>> pelley: a health study says obesity is killing three times as many people around the world as malnutritioon. seth doane tells us about a missouri high school fighting the problem. >> hi, brandy, how are you? >> reporter: spend a minute in the nurse's office at truman high school in independence, missouri, and you'll immediately notice something troubling. what problems are you seeing? >> we see type two diabetes, high blood pressure. people with joint pains, arthritis, stre swrierkt depression. from being above a healthy weight >> reporter: school nurse lori halsey tells us 40% of students at truman high were overweight or obese. two years ago, he was part of a district-wide program to test students' body fat. >> you worry where they are going to be in the future.