First lady Michelle Obama flexes her muscles as she exercises with schoolchildren at the River Terrace School April 21, 2010 in Washington, DC. Mrs. Obama visited the school to highlight physical activity as a critical element of the 'Let�s Move!' initiative with several Olympians and Paralympians, including 2010 Olympians Shani Davis and Hannah Kearney and 2010 Paralympians Alana Nichols and Heath Calhoun. (Photo by Win McNamee/Getty Images)

First lady Michelle Obama’s “Let’s Move” initiative turns 4 years old this month, and by any measure it’s been a resounding success.

While critics cried “nanny state” when Mrs. Obama first proposed her campaign to focus on youth obesity, the program has undoubtedly raised awareness about a critical problem and affected our nation’s nutritional standards.

Thanks to the first lady’s efforts, our country’s school lunch program has been reformed and several major corporations have pledged to put more of an emphasis on fruits and veggies in their store chains.

Mrs. Obama has also practiced what she preaches, remaining physically fit and active at the age of 50.

Check out our slideshow of the first lady showing off her fitness moves and inspiring the nation’s young people to make healthy choices.