April 23, 2014

Calories In, Calories Out; Calories, Schmalories, All About!

You put your calories in, you put your calories out, you put your calories in and you shake ‘em all about!

Oh, wait, that’s not human physiology, that’s the Hokey-Pokey, and it probably hasn’t been part of your daily routine since you were about four years old. Most of us have grown out of this kindergarten dance (at least, in public), so why does so much of the nutrition and dietetics community still cling to outdated (not to mention flat-out inaccurate) ideas when it comes to the care and feeding of the human body? Maybe brainwashing, maybe herd mentality, maybe fear of stepping outside the mainstream. Maybe fear of upsetting their corporate sponsors. (The Academy of Nutrition and Dietetics [formerly the American Dietetic Association—the body responsible for credentialing registered dietitians] is proudly bankrolled by the likes of Pepsico, Coca-Cola, General Mills, and other producers of such fine, nutritionally sound products as Chocolate Lucky Charms, Doritos, Cheetos, and Fritos.)

Since I don’t have any corporate sponsors (but am open to the idea, hint, hint <--No, just kidding), gather round, kids, and I’ll tell it like it is. If I were Foghorn Leghorn, Id say something like, Gather round hea, and lemme, I say lemme learn ya somethin about appetite and metabolism.

Regular readers of this blog (all three of you) will recall from my post about “vegetable oils” that I’m a fan of thought experiments. I like them because they invite us to think about complex things in simple ways, and usually allow us to draw conclusions that are stunningly logical, but which we probably wouldn’t have come up with on our own.

Admit it—you know exactly 
what I’m talking about!
So let’s kick off this series about calories, human metabolism, fat loss, and fuel partitioning with a helpful thought experiment. (Why am I writing about these things? Check out these posts for my explanation: first, second, and third.) Picture it: you’re at the Chinese buffet. (If it’s been a few years since you’ve been to one of those, think back. I know you’ve had this experience.) Okay. So what happens? You load up a plate with food, polish it off, then go back for seconds, and maybe even thirds…or fourths! By the end of the evening, you’re so full you could swear you have to be rolled out into the car. You announce to anyone who will listen that you’re not gonna eat again for three days. And rightfully so. In terms of “calories,” you’ve probably just consumed enough to last you about that long.

But what happens next? Mere hours later, you’re hungry again! What gives?! Is it possible that the thousands of calories you ingested were somehow not enough to keep you satiated for a few hours, or is it more likely that all the rice, noodles, dumpling wrappers, deep-fried batter, and sauces made with corn starch and sugar have interacted with your body and influenced your physiology in such a way that even though you just ingested multiple days’ worth of “calories,” you have the urge to eat again just a little while later?

With that in mind, can we agree, right here at the beginning, that maybe, just maybe, there’s more governing how much, how often, and what we’re driven to eat than the number of “calories” in our food? (I’m going to stop putting calories in quotes, because it’s gonna get old. Maybe you’re thinking it already has. Anyway, picture me saying it that way as you continue reading.)

I’ll assume now that your answer is yes, and that we can assume there’s more to this story than calories in. So then, what about calories out?

“The tragedy of science is the slaying of a beautiful hypothesis by an ugly fact.” (T. H. Huxley, English biologist, 1825-1895)

This is not the only way to get 
“calories out.”
Something that frequently bugs me when I read studies about weight loss is that when They (capital T) use the phrase “calories out,” they’re almost always referring to dedicated physical movement that is known to expend calories: walking, jogging, cycling, swimming, weightlifting, soccer, animalistic sex, hockey, tennis. Sometimes they even include things like fidgeting: tapping your toes, drumming your fingers, things like that. In physiology nerd circles, this is known as NEAT—non-exercise activity thermogenesis, i.e., burning calories through activities other than what we think of as “exercise.” (I think there might be a little something to NEAT, but not much. I’m sorry, but incessantly clicking one of those clicky pens is not going to make the difference between a body at 150 pounds and that same body at 300 pounds. I mean, really? Imagine how long you’d have to drum your fingers to burn off a Twinkie. You’d probably sooner wear a groove in the table than burn off even half the cream, but I digress.)

What researchers rarely seem to mention when they talk about “calories out” are all the processes that happen in our bodies that burn calories, but over which we have little—and in some cases no—control. To be more accurate, these processes don’t “burn calories”; they require energy. Specifically, they require ATP. (Oh no! An abbreviation vaguely familiar from high school science class! Don’t get scared. All will be explained in due time. [Can't wait and youre bored at work? Or need help falling asleep? Watch this.])

