my dog got neutered at 4 years old and how hes more agressive and wont stop eating! what do I do?

I got my pug neutered very late at 4 years old and the first couple weeks was fine, but now he is more aggressive and will not stop eating. He will steal our other pugs food, and freak out at her to get her food.

bring him to the vet he might need medication

Hypogonadism does have a side effect of increased depression and aggression, but the increased, almost driven, appetite is something different. Check his thyroid.

I'm sorry this has happened (and you'd not see any immediate change after castration in any case) but this just goes to show that the only certainty with castration is no puppies. I'm afraid any pre-castration behavioural problems he had will still be there, so now you have to get down to training this hooligan! And feed him in a completely other area/room so he can't get at your other dog's food!!Add - It might be worth speaking to your vet his increased aggression because it is possible to give him some hormone treatment to improve the balance in his system after castration. The removal of the testosterone should have made him calmer, but perhaps this hasn't been the case with him.