I'm not sure metabolism or losing weight works in sims anything like real life! lol
And I don't think jogging does much for their physique at all, but I don't have my sims do much of it so can't say for certain on that point.
But I had a female sim who took after her much heavier father than her skinny mother, and she didn't have much luck losing weight or slimming down as a young adult.
Of course she was busy having five children, so I'll give her a break having to get rid of all that 'baby' weight.
But her perseverance paid off with working out to the radio when she was an adult, and she kept the weight off for quite some time, even into her elder years.
In fact, she outlived her husband, who was athletic and working out all the time, living to be 135 days old, when my lifespan is set to normal with a total of 100 days!