See, conscious effort aimed at moving our bodies isn’t the only way we expend energy (calories out). Our bodies expend loads of energy just to keep us alive, even while we sleep. All of the following require energy to happen, and this is just a small sampling: breathing; your heart beating; your eyelids blinking; the contraction of the smooth muscles lining your intestines that help propel food along your GI tract; your renal tubules (kidney cells) filtering your blood; the sodium-potassium pumps embedded in your cells that pump ions and electrolytes in and out. Pretty much every teeny, tiny thing that goes on inside you, whether you’re aware of it happening or not, requires energy. That is, it “burns calories.” This is your basal metabolic rate (BMR). The number of calories (quote, quote, hehheh) your body burns when you are doing jack squat. This is the minimum number of calories your body needs just to keep you functioning and maintain your current body composition.

This basic, rock-bottom, bare minimum number of calories needed to keep you on this side of the ground is why there are such wide variations in BMR from person to person. Do you think a 240-pound football player—with his many, many more pounds of muscle (and all those individual muscle cells’ accompanying ion pumps), likely slightly enlarged heart, and larger amount of skin to cover all that extra tissue—could stay alive on the same number of calories as a 110-pound medical transcriber who sits in front of a computer twelve hours a day? (Well, possibly, if the football player stopped playing football and all his muscle atrophied, but you know what I mean. He couldn’t maintain his current size and strength and feel well on the same number of calories the transcriber does just fine with.)

Let’s think about this just a little more deeply. The fact that our bodies burn calories expend energy by performing metabolic and physiological tasks over which we have no conscious control is part of what makes it so indescribably difficult to determine exactly how many calories someone requires compared to someone else, and how much of a caloric deficit (if any, but more on that in another post) someone would need to create in order to “lose weight.” (Note: if you can look at the formulas in that link without screaming in horror and/or fear, you should consider a career in advanced combinatorial mathematics. Perhaps the NSA is hiring. Seems like they always have lots to do…)

If you’re a Zen master, perhaps you’ve cultivated more conscious control over some of these otherwise “involuntary” processes (heart rate, GI motility, etc.) than the average schmuck. For most of us, though, we can’t much influence the “calories out” part of the equation that includes all the chemical reactions that happen inside us. And it’s darn near impossible to figure out just how many calories, exactly, your heart burns every time it beats, how many calories, exactly, your eyelids burn each time they blink, or how many calories, exactly, your stomach burns when the muscles that surround it contract to churn your food together with stomach acid. This is what Jonathan Bailor means when he says something like, “Calories count, but that doesn’t mean we have to count calories.” (I’m paraphrasing. You can check out good interviews with him here and here, but Ill explain what he means in a future post.) And, in fact, we can’t count calories out, for the reasons I just explained. It is virtually impossible to determine the precise number of calories any one of us, as an individual, “burns” during any particular activity, let alone when our activity levels differ greatly from day to day.

I feel your pain, dude.

This is why the “calories burned” feature on cardio equipment at the gym cracks me up. (When it’s not too busy infuriating me, that is. Either way, it’s ridiculous. Ridiculously funny and ridiculously stupid.) How does a treadmill, bike, or stairclimber know how many calories I, Amy, burned during my session? If it uses an algorithm based on the speed, intensity, and duration of my workout, it can land on a vague, vague ballpark. If it goes a step further and asks for my age, height, and weight, maybe we get a narrower ballpark, but it’s still a ballpark. Will I burn the exact same number of calories as a woman (or man, for that matter!) of the same age, height, and weight, who works out for the same amount of time at the same speed and intensity? Please, please, do not rely on those calculators. I hope you’re starting to see how laughable this all is.

That’s enough for today, I’d say.

If you remember only one thing from this post, let it be this: we are generating “calories out” all the time. Not just when we’ve specifically set aside time during the day to exercise. If your heart is beating, you’re breathing, and your brain has any sort of function registering, congratulations, you’re burning calories using energy!

Continue on to the Fuel Partitioning 101 Series: Fuel Partitioning 101: Human Body as Hybrid Car

P.S. Maybe you’ve heard the term “negative calories” in association with foods like lettuce and celery. This means your body expends more energy to digest and assimilate these foods than the number of calories they provide. Does this mean you could eat nothing but celery and cucumbers for two months and lose weight? Yes, but I don’t recommend it. That is not how you want to lose weight. ‘Cuz you won’t just lose fat, which is what you want to lose. You’ll lose muscle tissue as well [and probably even some bone mass], and that is bad, bad metabolic news. More on that in a separate series I have in the works.

Remember: Amy Berger, M.S., NTP, is not a physician and Tuit Nutrition, LLC, is not a medical practice. The information contained on this site is not intended to diagnose, treat, cure, or prevent any medical condition.


  1. When you eat low calorie foods like cucumber, tomatoes, oranges, broccoli, carrot, cabbage, lettuce etc., you consume very little calories compared to other regular food

  2. Really look forward to your posts!! Btw I checked Cheesetique and it looks amazing!!