Cutting child off from food…? Wwyd?

My 6 year old eats a LOT. He will typically eat 2-3 servings of everything I have. Like if I make spaghetti, he will keep asking for more. If I cut up fruit, he will eat the entire bowl. Like he would probably eat a whole watermelon if I let him. I have taken him to the pediatrician about it because there are medical conditions that can cause uncontrollable appetite but he does not have any them. He’s also not always eating. He just wants massive portions for breakfast, lunch and dinner, and usually wants a snack before bed. But I’m worried that it’s just… too much? He’s only six and easily out eats me. I don’t know any adult that can eat three whole plates of spaghetti. My husband thinks we should just cut him off. Obviously obesity is a future concern. He doesn’t even say “I’m still hungry”, he just says “I want more.” Wwyd? This child is eating me out of house and home. I feel like I am cooking for 3 extra people.