My son is the same age and I'm lucky if he'll eat that much in a week!! Like mamapoppins, he wants to feed himself, with a fork and spoon and that's it! He used to be interested in what was on my plate, but not much anymore... he's happy to eat (or play with) what's on his plate.
Somedays he'll eat 1/2 an apple, a few sips of soy milk and 3 bites of an avocado and that's it!! He's 20lbs 4oz., but I'm not worried - other days he'll eat like he's storing up for hibernation, and he's still breastfeeding a lot.
Also, he doesn't want to sit in his highchair anymore, either. So I let him sit at the table next to me. He can barely see over the top, but whatever works, right??
Does your son have his own plate, cup and spoon? These things helped us - gave him his independence.
The problem with Gerber Graduates and stuff like that is that it's so processed and refined it's not like real food anymore. It's probably very bland compared to what you're eating, so your food doesn't taste good to him. Just my humble opinion, of course. I would try just leaving stuff on his plate for him to have fun eating himself... brown rice, grapes, chickpeas, green peas, cherry tomatoes, etc. - stuff that LaLa suggested.
Also, the dipping thing - DS LOVES to dip stuff now. I do watered down refried beans, soups thickened with rice flakes, avocado with salsa, hummus and pureed carrots, tofu and garlic.
I don't know what it is about bread, but most kids this age love it! Try making your own pizza with carrot sauce and shredded cheese. DS would eat this all day if I let him!