Here are two picture books about picky eaters:
Gregory, the Terrible Eater by Mitchell Sharmat, illustrated by Jose Aruego and Ariane Dewey (Four Winds Press, 1980)
This one has been loved by children and families for nearly three decades and has been a Reading Rainbow selection. A very picky eater, Gregory the goat refuses the usual goat diet staples of shoes and tin cans in favor of fruits, vegetables, eggs, and orange juice.
"Just how much does Mom want Daisy to eat her peas? What is it worth to her? Well, she'll give Daisy a dish of ice cream and a new bike and a baby elephant and then she'll even sweeten the offer and buy Daisy her own chocolate factory. Will Daisy take the bribe and eat her peas? Or will she turn the tables on Mom? A familiar battle of wills escalates into a hilarious standoff in this bright, cheerful book, full of charming graphic illustrations. The characters and situation are familiar and funny... and anyone who has ever forced down one more brussel sprout in order to earn dessert will find the resolution true to life. Eat Your Peas is the perfect dinnertime companion!" (summary from Syndetics, Inc.)