(AP) -- A food pyramid just for the under-2 set? Contrary to popular belief, children don't usually outgrow their baby fat - and a new report urges steps to help prevent babies, toddlers and preschoolers from getting too pudgy too soon.
That's a growing problem: Already, one in five preschoolers - 2- to 5-year-olds - is overweight or obese.
Topping the list of proposed changes: better guidelines to help parents and caregivers know just how much toddlers should eat as they move from baby food to bigger-kid fare. And making sure preschoolers get at least 15 minutes of physical activity for every hour they spend in child care.
Thursday's recommendations, from the Institute of Medicine, aren't about putting the very young on diets. But those early pounds can lead to lasting bad effects on their health as children grow, says the report.
"It's a huge opportunity to instill good habits at a time when you don't have to change old ones," said Leann Birch, director of Pennsylvania State University's Center for Childhood Obesity Research, who chaired the IOM panel.
Consider: Babies drink milk until they're full and then turn away. But children as young as 2 or 3 are sensitive to portion size, important in not inadvertently training them to overeat.
"If you give them larger portions, they eat more," Birch explained.
Pediatricians generally give pretty explicit directions on how to feed babies. And the nation's dietary guidelines include a special section for preschoolers, including information that a portion size generally is about 1 tablespoon of each food type per year of age.
But overall, those national guidelines are aimed at ages 2 and older - though surveys show even very young children eat too few of the fruits and vegetables they need. So the institute called on the government to create consumer-friendly dietary guidelines for birth to age 2.
That would capture the "dramatic dietary transition that occurs, from consuming one single food to, by the time they're 2, ordering up things from McDonald's and, we hope, having also learned to eat a lot of healthy foods," Birch said.
That will be part of the discussion during the next dietary guidelines update in 2015, said Robert Post, deputy director of the Agriculture Department's Center for Nutrition Policy and Promotion, which oversees that process. But developing guidelines for these younger children is complex because their nutrition needs are based in part on developmental stage, he cautioned.
Of course, parents have the biggest influence over whether healthy eating and being active become a child's norm.
But the report makes the case that children's habits are influenced by far more than their parents - and thus it's time to expand obesity prevention to more of the other places youngsters spend time. For example, nearly three-fourths of children ages 2 to 5 spend at least part of their day in some form of child care.
Among the recommendations:
-Day care and preschool operators should be trained in proper physical activity for young children, provide at least 15 minutes of it per hour, and avoid withholding physical activity as a punishment.
-Child care regulations should limit how long toddlers and preschoolers sit or stand still to no more than 30 minutes at a time - and limit holding babies in swings, bouncy seats or other equipment while they're awake.
-Day care and preschools should practice what's called responsive feeding: providing age-appropriate portion sizes, teaching children to serve themselves properly, requiring adults to sit with and eat the same foods as the children and following babies' cues as to when they've had enough.
-Breastfed infants are less likely to become obese later in childhood, so doctors and hospitals should encourage breastfeeding and limit formula samples aimed at new moms.
-At checkups, doctors should consider the parents' weight in assessing which children are at risk of later obesity, and then alert parents early that preventive steps are needed. About 10 percent of infants and toddlers already weigh too much for their length.
-To increase healthful eating among the poorest children, the government should take steps to get more families who are eligible for federal nutrition-assistance programs to sign up.
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