Make an apt. with a child psychiatrist. These are not typical behaviors.
Look up "Oppositional Defiant Order" on Google.
Your child may have ADHD with coexisting Oppositional Defiant Order.
Not to panick you...I have an oppositional child, not to the degree you have, but the sooner you get help, the easier it will be.
One bit of advise - do not battle with your child. He probably likes confrontation and enjoys seeing you get all upset. As soon as you sense a fight starting, leave the room, don't engage him.
You are right , there are things going on and you need to speak to professionals.
Good luck.
I would definately discuss the excessive preoccupation with food (hyperphasia) with the developmental ped to rule out Prader-Willi Syndrome.
well i do know his focus and hyperactivity is always at therapy and at home, he is super hyper and not much focus on what we want him to do and he cant sit for a second, unless he is eating he will literally eat for an hour straight or more. But as far as the moods it's at home and not that he doesn't act out for others but usually lots of people give in to him so that's why he is happy with them, if i gave in all day i am sure i would be his best friend. The thing is he is jackle and hyde seriously, he can be defiant for me for reasons i don't understand like his real bad mood then a lightswitch when we show up at the school he is hugging everyone acting like nothing is bothering him. Heck it can take him a split second to change his mood, he is basically making a liar at of me in a whole. At doctors he gives me a dirty look for me telling him to stay in the room please instead of the hall, turns around, wont look at me, then doctor walks in and he is hugging me and them he will hug anyone he sees. Then when the doctor leaves the room he turns back around and wont look at me like he is still angry with me.
Also simple things he has progressed at therapy with even speech he won't do for me. I ask him "use your words when asking for something" He turns around wont look at me and stares off into space. He does this with everything i say to him unless i have food in my hand giving him or things on "his" terms this is what he gives me. Yet at therapy he asks for things he wants, doesnt give them a hard time that much. But i am not in the room during his therapy, the one therapist said he had a lollipop in his hand during speech that may be why he was complying (mispelled). He has Echolalia that i see he repeats everything i say or the last word in my sentence. But yet speech therapist is telling me all he "can" do as it has me baffled. 
Thanks everyone. He also is on the autism spectrum so explaining things to him isn't on his terms and he will just turn around, not make eye contact with me, and ignore me. This is the same child who craves attention that he get's from everyone.
I have an ABA therapist with him but he manipulates them, he knows how to win and get what he wants, we have been through lot's of therapists cause of that. I have ignored him but now he ignores me a lot just cause i ignore his behaviors. If i hug him and engage him it's back to him telling me "no" about everything i am trying to do with him play or whatever. He is also back to demanding food and then get's mad and goes back to ignoring and staring into space if i don't get it to him quick enough or i don't give him the 3rd piece of cake for instance. Thanks for advice he is 3 1/2, but has been doing this for a long time, years so i can't say it's a phase at this point. He does whatever they want him to do at therapy then is totally defiant at home and everything on his terms. He is very smart i love him so much and want to get him help. I probably will take him to a psychiatrist.
I don't have much advice, but I would like to point out that you say he turn the behaviors on and off. He acts one way for you, and the another for daycare etc.... The fact that he can pick and choose when he wants these behaviors says alot if you ask me. I don't think a lot of children with ADHD can turn them on and off. I wish you luck, keep us posted
i forgot too and needed to add, if i leave the room when he is doing something to try to annoy/upset me, he keeps doing it and walks in room for a split second to see what i am doing then leaves. But see when i get him angry for whatever reason he turns around and closes his eyes if you even come in his space. He needs to see everyone and everything that is going on and that may be part of why he is on his feet. He is easily distracted and needs to know what everyone is doing. He doesnt play with toys much just his strings and if he is doing something to annoy i move to another place and he will move right in front of me so i look at him. He also will bump into me and hug others when i have told him "no" about something like he is getting reinforced from them and thinks he is getting something out of it.
Anyway it's good if you got through all this post it was long, Thanks for suggestions. I love him and just want to help him and for us to have peace.