Why care about calories?

After the last blog post on calorie magic, my husband–whose intellectual response to people challenging me on the internet is to want to give them a virtual wedgie–asked me why I didn’t just engage those cute little white dude-o-scientists who are so pumped about how IT JUST MUST BE CALORIES CALORIES CALORIES CALORIES in some sort of PubMed duel to the finish.

My explanation:  I don’t do PubMed duels. PubMed is a wonderful thing, and the internet has given us tremendous access to a great deal of information, much of which is used to confirm our own preconceived notions, even if (especially if?) we don’t fully understand what those notions actually are. As I’ve said before, a pastiche of  PubMed citations frequently boils to a bunch of snapshots taken out of context of the larger literature–and out of context of a full understanding of physiological and biochemical realities, not to mention social and cultural ones–that may or may not express a physiologically significant or practically useful concept.

And this is problem: I’m not convinced that calories express a physiologically significant or practically useful concept. Here’s what I figure. If calories were so FREAKIN important, then my biochemistry books should be rife with information about them. But that does not seem to be the case.

[I took my first biochem class at age 45, weeping my way through one excruciatingly difficult exam after another. I emerged–bloodied by unbowed–to joyfully sign up for 3 more semesters. I don’t consider myself an expert by any stretch; I just feel that biochemistry is sort of the key to the universe, certainly the universe of nutrition. If something doesn’t make sense from a biochemical perspective–which would apply to about 90% of the Dietary Guidelines–it shouldn’t be part of nutrition policy.]

I did this a while back, just for my own peace of mind, and I don’t know how useful it will be to any of you, but here’s what my collection of biochem books has to say about calories. Spoiler alert: Not much. [So you can stop here if you have a life.]

My biochemistry books, in order of how much I love them, least to most:

Advanced Nutrition and Human Metabolism (3rd Edition), 2000

James Groff & Sareen Gropper

I don’t know why I have this book.

–“Calorie” is indexed to a passage on units of energy in a discussion of thermodynamics. Calories are not mentioned again.

–“Calorimetry, direct” and “calorimetry, indirect” are indexed to passages discussing the measurements of energy expenditure. It contains this notable summary:

” Although changes in energy balance produce weight changes, the extent of these changes varies from person to person.”


Functional Biochemistry in Health and Disease, 2009

Eric Newsholme & Tony Leech

I got this book with great anticipation, as it seemed to promise a better integration of biochemistry and physiology than most biochem texts. But like some sort of weird Asian-fusion spicy wonton Alfredo dish, I guess it is just trying to do too much. There is not enough detail here for me, and the reader is left to sort of assume “magic elves in a box” in too many places, which–as far as I am concerned–defeats the whole point of learning biochemistry.

–“Calorie” is not indexed.

–“Calorimetry” is indexed. This couple of pages highlights the limitations of measuring calorie expenditure in the human body.

Biochemistry (4th Edition), Lippincott’s Illustrated Reviews, 2008

Pamela Champe, Richard Harvey, & Denise Farrier

This is the boy-toy of my biochem texts. I don’t love this book, but it is much more portable than my other biochem texts, so I can take it out in public without too much embarrassment.

–“Calorie” is not indexed.

–“Caloric consumption,” “caloric restriction, weight reduction and,” and “calorimeter” are indexed.

“Caloric consumption” addresses the fact that the source of the increase in calories consumed by Americans since 1971 is carbohydrates.

“Caloric restriction, weight reduction and” is indexed to a page includes the following helpful information:

 “Caloric restriction is ineffective over the long term for many individuals.”


Biochemistry (2nd Edition) , 1995

Donald Voet & Judith Voet

I approach the Voets with the reverence and respect due a giant doorstop of a book like this. Like that scary old professor who knows everything, it is intimidating, but, well, it knows everything.

“Calorie (cal)” and “Calorie, large (Cal)” are indexed to the same place. The indexing refers to a table that compares thermodynamic units and constants as an adjunct to a passage on the First Law of Thermodynamics. This passage contains a little nugget of joy for those of us who insist that conversations about weight management may need to consider more than just how many calories go “in” and how many calories go “out.” Unless you are a fully registered and certified geek, you may want to just skip ahead:

“Neither heat [i.e. what is measured by calories] nor work is separately a state function [i.e. quantities that depend only on the state of the system] because each is dependent on the path followed by a system in changing from one state to another . . . If [the First Law of Thermodynamics] is to be obeyed, heat must also be path dependent. It is therefore meaningless to refer to the heat or work content of a system (in the same way that it is meaningless to refer to the number of one dollar bills and ten dollar bills in a bank account containing $85.00).”

This is why when someone talks about a person storing “800 calories of energy as fat,” I hear something that makes about as much sense to me as saying a person can store “$85 dollars worth of money in his bank account as four twenties and a fiver.”

Calories are otherwise never mentioned again in the rest of the 1,310 pages of this book.


Biochemistry (6th edition), 2009

Mary Campbell & Shawn Farrell

Campbell y Farrell is my warm fuzzy teddy-bear of a biochem book. I LUV it. Cuddle up with C&F for a well-written, easy-to-understand (as these things go) romp through the wonders of biochem.

