Naruto : Might Tai
The fast and dirty synopsis is this - Tai used to be a rancher, now he is a punch wizard, with the emphasis on punch. Duy is 15 when Tai was born. Poor as shit and without the magnificent goatee. Tai wants some cows, he wants some horses, he wants to eat good steak. He is an old man in a young body and thoroughly decides it is everyone else's problem too.
The well articulated synopsis is this - A former rancher is reborn in Konoha as Might Tai, the older nonexistent brother of Might Guy and son of Might Duy. With no system and his only cheat the ability to help things grow stronger through food, Tai takes a different approach to survival in the Naruto world: build the body first. Better food, better animals, better training, better recovery. As he quietly transforms a poor household into something stronger, he will also be changing the fate of Konoha itself.