Read this Atlantic article at lunch today:
So, most of the time when I have read something about calories it’s more about what kind of calories - like how proteins are absorbed slower than carbs, so eat more protein if you want to lose weight, etc.
This article rather discusses how that metric - calorie - is used on food. About the inaccuracies in how it’s applied, let alone assuming people preparing food do it accurately (like those under 500 calorie meals at restaurants - an extra scoop of sauce or a generous cook with the sides can ruin that for the eater without them knowing).
The authors also talk about differing absorption rates for food, as well as how people absorb food differently. Like, cooking meat well done makes it easier for bodies to digest it, so you’ll actually get fewer calories out of a medium-rare steak than a well-done one.
The key point being, to me, that while none of the things they talk about are hugely impactful, they can add up to failure for people trying to lose weight —
“All of these factors introduce a disturbingly large margin of error for an individual who is trying, like Nash, Haelle, and millions of others, to count calories. The discrepancies between the number on the label and the calories that are actually available in our food, combined with individual variations in how we metabolize that food, can add up to much more than the 200 calories a day that nutritionists often advise cutting in order to lose weight. Nash and Haelle can do everything right and still not lose weight.”
The article is a good read, I recommend it.