–“Calorie” is not indexed.

–“Caloric restriction” is indexed to a discussion of longevity and sirtuins, not weight loss or obesity.

Lehninger’s Principles of Biochemistry (4th Edition), 2005

David L. Nelson & Michael M. Cox

This is my favorite biochemistry book ever. If it were available and I were single, I would marry it in a hot second.

–“Calorie” is not indexed. Nor is “kilocalorie.” Nor anything else that I could think of having to do with “calories.”

There you have it.   Seems to me that all those broscientists want to talk about is something that doesn’t have a lot to do with the keys to the universe of nutrition.  I don’t mind talking biochemistry, but the basic biochemistry that I’m familiar with has virtually nothing to say about calories.

And if biochemistry isn’t too concerned with calories, why should you be?



The Magic of Calories

There have been a couple of interesting conversations on the interwebz involving calories lately. I don’t normally pay attention to these things because I am so busy napping being, well, busy, but I am paying attention to these conversations because they are both starring–ME!!!

Let’s face it, the whole “only calories matter, period” vs. “calories, shmalories” debate tends to be an oversimplification on both sides. But, the truth is, only one of these sides has been the primary focus of many decades of unsuccessful public health nutrition intervention. In that regard, the “all you have to do to lose weight is make sure your calories out exceed your calories in” stance deserves to be questioned.

To this end, Adam Kosloff has gathered a useful compendium of calories in-calories out naysayers (including yours truly):

Then, a different Adam, does some naysaying about the naysayers:

While it would be fun to naysay all the naysaying about the naysayers, rather I will just address the part starring ME!!!

In reference to my scientific-y calorie calculations about how long it would take me to “disappear altogether,” Adam the Second had this to say:

“Yes, If she were to drop her calories in by 500 a day and increase her calories out by 500, she would lose a shit load of weight after 6 months.”

Um, no I wouldn’t. I would lose about 30 pounds, then I would begin to regain. Because that’s what happened to me in my real life. Oh wait, but it probably didn’t happen to me in real life because I was a fat person then, and everybody knows that fat people lie about how much they really eat, and because everyone knows that scientific-y calculations are more real than anybody’s actual life.

Adam the Second:

“She just has to remember that metabolism will vary over that time span, so her calories will also have to. This is due to the body naturally requiring less calories [sic] as a smaller vessel, and also the body will lower non exercise energy expenditure (general fidgeting, moving around etc).”

WHAT? My metabolism is going to change over time because I’ve changed my eating patterns? That’s in direct contradiction to the whole “calories in, calories out” premise. There are no differentiated calorie labels that say “This low-fat yogurt contains 250 calories for those of you who haven’t been on a diet for 6 months, BUT it contains 5,680 calories for those of you who have.”

Yes, in more sophisticated venues, calorie calculators for “energy out” change with weight, but the overall premise stays the same and leads to the same conclusion.

So if I weigh 205 pounds, walking at a moderate pace for an hour burns 307 calories. Once I diet & exercise down to 180 pounds, I can burn only 270 pounds doing that same amount of exercise. Which means that now I have to eat EVEN less and move EVEN more to continue to lose weight (regardless of how little I was eating or how much I was moving in order to get to 180 pounds in the first place)? When does the madness stop???

Lucky for you, dear reader, I will now demonstrate, due to the magic of calories, that the whole “eat less, move more” ad infinitum ad nauseum ad starvatium ad exhaustium does stop and in fact–this is the magic part–even reverses itself.   All for the low low price of free.

Let’s take this whole calorie calculation/deficit/mumbo jumbo out for a “brisk pace” walk, shall we? One of the reasons I think that some folks are such diehard supporters of calories in-calories out, it that they’ve never actually been a fat person trying to navigate the terrain of the whole calorie-counting experience.  So let’s hold hands & try it together.

Let’s say I’m a big fat newbie. Let’s say I’m a 35-year-old, 5’10” OBESE female who weighs 240 pounds (not my current age or weight, but that’s approximately where I started in my own weight loss journey). I already know that I need to “eat less and move more” in order to lose weight, because that’s what my doctor told me. I go to a trusted source, the Mayo Clinic, for guidance (for those of you who want to play along at home, here’s the Mayo Clinic calculator).

First I need to know how many calories I actually require (so I can reduce them). I start off with a estimated energy requirement for my activity level, which I will calculate as “inactive” (“never or rarely include physical activity in your day”), because we all know that the reason that fat people are fat in the first place is because they are lazy slugs.

My calorie needs as calculated by the Mayo Clinic, by way of the Harris Benedict Equation and the Dietary Reference Intakes, are: 1850 calories/day.

The Mayo Clinic says: “Weight loss comes down to burning more calories than you take in. You can do that by reducing extra calories from food and beverages, and increasing calories burned through physical activity.”  They don’t provide any details about how to do this, but by consulting with the Academy of Nutrition and Dietetics, I find that “A negative energy balance is the most important factor affecting weight loss amount and rate” and that I can achieve this negative energy balance by decreasing my energy intake by about 500 calories/day or increasing my activity by about 500 calories/day–or doing both. Since “adipose tissue, which is mostly fat, contains about 3500 kcals/pound,” if I create a negative energy balance of 1000 calories/day, I’m 7000 calories down–or 2 pounds worth of fat–over the course of a week.

