Obese kids are more likely to become obese adults. An obese 4-year-old has a 20 percent chance of becoming an obese adult, and an obese teenager has up to an 80 percent chance of becoming an obese adult.
Source: Prevention of Pediatric Overweight and Obesity.” American Academy of Pediatrics, Committee on Nutrition, Pediatrics, August 2003. http://aappolicy.aappublications.org/cgi/content/full/pediatrics;112/2/424.