Don't know if this will work or not, but I had a 4 year old who wanted me to "feed" her all the time. I finally told her that if you wanted to act like a baby, you got the whole package: no "big kid" treats like candy, back to the crib, naps every day, and I would blend up her food like babyfood. Diapers might also be an option. (While it was a bit of an empty threat--we only have 1 crib after all!--I planned on actually implementing some of it if necessary, starting with blending up her dinner and taking away other big kid privileges.) For her, though, the discussion was enough. She understood that big kids had a lot of privileges that went along with having to feed yourself and she chose the privileges. Just make sure you don't phrase it like a threat. Just say, oh great, it would be fun to have another baby in the house. It might not be fun for you to be a baby though. This is what babies have to do, and what they can't do.... Are you sure that's what you want?
As noted though, my daughter was 4 and way past being fed. Your son is quite a bit younger. Part of his regression, as was mentioned by others, is probably because he sees the attention the baby gets, etc. So, factor that in, as well as factoring in how much he understands. This method may work better for an older child. This poor youngster's not even 2 yet. :)
Good luck!