My 3-year-old son used to eat whatever we had for dinner, but somewhere along the line that got derailed. He's at a stage in his development right now where he doesn't have any concept of time, so threatening to take something away later just doesn't work. We're not really that worried about it because he never complains about being hungry and he almost never gets junk food or fast food. There have been many nights where he sits at the table without touching his food, and then a couple hours later he eats a bowl of cantaloupe or an apple or a PB&J sandwich, an hour before bedtime.
I mean sure maybe he'd start to understand if we didn't let him have anything later, but it's not like we can make him hungry when it's convenient for us. I'm fine with putting off the whole thing until he understands what's going on. I'm not sure what route we'll go then. I mean, we make awesome food so I'm tempted to go the "eat what we eat or eat nothing at all" route, but on the other hand they say that forcing kids to eat what they don't want makes it much more unlikely they'll eat it later. I do think it's highly likely that what works for one family doesn't necessarily work for us all. We eat dessert often, so I like the idea of offering them an alternative but then they get no dessert. I think that will be especially effective for two or more kids.