Michelle Obama: Sasha and Malia Not on Facebook

Updated at 9:55 a.m. ET

First Daughters Sasha and Malia Obama aren't on Facebook, First Lady Michelle Obama said on NBC's "Today" Show.

"I think we're lucky that there are a lot of real constraints, things like Secret Service and stuff like that," Mrs. Obama said. "I'm not a big fan of young kids having Facebook. It's not something they need, it's not necessary right now."

She added that she may allow Malia, 12, and Sasha, 9, to join the social networking site after leaving the White House, depending on how old they are at that time. In the meantime, she said she and President Obama are working to give the girls a normal childhood.

"If you talk to our kids, they're really very normal," she said.

"There are a lot of great kids who have come out of the White House," Mrs. Obama added. "The Bush girls are magnificent. Chelsea Clinton, she's a solid young woman... Caroline Kennedy -- we've got a pretty good track record. The Obama girls will hopefully be in that group."

Part of parenting is maintaining balance in children's lives, Mrs. Obama said -- a message she has tried to get across in her Let's Move campaign, a national initiative to promote healthy eating and living habits.

"I've always talked about balance in this campaign," she said. "If you go at a parent and say you can never take your kid to get a burger, you've lost them because that's not the reality we live in. That's not my reality."

"The changes we have to make in our lives are not wholescale changes," she added. "Many of the changes for kids are small things like adding fruits and vegetables and getting our kids moving."

The nation spends $147 billion a year to treat obesity related conditions, she said on "Live with Regis and Kelly" on ABC this morning, and the amount spent treating obesity in children is increasing.

"I came to this issue as a mom," she said. Parents, she added, "need to the tools, advice and support from a nation" to raise healthier kids.

The first lady is appearing on several television programs today to promote the one-year anniversary of the Let's Move campaign.