Fitness (attribute)

In The Sims, a Sim's body type was fixed, and wouldn't change no matter how much he/she worked out or ate. The Sims 2 changed that by introducing a fitness scale which appears on the Simology panel. Sims in The Sims 3 also have a fitness scale, but it is not shown in the interface and a Sim's body shape changes gradually.

Sims can become fatter by continuing to eat after their Hunger bar is full, or become thinner by doing most things that increase the Body skill. If they gain or lose enough fitness, their body shape will change. Sims can increase fitness by swimming or working out on a community lot, even if they are not gaining Body skill.

Children can gain fitness by playing on swings, or jumping on the bed, though those activities don't seem to build Body skill. (This may depend on which expansion packs are insta lled.)

Workouts

In The Sims 3, there are 2 workouts. Cardio and strength. Cardio is going for a jog, using the treadmill or choosing the "cardio workout" option on a stereo or tv. Strength is pumping iron and choosing the "strength training" option on a stereo or tv. Cardio is proven to reduce the fat on a sim's body more than strength workouts because they focus more on build muscle than losing weight.

Lifetime Happiness The Body Sculptor can be bought op the lifetime rewards panel and a sim can choose if he/she wants to become fat or slim and muscular.