First lady loosens up food rules: 'Have pie! Eat the dressing!'

First Lady Michelle Obama encouraged American families to enjoy their food over the holiday weekend and not to worry about "how much you eat."

Obama, who is spearheading a nationwide campaign against childhood obesity, explained to 20/20 host Barbara Walters that "this is the time" to let go a bit.

"I would urge people to use this time to come together, as families and community, and don't take it for granted. Be kind to each other and laugh a little bit. And don't worry about how much you eat. Just enjoy it," she said.

She later added, "Have pie! Eat the dressing!" when prompted to explain her comment.

The wide-ranging interview also included a discussion of Obama's campaign, dubbed "Let's Move," which focuses on healthy eating among schoolchildren.

"You know, our goal is ambitious but simple," Obama said. "We want to end the epidemic in a generation. We're really aiming at children born today, because our goal is that if we begin shaping habits and shaping the conversation and providing information to parents and teachers and engaging all of our leaders in this conversation, that we'll change the habits of young people today."

The First Lady has faced criticism from Republicans, including former Alaska Gov. Sarah Palin, for advocating what they characterize as government overreach.

"A government has a role to play in this issue, as does every other sector," Obama rebutted in the interview. "And we reached out and engaged the grocery store manufacturers and the restaurateurs. We brought in the mayors and governors of states and towns. We're calling on faith-based community. There is no constituency that should be excluded from this call to action for our kids."

Both Obama and President Obama commented in another portion of the discussion that they both exercise to relieve stress.

The interview aired Friday.