Do babies lose excess chub when they walk on their own??

My son is around 38lbs, and is pretty tall for his age. he's a big boned little boy and is learning to have confidence in walking. he can walk on his own, little steps, but still holding onto someone or something as he goes. Will he lose the chubby rolls around his upper legs and knees? He's a very active boy, I'm just concerned about him appearing so lol.