While trying to get in shape, Katie Holmes has had a fair share of ups and downs, but finally, she has accomplished her goal.

Recently, she probably had one of the biggest challenges of her life: training for the New York City Marathon. “She was determined to realize her lifelong dream of completing the race,” says a source close to Katie.

And that she did. Katie ran the more-than-26-mile course in under 5½ hours. “I’ve always loved to run,” says Katie, who at age 12 started doing three-mile loops around her hometown of Toledo, Ohio, with her siblings and dad.

Those who saw her finish the race were stunned how energized the 5-foot-9 Holmes looked when she crossed the finish line. “She didn’t even seem tired. She has a runner’s body now: lean and mean. Nothing jiggles!� says one witness.

Katie Holmes’s weight loss and diet While running probably had helped Katie lose some weight, following a healthy diet is the way to see real results. Katie’s diet plan focused on good carbohydrates, lean protein and good fats (think omega-3 fatty acids.)

If you goal is to lose weight, as a very general rule of thumb, consume around 1,500 calories a day coupled with at least 30 minutes or walking or jugging three times a week. If you are Katie’s size and training to run a marathon, consume around 2,000 calories a day and do not skip meals, ever. [source: Life & Style]