My current employer also has a policy allowing a certain amount of unpaid time out of the office for charity projects that you'd like to participate in.
Other cultures tackle it differently to. In Japan, organized stretching before work is commonplace.
https://www.youtube.com/watch?v=cqPW6H3soKA https://www.youtube.com/watch?v=biGPteoP2jg
However, it's very silly to compare procreation with fitness.
The fat procreator still benefits the society far more than the slim non...procreator, because on a 100 year or 200 year scale, both are dead, and the society only contains the progeny of one of them.
Put it this way: would you rather have a phone that can be upgraded a ton but will eventually wear out and stop working, or have a phone which can be endlessly replaced such that it is always modern and working, even if it isn't top of the line?
You can choose not to eat food, but the individual will not last long.
You can choose not to have kids but the society won't last long.
It's in our interest to support the human part of humanity. We do that with breaks, meal breaks, sick time, vacation time, and other things. But it's also in our interest to benefit society, not just the individual. So we incentivize choices which are mandatory to the health and success of our society, such as creating the next generation to replace those aging out of the workforce.