And it is not even expensive to a full type 1 civilization on the Kardashev scale. We just need to hack some genes to not require exercise to develop muscle mass. We already can do it with drugs, and we probably could do it genetically if it wasn't for safety and ethical concerns. As for the cost, I expect a Type 1 civilization to be able to fix genetic diseases as a routine operation, and they could fix muscle atrophy at the same time, if desired.

Muscle mass requires more energy, but by definition, a Type 1 civilization has no shortage of it. And I expect making food out of thin air (like plants do) would be the kind of technology such a civilization would have.