It's not about nutrition

t's Not About the Broccoli is a really important book which offers a few important and feasible rules for parents of picky eaters. The first is to institute schedules: specific hours for breakfast, snack, lunch, snack, dinner, bedtime snack. If he doesn't want to eat at these times, he has to wait until the next block. For example, Breakfast is 6-7:30; Snack 10-10:30; Lunch 12-2; Snack 4-4:30 (veggies and dip available before dinner if hungry); Dinner 6-7:30, includes dessert if good effort made. 

For every meal, parents should offer one food he likes, and  one or two new foods. The BACKUP plan should be one safe food, like plain yogurt. The rotation rule is in effect too so you never have same foods two days in a row

Tasting is required. He must try at least one new taste every day. It can be a small bite and he can spit it out if he wants but he must give a yay or nay. Assure him there are no consequences (you won't make him eat whatever he says he likes.) Another idea is to start a chart: each new taste gets a star. 10 stars gets a new toy.