Massive hugs. I dont really know about behavioural problems like you describe, but have you have him tested for allergies or intolerances?

While we were in the USA I reacted to some seasoning on popcorn and later on chicken and my god, my heart was racing my brain was pumping, I was talking too fast and feeling like I could go mental. I just imagine if a child were reeacting to something, they would be aggressive, difficult and defiant. It might be worth looking at a book like nourishing traditions, or even the GAPs diet to see if you can affect change.

I would also hazard a guess he is behaving like this at home because you have a young baby and an older child taking your attention and he feels like he needs to act out to get attention, any attention. I would be inclined to start keeping him closer to help his security. Does he sleep in his own room? Is he difficult to get to sleep?

I would also start making him your special friend and really actively and positively involving him in every activity. So the cooking example, I would pick him up and put him on the bench to watch or find a way he could become involved.

When my kids are difficult I hold them closer. Stop what I am doing, slow down and try and connect with them more to hear what their needs are. That's just an ideal I aim for though. Yes I do crack it at times and yell, stomp and lock myself in my room

Good luck.