I've been doing keto and am fairly athletic. I also am doing it because I find it hleps my moods and affect, and I have a stable weight when I am on this diet.

I don't think that you have to be calorie-restricted to benefit from a ketogeneic diet.

The climber Dave MacLeod has a 4-hour long video that seems (to my untrained eye) to have a number of good sources. He also has a masters degree in nutrition and is a professional athlete.

He describes how underfeeding was indeed a problem with his early experiments with this approach to diet, but how it's been quite effective after being careful to eat enough.

https://www.youtube.com/watch?v=L9dtfNZahKw&t=46s