She also tried a little jump rope, The Washington Post reported.
Speaking to dozens of children and parents at a Healthy Kids Fair on the White House South Lawn, Obama noted one in three American children are overweight, a condition known to lead to serious health problems such as high blood pressure, heart disease and cancer in later years.
The situation is so dire, she said, "medical experts are now warning that for the first time in the history of this nation, we're headed for the next generation being on track to have a shorter life span than us."
While sounding that serious warning about the need to eat healthier and exercise more, Obama acknowledged in a light-hearted way how hard it can be to give up unhealthy foods, such has her favorite: french fries. She got laughs when she said: "I love them. Dearly. Deeply.:
"I have a good relationship with french fries and I would eat them every single day if I could. I really would," she said. "But I know that if I'm eating the right things -- and I tell my girls this -- if you're getting the right foods for most of the time, then when it's time to have cake and french fries on those special occasions, then you balance it out."
Obama and Agriculture Secretary Tom Vilsack also pushed his department's challenge to U.S. middle and high schools to serve healthier food and provide more time for exercise and physical activity.