KEY IDEA: America’s expanding waistlines are causing health spending to spiral out of control. Obesity-related illnesses consume nearly a third of the nation’s health-care dollars An obese adult uses 42 percent more health care than a healthy-weight adult, and a morbidly obese adult uses a staggering 81 percent more, according to the Robert Wood Johnson Foundation. Until we start fighting this epidemic, the nations’ healthcare costs are going to continue to climb.