"One of our goals was to focus on the importance of educating our kids about healthy eating," said Obama. "So it wasn't just about planting a garden.
The event was attended by about 100 children and some parents from local elementary schools. Among the presenters were chefs Koren Grieveson, Todd Gray, and dietician Ellie Krieger, who hosts the show "Healthy Appetites" on the Food Network.
"So many children in this nation are facing health problems that are entirely preventable," said Obama. "We've got our kids who are struggling with things that we have the power to control."
Concerned with higher rates of blood pressure, heart disease, and cancer, Obama warned of dire consequences in the coming years.
"We're headed for the next generation being on track to have a shorter life span than us."
As a solution, Obama urged children and parents to refrain from junk foods and desserts as regular sources of food.
"My mother would tell us, 'dessert is not a right. It's a treat.' So we had it on special occasions," she said.
As a mother of two girls, she has often heard this: "I don't wanna eat it. I don't like it. It tastes bad. I don't want it," the first lady said in a childish imitation.
"We don't want to hear the whining. We want you to eat it. Just eat it."
Alongside healthy dishes like sweet and zesty popcorn and zucchini quesadillas, Obama joined the children in exercises. She performed 142 revolutions with a hula hoop, the Associated Press reports, before it hit the ground. Her double dutch skills, however, were not as strong.
The first lady said that the White House event is part of a nationwide program, the Healthier U.S. School Challenge, which encourages schools to serve healthy meals, and reduce junk food.
"Changing old habits is never easy," Obama said. "If your school commits to this challenge, there's a possibility that I'll come and check it out."