The former First Lady has long advocated for Americans to live active lives. In the picture, the 55-year-old 'Becoming' author can be seen doing a lunge with an exercise ball. In a caption along with the photo, she shared the hashtag #SelfCareSunday. She also wrote that working out doesn't always feel great, but is glad to have done it. Michelle Obama, via Instagram During her time in the White House, Obama championed healthy eating habits for children. She also led the "Let’s Move!” campaign to take on childhood obesity.