Age: 46
Occupation: First Lady of the United States
Previous TIME 100 Appearances: 1
As First Lady, the Ivy Leagueeducated Obama has one of the biggest bully pulpits in the country, and she's chosen to use it to combat childhood obesity. Her Let's Move campaign works to promote exercise for sedentary kids, and she has courted controversy by calling on food manufacturers to provide healthier options at the grocery store.