Childhood obesity is growing at an alarming rate, but experts say parents are more powerful than they imagine at helping kids fight the problem.

Three studies presented at this week's Pediatric Academic Societies' annual meeting, in San Francisco, offer ways to help kids get to healthier weights.

Mothers in families where food is sometimes scarce due to money problems have a tendency to give their children high-calorie foods to boost overall calories or foods to stimulate the appetite -- two practices they should avoid if they want their child to remain at a healthy weight, said Emily Feinberg, an assistant professor of maternal and child health at Boston University School of Public Health and an assistant professor of pediatrics at Boston Medical Center.

In her study, Feinberg interviewed 248 mothers of normal and overweight black and Haitian children, aged 2 to 12.

She found that 28 percent of them had shortages of food from time to time. When that happened, 43 percent used nutritional drinks such as high-calorie instant breakfast drinks, and 12 percent used substances to stimulate appetite, such as traditional Haitian teas, in a well-meaning effort to be sure the children got adequate nutrition. Instead, Feinberg said, these low-income mothers should "try in general not to focus as much on calories but on the quality of the diet. Instead of a nutritional drink supplement, we would recommend increasing the intake of fruits and vegetables."

Helping your child have good self-esteem can also motivate him or her to lose weight, found Kiti Freier, a pediatric psychologist at Loma Linda University in Loma Linda, Calif., and director of the Growing Fit Program there.

When she interviewed 118 overweight children participating in a 12-week program, she found that good self-image was even more important than how much excess weight they carried in predicting whether they were ready to lose excess weight.

"Their readiness to change relates to whether they felt supported, not how big they were," she said. The message for parents of chubby children is clear: Don't point out how much overweight they are. Instead, try something like this: "We love you so much. We want you to be healthy and have a long life," Freier said. Then offer them a plan and support.

Other parents may have the mistaken belief that a child is not overweight, when he or she actually is. Dr. Elena Fuentes-Afflick, an associate professor of pediatrics at the University of California, San Francisco, tracked the attitudes of Latina mothers with preschool-age children on their kids' weight. She analyzed data from interviews with 194 women and children taking part in the Latino Health Project. The women were recruited during pregnancy and then interviewed annually for three years.

By the time they were three years old, more than 43 percent of the children were statistically overweight. But, "in the group of kids overweight by our measure, three-quarters of those mothers thought their child's weight was just fine," Fuentes-Afflick said.

"We are living in a society where two-thirds of adults in the U.S. are overweight or obese," said Fuentes-Afflick. "What concerns me is the risk that we are normalizing overweight body images."

The studies provide valuable information for researchers and parents, according to Connie Diekman, a registered dietitian and director of university nutrition at Washington University in St. Louis, Mo. The first study on scarce food, "provides some support to why the prevalence [of overweight ] is higher" in poorer populations, she said.

The study relating a child's self-esteem to their readiness to lose weight also makes sense, Diekman said. "Self-esteem is a major factor in the establishment of healthy behaviors and [a lack of it] can contribute to overeating and eating disorders."

Finally, the last study confirms the key role mothers play in determining what a child eats and weighs, Diekman said.