In order to stop Sims from bloating like balloons, I not only visit gyms and spas often to keep NPC Sims exercising, I have created these clubs:
1 club for teens that go to Random Gym. You have to be Active or Lazy to be a member. The idea is that it is a club for teens that want to get fit, and needs some motivation.
2. Same, but for adults. I still have the default gym club in the game as well, but changed it too to "random gym" so they appear more often.
3. A spa club with the same parameters for elders (so they don't die working out).
MCCC will auto-fill and keep track of members. So basically I auto-force all lazy sims to work out often (muahahahaha!)
