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by tsimionescu 533 days ago
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.
1 comments
ch4s3 533 days ago
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/

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tsimionescu 532 days ago
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.

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