4 ms·

A thermodynamic explanation doesn't explain everything as well as a lot of folks act like. The same thermodynamic laws apply to growing a tumor rather than grow

A thermodynamic explanation doesn't explain everything as well as a lot of folks act like. The same thermodynamic laws apply to growing a tumor rather than growing a great fat mass. Our way of assessing food's caloric values are also imprecise. We act like all carbs and protein are 4kcal/g and all fat is 9kcal/g, but there is clearly some level of variation, some of it due to food and some due to individual. And of course we don't know for most ingredients how much of each macro and how much water they _actually_ have, we just use mostly-ancient reference values. All of that said, when we accurately track the amount of food people are eating, their weight does pretty predictably move with the calories in almost all circumstances. A lot of folks think they had other experiences, but people are really, really bad at accurately tracking their food intake. Shockingly bad, even when they're clearly trying. Similarly, when we measure people's oxygen usage, it tracks fairly predictably with weight changes, suggesting that we don't see outsized changes in 'metabolism' defeating folks. That still doesn't answer the question of why this is all happening.

diordiderot 5y ago
There was a BBC documentary where a woman self reports eating 1000cal and tests reveal she'd eaten over 3000. https://m.youtube.com/watch?v=KA9AdlhB18o https://m.youtube.com/watch?v=KA9AdlhB18o
tsimionescu 5y ago
> All of that said, when we accurately track the amount of food people are eating, their weight does pretty predictably move with the calories in almost all circumstances. This is only true in the short term - days,weeks. What is observed in the long term is that people, even the overweight and obese, reach stable weights without changing their lifestyle. So, if I were to start eating a surplus of 1000Cal/day compared to my current diet, and without changing my lifestyle in any other way, i would gain weight quickly until reaching some other significantly higher weight level, and then plateau there until I change other aspects of my lifestyle. This may be due in part to simple energy calculations (I need more energy to move around a higher mass), but is likely also affected by other metabolic factors as well (e.g. I would also develop stronger muscles to hold my bigger weight, and stronger muscles directly need more calories to be maintained). It's also extremely important, when discussing practical weight loss, to remember that appetite is also directly controlled by your body chemistry, and may vary wildly between people, probably explaining a huge amount of the observed weight differences.
inglor_cz 5y ago
Saying that humans (or other animals, because this problem is not unique to humans) gain weight because they consume more calories than they burn is like saying that planes crash because the force of gravity became stronger than the lift generated by the wings. An obvious physical truism, but it gets you nowhere on the field of disaster. And if you do not dig further into the problem (pilot error? machine malfunction? controlled flight into terrain?), you won't be able to prevent future disasters. For starters, short of outright starvation (0 is certainly 0), we do not even know how many calories we eat, and we might never be able to find out. The values written on the packaging are measured by burning said food in calorimeters, but our bodies aren't calorimeters and there is a huge systemic error, perhaps 30 per cent. Even chewing the food longer can increase the total calorie intake from the same meal. Personally, I had reasonable and sustainable results with intermittent fasting. Blood pressure normalized, waistline diminished, though not to the point of having a sixpack. But I didn't have the same sustainable results with generic calorie restriction and 5 meals a day. I was miserable, cold and felt hungry all the time. That is not life. None of those bad effects seem to be present on IF.

diordiderot 5y ago

There was a BBC documentary where a woman self reports eating 1000cal and tests reveal she'd eaten over 3000. https://m.youtube.com/watch?v=KA9AdlhB18o https://m.youtube.com/watch?v=KA9AdlhB18o

tsimionescu 5y ago

> All of that said, when we accurately track the amount of food people are eating, their weight does pretty predictably move with the calories in almost all circumstances. This is only true in the short term - days,weeks. What is observed in the long term is that people, even the overweight and obese, reach stable weights without changing their lifestyle. So, if I were to start eating a surplus of 1000Cal/day compared to my current diet, and without changing my lifestyle in any other way, i would gain weight quickly until reaching some other significantly higher weight level, and then plateau there until I change other aspects of my lifestyle. This may be due in part to simple energy calculations (I need more energy to move around a higher mass), but is likely also affected by other metabolic factors as well (e.g. I would also develop stronger muscles to hold my bigger weight, and stronger muscles directly need more calories to be maintained). It's also extremely important, when discussing practical weight loss, to remember that appetite is also directly controlled by your body chemistry, and may vary wildly between people, probably explaining a huge amount of the observed weight differences.

inglor_cz 5y ago

Saying that humans (or other animals, because this problem is not unique to humans) gain weight because they consume more calories than they burn is like saying that planes crash because the force of gravity became stronger than the lift generated by the wings. An obvious physical truism, but it gets you nowhere on the field of disaster. And if you do not dig further into the problem (pilot error? machine malfunction? controlled flight into terrain?), you won't be able to prevent future disasters. For starters, short of outright starvation (0 is certainly 0), we do not even know how many calories we eat, and we might never be able to find out. The values written on the packaging are measured by burning said food in calorimeters, but our bodies aren't calorimeters and there is a huge systemic error, perhaps 30 per cent. Even chewing the food longer can increase the total calorie intake from the same meal. Personally, I had reasonable and sustainable results with intermittent fasting. Blood pressure normalized, waistline diminished, though not to the point of having a sixpack. But I didn't have the same sustainable results with generic calorie restriction and 5 meals a day. I was miserable, cold and felt hungry all the time. That is not life. None of those bad effects seem to be present on IF.