I'm having that problem, too, that the muscle gain is excessive. Any exercise seems to build muscle now, where as before it was cardio vs strength. I thought maybe with the new punching bags that if would be treadmill odor cardio/weight loss, weights for muscle, and boxing to maybe change both. My sim had a baby and then kept the baby weight, so started going to the gym. She didn't work out before, so the first visit or two didn't do much. Then when she seemed to be back pretty much to her normal size, she would maintain it by going for a quick jog. Now that quick jog is making her buff. She also does random exercise, like the push ups etc, too, so not sure if that makes a difference.
The funny thing is, the townies weight doesn't seem to change, not like in the last game.
