Have you ever ordered a kid''s meal at a restaurant, only to find the portions are enough to feed more than one child? How much is enough when it comes to serving sizes for growing youngsters?

In this world of super-sized meals, even the kid menu can include a lot of food. But there''s one rule of thumb that can help you feed any child - from the pickiest eater to the one with an adult sized appetite.

At Development Child Care in the Dogtown neighborhood of St. Louis, vegetables and fruit are on the menu each day the children are allowed to serve themselves. Taking just as much as you want is considered good training for later in life.

"I''m very lucky," said Melissa Baum, mom to daughters Emma, 3, and Ellie, 1. "My kids eat all the vegetables that I give them ... (I''m) very lucky."

But Baum also worries her children may not be eating enough. In this age of an abundant supply of food, knowing how much is enough may sometimes be confusing.

"Children don''t need adult-sized portions," said Dotti Durbin, a dietitian with the Washington University Heart Care Institute. "In fact, adult-sized portions can really overwhelm a small child''s appetite and that can lead to a process of overeating and becoming overweight."

So here''s an easy breakdown of how much to feed children of different ages.

For school-aged children, dietitians suggest offering a variety of nutritious foods and let them serve themselves. Encourage children to take only as much per serving as they think they can eat.

For younger children, Durbin recommends this formula.

"When we think about a preschooler or toddler we''re looking at a benchmark of about a tablespoon of each food, served per year of age. That''s a good starting point."

But it isn''t a lot, especially considering the generous portions of food served on the kid''s menu at many restaurants.

Baum said she''s been following her instincts and allowing her kids to tell her when they''re full. She''s relieved to hear small portions are the rule for children her daughter''s age.

"I''m not going to worry as much now that I know that because I think she''s eating fine. That''s not very much food."

The Centers for Disease Control and American Dietetic Association offer information on serving sizes for children.