You may remember your parents urging you to finish your dinner by encouraging you to be a member of the "clean plate club." The saying has been used for years as a way to get children to finish the food on their plates at mealtime.

But it''s a philosophy many dietitians now believe is not only outdated but could actually shape habits that lead to a lifetime of overeating.

"We have to be really careful with the clean plate club," said Dotti Durbin, a dietitian the Washington University Heart Care Institute at Barnes-Jewish Hospital. "I think that really sets a child up for learning to overeat or to bypass those innate abilities to know when we''re full."

Not finishing our food may seem like a waste. But in this age of supersizing, where even items on a restaurant''s children''s menu can seem like more than enough food for an adult, knowing the recommended portion sizes for the littlest among us is important.

"Children don''t need adult-sized portions," Durbin cautioned. "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."

"There''s a lot to remember," said Melissa Baum, a mother of daughters Emma, 3, and Ellie, 16 months. "It keeps going in your mind of what they should be eating, how much, and that''s sometimes difficult."

Baum says she faces a different worry with her children. She''s often concerned her daughters aren''t eating enough at mealtime. But both of her daughters like vegetables, which helps put her concerns in perspective.

So how much is enough when it comes to portion sizes for kids?

Durbin says there''s an easy rule of thumb for toddlers and preschoolers. "We''re looking at a benchmark of about a tablespoon of each food, served per year of age," she said.

Durbin said school-age children should really be selecting their own portions from a selection of nutritious foods at mealtime. By serving themselves, children learn how much to eat based on how hungry they feel.

"Both young children as well as school-age children will have differences in their appetite as their growth pattern changes," Durbin said.

Expect children to also experience what Durbin calls "eating jags," periods where they may or may not really like a particular food or may not like their foods touching on the plate.

"We really have to respect their learning process as they learn to enjoy foods," Durbin said, "and keep offering those foods that they''re not so fond of because they will become very fond of it."

Comforting advice for Baum, who, by instinct, has been following many of these rules.

Baum said her daughters "kind of tell me when they''re full and I listen to that more than anything."