Why the calorie is broken

Why the calorie is broken

Interesting article about how we determine how many calories are in food and how many calories we can extract from food.

Differences in height, body fat, liver size, levels of the stress hormone cortisol, and other factors influence the energy required to maintain the body’s basic functions. Between two people of the same sex, weight and age, this number may differ by up to 600 calories a day – over a quarter of the recommended intake for a moderately active woman.

Other evidence suggests that gut microbes might affect weight gain in humans as they do in lab animals. Take the case of the woman who gained more than 40 lbs after receiving a transplant of gut microbes from her overweight teenage daughter. The transplant successfully treated the mother’s intestinal infection of Clostridium difficile, which had resisted antibiotics. But, as of the study’s publication last year, she hadn’t been able to shed the excess weight through diet or exercise. The only aspect of her physiology that had changed was her gut microbes.


I can’t find that study from the article. I did find this one, that said that the gut microbes in mice had an impact on how lean the mice were. It also said that a healthy diet (in this study, low saturated fats/lots of fruits and vegetable) changed the composition of gut bacteria to the ones that promote leanness. Interesting that gut microbes can have that much of an impact on body composition. What I I take away from this is that it’s going to be harder to lose weight on an unhealthy diet - so your calorie count may be influenced by where those calories are coming from.

Fascinating stuff isn’t it?

I have had the vague impression for a few years that we don’t actually understand the specifics of food and its interaction with health and behaviour particularly well. So much to learn.

Most of the way they present the math is just to make a shock statement.

No, calories are not perfect, but they are not “broken” either. They are a useful estimate.


I think the point was that they are only a useful estimate if your assumptions about how many calories you are eating and how many calories you are burning are close to the mark. If they are not then your estimate will not be very useful.

But if you listen to the podcast at the very end they conclude that until the science advances, calories are still the best way manage food/weight…

So the question is what composition of gut bacteria Soylent is creating…


I think a pretty good one. Mine are very friendly when they talk to me now.


I think the key here is that the starting estimate is just that - an estimate. Our understanding of what that means is broken.

If you estimate that your maintenance calorie level is 2000 kcal a day, and you eat about 2000 kcal a day, and you’re still gaining weight, then your estimates are off… so you lower your estimate of your maintenance level. Or maybe your estimate that you were only eating 2400 kcal a day was off, and you were really eating 2600 kcal - so you lower the amount you eat (or improve the accuracy there.)

Either way, the calorie wasn’t broken. We’re just forgetting that our calorie counts in all areas - basal maintenance calories, eaten calories, calories burned in activities - these are all estimates. Our estimates are often wrong at the start, but we should simply revise them, not abandon them.

It think part of the problem is that we’re so used to punching exact numbers into calculators and getting exact results immediately. We take starting estimates and immediately try to calculate exact outcomes! People want to believe that if they’re on a plan that shows a numerical deficit of 117 calories per day, they’ll lose a pound of fat per month*… while forgetting that the 117 is the difference between two much larger numbers (maybe 1950 calories in and 2067 calories out), and BOTH of those larger numbers are actually rough estimates that need to be refined over time based on your specific body and circumstances.

If those estimates are actually pretty good - let’s say, plus or minus 10% of reality - then the variance on the intake is plus or minus 200 kcal (a difference range of 400 kcal), and the variance on the calorie output is plus or minus 200 kcal (again, 400 kcal range), yet we somehow want to believe that the daily deficit between them of 117 is going to be exact!

  • PS: I don’t believe in the theory that a 117 kcal per day deficit leads to a loss of a pound a month, for a variety of reasons. But people really want to believe they can just boil things down to simple numbers which tell them they’ll hit a particular goal at a particular time.

I think the real problem is that most people don’t understand what food calories really are. It’s a measure of the chemical potential energy in the food, not the amount of energy your body can gain from it. It should be treated as a maximum value, not an absolute. The exception would be restaurant calorie counts, which should be treated as entirely meaningless numbers since there’s so much variation, as the article pointed out.

BMR is also problematic; calculations done based on weight, height, and activity level are almost never accurate. You need to participate in one of the human calorimeter studies described by the article to get an accurate BMR value for an individual.

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I will tell you this. Before I drank soylent, I was blessed with odorless farts. I could fart anywhere with impunity. The only time my farts would smell was during/after a vacation where I was eating different foods. After a few days, everything was back to normal.

Now my farts stink. All of them, not just the soylent farts. I think that’s a possible indicator that my gut bacteria makeup have changed as a result of my soylent diet.


Whoa. Differences in height, body fat, liver size, and other factors influence the amount of required energy. Those are disruptive findings that prove the whole system we live in to be completely broken, whatever it means. What I’ve been doing all my life is completely wrong. I didn’t know that height, body fat, liver size, and other factors could possibly influence the amount of energy required by my body. And, at this point, I’m wondering whether lean mass also influences the value. Thank God I read this article.

PS: thank you for wasting a few minutes of my life. I want them back.

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