So here goes. I’m going to subtract 500 calories from my Mayo calculation (close your eyes, it’s a mathy part) in order to figure out that I should be eating: 1350 calories/day.

Okay, let’s say I add 500 calories of activity to my day. Using the handy-dandy chart below (also from the Mayo Clinic), I find have to walk for 1 hour and 45 minutes in order to burn 533 calories.

I am now at a caloric deficit of (at least) 1000 calories/day, which according to the super-duper magical 3500 calories = 1 pound of fat formula (Zoe Harcome explores the rigorous scientifically-proven assumptions behind the formula here) means I lose about 2 pounds a week. Not that this would always happen in real life, but okay, fine. Flash forward 5 months, I’m down 40 pounds. I now weigh 200 pounds.  At 200 pounds I am no longer OBESE, I’m just OVERWEIGHT, but I still have more weight to lose. Because my body is naturally going to “require less calories [sic]” because it is a “smaller vessel,” it is time to recalculate my energy needs.  To the Mayo Clinic calculator, Boy Wonder!

(What happened in my own real life when I dieted and exercised my way from 215 pounds to about 185 is that, not only did my weight loss stall, but I started to regain lost weight. Or at least, that’s what would have been happening to me if I hadn’t been lying about it to myself and my hunger and exhaustion weren’t complete figments of my feeble imagination, while in reality I stuffed my face with HoHos and laid around on the couch watching The Young and the Restless).

According to the “smaller vessel” theory, I should require fewer calories, but if I fill out the calculator–WTF??– I end up with more?

I weigh 40 pounds less, and I get to eat 200 more calories/day? I don’t get it, but the Mayo Clinic is a trusted source and I’m just a newbie, so on we go. I subtract my 500 calories/day so I can lose weight, now I am eating:  1550 calories/day

Okay, 1550 calories/day is not a lot, but it’s more than 1350 calories/day I was eating before.* I’m not sure why this is, but I’ll take it, because–even though I am a “smaller vessel”–clearly there must be some calorie magic at work. But while I may be able to eat (a little) more, on the other hand, now I have to exercise even more because my ability to burn calories has decreased (see chart below). Now I have to walk for 2 full hours each day in order to get my 500 calories out.

Following the magic 3500 calories calculation that exists in our magical perfect world, we can flash forward another 5 months. I now weigh 160 pounds, my goal weight. I am now no longer OBESE or even OVERWEIGHT, but thankfully, NORMAL.

But, being NORMAL, I am also now an even smaller “smaller vessel,” and because “the body will lower non exercise energy expenditure (general fidgeting, moving around etc),” it’s time to recalculate. This is really scary because if I could only eat 1850 calories/day as an inactive OBESE 240-pounder, will I even be allowed to eat at all now that I weigh 160 pounds?  Will I have to exercise half the day away in order to be able to “afford” the calories in a low-fat bran muffin?

Oh, I can hardly stand the–wait! Hmmm. Now hold on just a hot second here.

I can see by the calculator that at 160 pounds, I could be inactive and eat 1800 calories/day.


Because I’ve been eating 1550 calories a day and walking for 2 hours every day, and I am FREAKIN TIRED AND HUNGRY and sick of spending 14 hours a week walking around and getting nowhere.

According to the magic of “calories in, calories out,” I can now eat (even) MORE and move (a lot) LESS and I will NOT gain weight. No matter what I eat–as long as I consume no more than 1800 calories/day, I can sit on my (now slender) ass all day long and never gain an ounce.


P.S. If you are by any chance wondering why an OBESE inactive female who weighs 240 pounds is only supposed to be eating 50 calories more a day (a 7.7 calorie/pound allotment) than a NORMAL weight inactive female who weighs 80 pounds less (an 11.3 calorie/pound allotment), that’s because NORMAL weight people are more honest and virtuous than OBESE people and therefore deserve more calories per pound body weight.

P.P.S. Dear Adam the Second should you happen by to read this. Not trying to pick a fight. Just trying to illustrate how the calories in-calories out principle–put to work in a real-life example–may be an overly simplistic (if not downright illogical) approach to weight loss for some folks. Hey, if it works for you & your buddies, great! But it doesn’t work for everyone, and the use of this paradigm as the foundation for public health nutrition practice has changed how we think about eating in ways that I would argue have done more harm than good.

P.P. P.S. For more snarkily outraged, or outrageously snarky, commentary on calories, try these calorie-free nuggets of wiseassedness:

Why Calories Count Fo’Shizzle

Calories in, calories out, Would You Please Go Now?

Calories? Again? Already?

*This is where calories in-calories out folks sometimes like to say “But you may have needed more calories.  If you cut your calories too much [whatever that means], you’ll crash your metabolism.” I don’t know. They may be right. But that’s not how the calories paradigm works. There are no “metabolism crashing” exceptions on the Mayo Clinic calculator.