Michelle Obama: Healthy Eating 'Isn't Just About Looks, This is About Nutrition'

First lady Michelle Obama pushed back against criticism that she should not have brought up the example of her daughters in her remarks about childhood obesity.

"I understand the sensitivity around ... the entire conversation, particularly as a mother with girls," Obama said in an exclusive interview with ABC News. "I mean this conversation is not about just weight or size or BMI [body mass index]. It's about overall health and the kind of lives that we want our kids to lead. And we've got to set them up for success."

Obama touched a nerve when she made the issue of healthy eating personal last month at an event in Alexandria, Va., where she kicked off a campaign addressing the problem of childhood obesity.

VIDEO: The first lady discusses changes her family made to promote healthy eating.Play

The first lady said her pediatrician told her to look at her daughters' BMI and warned that "something was getting off balance."

"It's often hard to see changes in your own kids when you're living with them day in and day out," she said. "But we often simply don't realize that those kids are our kids, and our kids could be in danger of becoming obese. We always think that only happens to someone else's kid -- and I was in that position."

The first lady's comments stirred up the Web and medical world, drawing both criticism and praise. Some said Obama should not have personalized the issue and brought up her daughters. Even if it is for the greater public good, critics said, it does not bode well for her daughters' self-image. Others said the first lady used that example only to connect to Americans who may find themselves in a similar position.

VIDEO: The first lady talks about her nationwide campaign called, "Lets Move."Play

Obama told "Good Morning America's" Robin Roberts that "we have to be very careful" when talking about young girls, and she emphasized that parents need to address the issue and "have a full conversation."

Click here to read more about Michelle Obama's plan to battle childhood obesity.

She again gave the example of her daughters to reiterate her own experiences in dealing with the issue, and as an example of how doctors and parents can work together.

"That was something I experienced. My pediatrician kind of waved a flag very early on in our -- in our girls growing up. And it

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Michelle Obama's Battle Plan for Fighting Childhood Obesity

was sort of like you might want to look out. But then what do you do?" Obama said. "And that's where we need to make sure that parents have the next steps that they can take if a problem is identified."

The first lady stressed the importance of balanced eating and how it helped her turn the situation around in her own household.

"We want to make sure that people understand this is about overall health and physical fitness is ... something that I stress in my household. It is a part of that. It's a natural part of your life," she told Roberts. "My kids have to get up and move. They can't sit in front of the TV. I have my girls involved in sports because I want them, as young women, to understand what it feels like to compete and to win and to run and to sweat. ... This is about all of that, as well."

Behavior Change vs. Weight Change

When the first lady made her comments about her daughters in January, some said that Obama's comments could be perceived as too strong a focus on weight and dieting, which could send the wrong message to the public.

The first lady should be discussing behavioral change, not weight loss, said Laura Collins Lyster-Mensh, an eating disorder activist and executive director of Families Empowered and Supporting Treatment of Disorder (F.E.A.S.T.).

"We've confused health and weight in a way that's very confusing for children and very confusing for parents," Lyster-Mensh said. "When we speak publicly about putting our children on a diet, we start to get into weight stigma and confusing the message to families."

The focus on obesity, Lyster-Mensh said, turns this into an issue of appearances, which does not bode well for children, especially girls.

"There is simply no reason to be pushing children into weight reduction diets, and that's the message parents out there get," Lyster-Mensh said. "Dieting is a gateway drug to eating disorders for those with a biological predisposition to eating disorders."

Some said parents talking about their daughters' weight can have a harmful impact on young girls.

"One of the things I've noticed is that a lot of girls develop an eating disorder because they don't want criticism from their parents," said Jeanne Sager, a reporter who blogs on parenting Web site babble.com, and who herself, struggled with an eating disorder.

"I don't think Mrs. Obama was trying to do anything harmful to her children," said Sager. But talking so openly about her daughters "makes it more or less open season" for criticism on their weight, she said.

Doctors said behavioral changes are key to guiding children to a healthy life.

"Weight is just a marker for behavior. Losing a particular amount of weight does not work well for kids," said Dr. Goutham Rao, clinical director of the Center for Pediatric Weight Management and Wellness at the Children's Hospital of Pittsburgh, and author of "Child Obesity: A Parent's Guide to a Fit, Trim and Healthy Child."

He said that the first lady raised an important issue by pointing out how her pediatrician went about informing her. Talking about the BMI "opens the door for discussion," Rao said.

Rao said giving a personal example helps to convey the message better to others.

"I think it's completely appropriate she raised it and personalized it so that other mothers and fathers can relate to it," Rao said.

"The fact that she made this public, about her own ... modest changes she made was exactly that -- that this is a public conversation about what we're all doing," said Dr. Judith Palfrey, president of the American Academy of Pediatrics, who was present at the event last week. "It's like a neighborhood conversation except that it's national, about how we live."

Childhood obesity is a major issue facing the United States. It is a serious medical condition that affects close to one-third of all children in the country. That means one in three children in the United States is overweight or obese. Blacks have a 51 percent higher prevalence of obesity prevalence compared with whites, according to the Centers for Disease Control and Prevention. Hispanics have a 21 percent higher obesity prevalence compared with whites.

The first lady has made fighting childhood obesity one of her key priorities. She inaugurated the famous vegetable garden at the White House and has encouraged sports and other healthy activities among kids.

Experts say parents play a huge role in guiding their kids to a healthy lifestyle, which includes encouraging physical activity, eating healthy foods, and consuming less fast food. Obama agreed.

"You've got to have a full conversation," The first lady told Roberts. "The approaches to the problem have to work -- reflect that. ... Four pillars, where physical fitness is key. The quality of food in school lunch -- again, this isn't just about looks, this is about nutrition."