Better Homes and Gardens puts Michelle Obama on its cover

(CBS) Michelle Obama is no stranger to magazine covers, but her appearance on the cover of next month's Better Homes and Gardens is a rare milestone.

The magazine hasn't put a public figure on its cover in more than four decades (the last one was actor Cliff Robertson in 1963). She's also the first female public figure to make the cover.

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Inside the magazine, Mrs. Obama talked about her efforts to keep her own family healthy.

The first lady admitted that life in the White House took some getting used to. A visit to her daughters' pediatrician encouraged her to make changes to her family's diet, and she increased her time at the gym to make up for her more sedentary lifestyle, which she said has paid off.

"I always tease him I'm in better shape than he is," Mrs. Obama joked about her husband. "I can do long workouts. He's the president."

The magazine spread features photos of Mrs. Obama hosting a picnic with the fifth grade class from Harriet Tubman Elementary School, using vegetables from her White House garden.

The first lady, who has made fighting childhood obesity one of her personal causes, added in the interview that parents need to encourage healthy eating.

"Children's habits can be changed so much easier than adults," says the first lady, who has made fighting childhood obesity her personal cause. "They don't have control over their diets - we do."

The August 2011 issue of Better Homes and Gardens is on newsstands now.