This is a VERY common problem. When my DS went thru this 2 years ago, his DC gave me the best advice: it's our jobs to present them w/ healthy food, it's their option to eat or not, if you keep switching foods at meal time, or feed them something different than the family, then you'll be forced into the roll of a short-order cook, and they'll force you to continue in this roll as they get older!
Keep in mind thier stomachs are about the size of their fists and we usually give them more food than they really need. Seems like my 14 mo. DD ends up w/ more food on the floor and in her highchair than in her, but she's gained 3 lbs in the last 3 months, so I guess she's eating well!! But damn if it doesn't seem like she's a picky eater. I never know what will appeal to her. It seems like she will eat one good meal a day, and I've read that's all they really need.
There are several good cookbooks out there w/ suggestions on how to sneek foods into thier favs (like adding pureed carrotts to mac-n-cheese).
Kids often get on various food kicks, favoring one food or another for several days on end, which is ok, the experts say to look at what they are eating over a course of a week or so.
If you LO is gaining weight, peeing and pooing regularly then they are getting enough.
I've learned there are 3 things you can not make a child do: eat, sleep or use the potty, these are prime areas for battles!
The Dr. Sears website is: www.askdrsears.com