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So, what’s the skinny on calories?  Do they really matter or have your efforts to meticulously record every last calorie on your SlimKicker account been in vain?  Well, the short answer is yes and no.  They do matter, but fortunately for your brain, a calculator or a calorimeter aren’t necessary.

First off, a little background on the foremost health buzzword of our time: the calorie.  I’ve always found it odd that for a word so widely used, so few people actually know what it is.  In 1824, French chemist Nicolas Clement defined a calorie as the approximate amount of energy needed to raise the temperature of one gram of water one degree Celsius (though for our purposes a unit of energy will suffice).  All of the food we eat has a caloric value which equates to the amount of energy it provides to our bodies.  Over the course of a day all of the calories we ingest are either stored, burned or excreted, and as I mentioned above with the first law of thermodynamics, the net gain or loss translates to the change in our weight.  Everybody still with us?

scaleNow given how fundamental the calorie has become to our perception of health, eating and exercise, it’s not a stretch to say that for many, a de facto 11th commandment would be, “thou shalt count thy calories”.  But if calories and calorie-consciousness are so intrinsic to our health and weight, how is it that until the latter half of the 20th century few of us even knew what one was, let alone kept a daily running tab?  That’s right, for the bulk of human history we managed to survive sans calorie-counting and maintained relatively low rates of overweight and obesity.  Yet, in the past half-century since adopting this dubious practice we’ve managed to cement ourselves as the fattest nation on the globe.  Now, I’m not saying our new-found obsession with the calorie is the cause of the obesity epidemic, but is it not fair to say that it would be irrational to think it’s the solution?

Of the two prevailing hypotheses involving weight-gain, the positive caloric balance is easily the most pervasive, due in large part to the fact that the government adopted this view in the 1970s.  Eat too much, exercise too little, gain weight: it sounds so logical it seems undeniable.  In this hypothesis overeating and inactivity (hunger and lethargy) are the causes of weight gain.  It suggests that the problem is merely a behavioral one; we choose to eat Swizzle-Stix and chug Mountain Dew incessantly and/or lounge in our Laz-y-Boy for hours on end watching Honey-Boo-Boo marathons.  To fix this, we must create a caloric deficit by eating less and/or expending

Resistance is futile, eat the sketti!

Resistance is futile, eat the sketti!

more energy.  Now, underpinning all of this is the notion that intake and expenditure are independent variables; in other words, we can change or manipulate one of them without any effect on the other.  For instance, this rationale suggests one could drastically cut calories (eat less) while at the same time upping their expenditure (exert more).  To quote Gary Taubes, it is “almost impossible to overstate the extent to which this hypothesis now pervades all thinking and research on obesity and weight, and underlies every accepted method of treatment and prevention.”  Does this logic sound plausible to you?

If not, fret not!  For the past century there has been an alternative to this hypothesis, one that is inclined towards a physiological, not behavioral, explanation.  Let’s remember that far from just an excuse to stuff our face with some sweet tasting confection, eating has a real function, to fuel our body and its many cells.  Hunger, therefore, is not a phenomenon of the brain or a matter of willpower as is often perceived, but a response to a lack of fuel and an effort by the body to replenish your energy supply.

So let’s suppose that upon eating, something was causing those calories to be locked away as fat in our adipose tissue, preventing them from being used for energy by the body.  What would happen?  Well, for starters, the fuel deficit which prompted your appetite to begin with would persist.  This would trigger hunger, of course, but also inactivity, because in the absence of adequate energy stores your body’s natural response is to fiercely conserve what energy it does have.  This would then induce more eating, and though it may satisfy our hunger, this would only be temporary.  The metabolic defect would redirect much of the energy to our fat tissue and in a matter of hours hunger would rear its ugly head again, and the vicious cycle would repeat itself.  As a result, energy levels would fluctuate wildly, hunger pangs would be frequent, and weight would be almost impossible to control.  Sound familiar?


So what could cause such a defect to exist?  Well, if indeed obesity is a disorder of fat accumulation, the answer would lie in whatever it is that  regulates fat accumulation.  In this case, it’s the hormone insulin.  When we eat sugar-laden, easily digestible foods our blood sugar spikes, leading to a coincident rise in insulin, whose job it is to take glucose (sugar) out of the bloodstream and deposit it in the body’s cells.  Under normal circumstances – eating traditional foods with moderate amounts of sugar and fiber to go with it – this process occurs routinely without a hitch.  However, the past century has seen a dramatic increase in the amount of processed, sugar-rich foods.  Digestion of such foods is very problematic for our bodies, and the repeated surges in insulin which accompany the rapid digestion of such foods result in the loss of sensitivity of our cells to insulin.  And when the cells lose insulin sensitivity, the glucose in the bloodstream has to go somewhere.  That somewhere is often our adipose tissue.  Now this is a normal process that occurs in all people daily as a way to temporarily store energy reserves.  The problem arises when more energy is coming in than going out, that’s when weight begins to rise.

Given this bit of information, understanding why modern peoples struggle with weight when our ancestors managed to remain relatively thin with apparent ease becomes much easier.  It isn’t simply a matter of gluttony and sloth, of eating too much and being inactive.  Something changed in our environment which led to those behavioral and physiological changes: it was our food.

cakeIn light of this, our approach (by our I mean the government, public health authorities, doctors, trainers, just about anybody who gives diet and health advice) to combat excess weight seems rather…well, ill-conceived.  Catch phrases like “a calorie is a calorie” and “calories-in, calories-out” were adopted, ostensibly, to simplify a complex subject for public consumption; but in doing so they fostered fundamental calorie-related myths in generations of Americans that have played a key role in the obesity epidemic.  Stating that one must burn more calories than they ingest for weight-loss is fine but it misses the point.  It suggests that the responsibility of monitoring this balance should fall to the individual, which seems an unnecessary burden considering no society in history ever bothered dealing with it.  Secondly, it creates a calorie-republic, where all calories are thought to be created equally and your only concern should be to limit your intake to a certain number.  This certainly isn’t the case and is evidenced by the various ways in which our bodies react to, and metabolize, certain macronutrients.

The bottom line is this: calories have taken on a persona akin to that of fat and cholesterol as the arch-enemy of health-loving creatures.  But of course, they aren’t the enemy any more than fat or cholesterol, or water or vitamins for that matter; they are essential to life.  The only thing one should really focus on is the quality of calories eaten, not the quantity.  If you’re eating the right foods, the quantity takes care of itself.

» Revisit the Causality of Obesity, Peter Attia

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