we religiously go to the gym, is for biochemical reactions.
Just fueling the basic processes that keep us alive, even at rest, requires more energy than you could reasonably use while working out! This brings us to the second thing we need to consider, a concept we all know well: excess calories from food will inevitably form fat stores.
Fat storage represents a mismatch between energy availability and energy use. It’s a valuable tool evolutionarily — just ask your friendly neighbourhood grizzly bear who eats as much as possible during times of plenty in order to store fat for sustenance during hibernation. While hibernation is an extreme form of energy scarcity, fat stores equip all animals for times when there is nothing to hunt or nothing to graze on. In fact, fat storage is a mechanism that largely evolved to anticipate periods of starvation. It’s primary function is to fuel the body, including all those microscopic biochemical processes, when there’s nothing to eat. The majesty of this mechanism is that it applies to humans just as much as it applies to foraging deer when the grass isn’t all too green or the wolf pack on the hunt when prey is elusive or scarce.
It’s a simple relationship: eat food to build fat stores, don’t eat food to deplete stores. Again, this turns conventional wisdom on its head: don’t we need to eat every day to fuel our body? No. For 99 percent of our evolutionary history we ate irregularly, with times of feast and times of famine, and we adapted accordingly. It does not compromise our health to go without eating a day or two — it’s a pattern of behavior that is in line with our evolutionary design, unlike eating three meals a day on fixed intervals. We metabolize fat stores during times of fasting, our liver stores enough fat soluble vitamins (vitamins A, D, E and K) to last three weeks; water soluble vitamins (B and C) need to be replaced after two weeks. And — to dispel the biggest myth — we don’t use our own proteins as an energy source until true starvation, which occurs approximately after 40 days of fasting. Finally, in periods of fasting the body looks inward to dispose of and recycle defective cells in a process called autophagy or ‘self-eating’, freeing up precious biomolecules and ridding the body of broken down cells — addition by subtraction.
Again, after a day or two of fasting,* our bodies are using fat stores primarily to fuel processes that having nothing to do with moving around. (*Most studies of fasting have been done on animals.)
There are many strategies to diet, exercise and weight loss. If we bring the conversation back to how exactly our body uses energy, and if we view our dietary and eating patterns ‘under the light of evolution’ there is a strong argument to be made that fat loss happens easiest when we are fasting doing nothing!
Final note: Of course it goes without saying that even though working out is an inefficient weight loss strategy, exercise is by no means useless. Physical activity is an essential component of health and well being; after all, we are built to move. Numerous studies have demonstrated the benefits of physical activity in curtailing many of the diseases of affluence that plague us today, including diabetes and coronary artery disease.
1) Boron, Walter F., and Emile L. Boulpaep. Medical Physiology, 2e Updated Edition: with STUDENT CONSULT Online Access. Elsevier Health Sciences, 2012. – Chapter 10, Metabolism
2) Food Intake and Starvation Induce Metabolic Changes:http://www.ncbi.nlm.nih.gov/books/NBK22414/ (Describes energy use. Dispels protein metabolism myth. Differentiates starvation from fasting.)
3) Poehlman, ERIC T. “A review: exercise and its influence on resting energy metabolism in man.” Medicine and Science in Sports and Exercise 21.5 (1989): 515-525.
—A breakdown of daily energy expenditure.
—The Biochemistry of metabolism:http://en.wikipedia.org/wiki/Basal_metabolic_rate#Biochemistry
“Metabolic Homeostasis“ (Describes how 90% of energy use is for maintaining ionic gradients.)
“Therapeutic Fasting and Cancer Prevention” (Differentiates starvation from fasting. ”
Autophagy and Autolytic Cannibalism” – A Thermodynamic Approach to Cancer Prevention. (Describes the role of the fasted state and the initiation of autophagy)
5) Recommended Reading: Eat Stop Eat, Brad Pilon: Effectively integrate resistance training and intermittent fasting for overall health and well-being.
Provided by Egiroh Omene