Jessica Simpson loses weight after giving birth to son Ace through walks and the energy of her children

Courtesy: Weight Watchers

“With both kids I’m running up and down my stairs a million times,” Simpson told USA Today. “Kids can keep your metabolism going.”

But that’s not all. The 33-year-old singer, who has two children with her fiancé Eric Johnson, takes long rides with the father of her children.

“Eric and I go on walks together,” the fashion mogul said. “I try and walk about four miles a day consistently. It makes me feel better.”

After her second pregnancy, Simpson restarted the Weight Watchers diet. The mom-of-two has lost more than 50 pounds after her first pregnancy, so it seems the diet is working for her.