Comment by nelgaard

Yes, those marathon runners mentioned might reduce their TEE from 6200 to 4900 kcal/day. But that is still way more than most office workers eat.

And if you check the article:

https://www.science.org/doi/10.1126/sciadv.aaw0341# == The reduction in TEE among RAUSA subjects can be partly attributed to marginally reduced body mass and daily mileage (table S3). Still, even after accounting for these changes, Week 20 TEE was 596 kcal/day lower (range, 400 to 923 kcal/day) than expected ==

So they did loose weight during the marathons and the metabolic compensation is less than half of what you would think reading the original article.

== ... The magnitude of metabolic response in RAUSA athletes (~600 kcal/day, ~20% TEE) is similar to the degree of adaptation reconstructed for the most physically active subjects in a recent cross-sectional study (17) and may reflect humans’ maximal capacity for metabolic compensation. ==

So if 20% percent is the maximum, it means that if you try to outrun your diet, you might have to eventually exercise 25% more. Except by then you will probably have more muscle mass that will burn more calories even when not exercising. And you will be able to exercise more in less time.

Suddenly it does not look so hopeless.