Hmmm...might still be the molars? Maybe that is part of the reason for the big change? Many toddlers go on "hunger strikes"...and as frustrating as it is for Mom, the fact is that they won't starve themselves!
There is not much you can do....any amount of cajoling, bribing, or even talking about it can lead to a power struggle, and you sure don't want that! Keep offering...giving him one of his accepted foods at every meal, but adding a thing or two that you think he *might* eat. Bear in mind that it takes lots of exposure before a lo will try a new food. Also thibk about expanding into things that are similar to his accepted foods...like of he likes waffles, try french toast...(you can put it in the toaster after you cook it in the pan, this will make it crisp more like a waffle). Great if his yogurt is low in sugar and has added fruit...if it doesn't, I might switch to one that is super-healthy...you can make the switch gradually by mixing a bit of the new one into the old one. With the bread...try dips like hummus or peanut butter...sometimes making food more interacttive can be helpful...like letting him dip or spread things on bread with a popsicle stick!
Good luck hon....if he is drinking enough water, maybe taking a quality multi vitamin, and having milk...he will be ok....it really is just a phase....and it will pass.