I Want to Save Your Life (2009)

Charles Stuart Platkin, also known as the Diet Detective, stages undercover health interventions. His mission is to coax Americans back to a more healthy lifestyle. "Do you want to see your daughter graduate from college?" he bluntly asks one target. Another woman is forced to walk 2.5 miles -- the distance she'd have to go to burn off the calories in the slice of chocolate cake he makes her carry as she walks. And no, she doesn't get to eat the cake after the walk. He works with each person to help them find out why they've developed the weight issues they struggle with, and then he helps them develop more effective ways to deal with their problems.