[tsimionescu]

Only assuming you have a steady body weight and diet, which is a very bad assumption for most overweight and obese people.

Not to mention, the processes in your body are way more complex than all this makes them out to be. For moderate exercise, after an adaptation period of a few weeks to months, there is almost no calorie impact from the exercise itself on your total calorie expenditure: your metabolism adjusts and various internal processes are deprioritized to prioritize the exercise.

This is in fact a major component of why exercise is so healthy: it doesn't do much for weight loss, but it stops/slows down all sorts of unnecessary processes in the body that are actively harming your overall health.

[ch4s3]

> almost no calorie impact from the exercise itself on your total calorie expenditure

This is categorically false. You don’t have a magical metabolic adjustment, you simply become more efficient in performing an exercise but the calorie use never drops to effectively zero like you’re claiming. Think about this for a second, it makes no sense to think that running could ever consume zero calories, basic physics still apply.

[tsimionescu]

I explained this very clearly. The exercise of course has to consume calories. But that doesn't mean they have to be calories in excess of your base metabolic rate. What happens is that your base metabolic rate decreases more or less commensurately with the amount of extra calories you're consuming through excercise. If your BMR was 2000 Cal/day when doing 0 calories from excercise per day, and then you start exercising for 300 Cal/day, your BMR will decrease to about 1700 Cal after some time of maintaining this routine.

[ch4s3]

You are completely wrong though. There's a large body of work dating back decades pointing to BMR increasing with exercise.

[1]https://pubmed.ncbi.nlm.nih.gov/2204100/

[2] https://pubmed.ncbi.nlm.nih.gov/8775359/

[tsimionescu]

And the newer work is starting to find the limits that I mentioned. There are several caveats that I didn't mention for brevity:

- no exercise vs moderate exercise vs athlete-level exercise are very different cases. Doing some exercise does increase total energy expenditure vs no exercise, but the amount doesn't change significantly until you get to pro-athlete levels. That is, going from 2000/0 Cal (BMR/exercise) to 200 Cal of exercise might take you to, say, 2100/200 Cal; but moving from 200 Cal of daily exercise to 400 Cal of daily exercise will not take you to a higher TEE; unless you reach the stage where you are doing, say, 1000+ Cal worth of daily exercise (specific numbers pulled from thin air, just trying to illustrate the concept).

- Muscle mass is a confounder for what I was claiming - more exercise leads to increased muscle mass normally, and that does lead to an increase in BMR very directly.

Overall the more correct claim I should have made would be "exercising more, assuming you are not very sedentary, will not lead to increases in total energy expenditure beyond those gained from muscle mass increase, unless you get to pro athlete levels of exercise".

Here are some studies backing me up:

- https://journals.physiology.org/doi/full/10.1152/physiol.000...

- https://onlinelibrary.wiley.com/doi/10.1002/ajhb.22711

- https://www.cell.com/fulltext/S0960-9822(15)01577-8

I'm taking all of these links from the Kurzgesagt sources for their video on exercise: https://sites.google.com/view/sources-workoutparadox. They link to more specific claims from each paper, and to a bunch of other papers.