I dunno…in the US where well over 50% of the population is somewhere between overweight and obese, seems like many bodies are doing a pretty piss poor job of balancing the calorie intake/expenditure thing!
I agree about counting calories & fat grams & all that though…seems like awfully hard work when there’s sensible no-brainer things one could do instead. Like eating more fruit & veg. Exercise is way important to overall health too.
I sort of like lost weekday’s suggestion too.
Well that’s the tricky thing about weight. Even in the fattest of the fat, the neuroendocrine system has successfully matched energy intake to energy expenditure with an error of less than 1%. For most people the error is less than 0.5%. Compare that to the error on nutrition labels which is +/- 20% and would be even worse if you take errors in sizing portions together.
I don’t want to get bogged down in details, but the upshot is the cerebral cortex is not designed to calibrate the appropriate caloric intake, any more than it was designed to calculate your daily insulin levels. Yes, fat people will have to override their hypothalamus if they want to lose weight, but you’ll notice that’s an unsuccessful project for most of them long-term. Basically once that system’s broke you’ve got problems. And especially in someone who’s doing well I would not mess with it.
If you didn’t change your diet (assuming it’s not that great), but increase your calorie expenditure (say, by 3500 calories per week), would you lose weight or would your body adapt and you’d stay the same?
If you did increase your expenditure by 500 calories a day (that’s a lot of exercise by the way), you’d likely lose weight for a while. But after a certain amount of weight loss your hypothalamus would probably uptick your appetite and downtick your metabolism to try to drive you back to the fat mass you held before. I say probably because, while the physiological reaction to loss of fat mass is well established, it has generally been studied using caloric restriction (diets), not increased exercise alone, so I’m not going to insist it must work the same way if you’re losing fat mass solely by increasing your expenditure. Particularly in light of some evidence that people who are more successful at maintaining weight loss tend to exercise more.
But in general the assumption that metabolism and appetite/intake can be fixed, and fat mass will vary freely around those variables is mistaken. In general the body seems to try to hold fat mass fixed and will vary intake in particular (via appetitive controls) as well as metabolism to a degree (and likely even physical activity) to keep fat mass within a certain range (say +/- 10% of wherever it happens to be). It seems to be a bit more vigorous in preventing fat loss and bit more relaxed about fat gain, which is probably why people can override it a bit in the gain direction and not so much in the loss direction. This is a gross oversimplification, of course, but it’s a useful model to help you think about energy regulation in the body.
**Merkwurdigliebe ** seems to be a good example of someone in whom the this regulation is working quite well despite a sedentary lifestyle and an environment with access to a superabundance of calories. It sounds to me like what he’s describing is muscle atrophy, not so much weight gain, so he should be thinking more about getting fit again and less about calorie restriction, or even weight loss IMHO. The back of the envelope calculations of calorie requirements are necessary for people who want to maintain a long term large weight loss and are therefore forced to permanently override their internal controls by permanent dieting, but that’s not a good situation to be in and not something I’d recommend for someone who was not obese to begin with.
By the way, Mr. Blue Sky, if you’re asking if weight loss will cause your body to slow your metabolism alone enough to compensate for your increased expenditure, I’d say no. This seems to be limited to about -10 or 15% or so on average, so metabolism alone would not be enough to prevent weight loss if you’re exercising that much. But the appetitive controls are nothing to sneeze at and I’m guessing you will not be able to lose a large amount of weight this way permanently without also trying to override serious changes in your appetite by starting to diet. Simply put, when your body decides you’ve lost too much fat it does not stop nagging you until you’ve gained it back. But again, what weak evidence there is on the matter seem to indicate that the people who do best at maintaining weight loss are the ones who exercise the most - so I say go for it. Besides, exercise is very good for you whatever your weight. There’s plenty of evidence that people who are fit and fat are a better health risk than people who are thin and unfit.