I am the mom of a 8yr old boy and a 2 1/2 yr old girl and a 8 month old baby girl, So I know a thing or two about tantrums!
My boy, about that same age did the same thing. I remember we were at my in-laws and he was about 9 or 10 months, he started to get smart when he would throw his head back, it was kinda funny in the middle of crying he would stop, look back, move to the carpet, then proceed with throwing his head back.
This is my theory, there are different stages were they are able to do things and they think they can or should be able to do it their self,(such as 2,4,16)but we know that they can't.
What I do, because I hate to say no all day! Is try to offer something else he could have. They just want to be like us and have what we have, maybe when eating put some of his food on your plate and pretend to eat it to make him want it
Just remember, he still a baby, he is just discovering his world and learning to communicate, at the same time you are learning what make him tick, only you are the expert on your son. Have fun!!