The overall rate of childhood obesity stands at 17 percent, or approximately 12.5 million obese children in America today (Doheny 1 ). The number of obese children is increasing at a rapid rate. Most cases of childhood obesity are caused by excessive eating and lack of exercise. Excess weight exposes children to serious health problems; such as diabetes, heart disease and asthma (Smith 1). Although obesity is preventable, it has become a growing problem among children due to several factors that lead to health problems. Obesity is defined as excess body fat. Body fat can be difficult to measure directly, which is why obesity is measured by the body mass index (BMI). The United States government states that each individual should consume between 1,500 and 1,800 calories and 50 to 60 grams of fat per day (Getting Started 1). Michael Phelps consumed 15,000 calories a day while training for the Olympics. The reason Phelps is not obese is that he exercises enough to burn off all the extra calories and fat he consumes daily. If a person consumes more calories than they burn, the result is weight gain. Exercise, food, technology and money all play a role in childhood obesity. Lack of exercise among adolescents has been shown to be the leading cause of childhood obesity. According to a May 2012 Institute of Medicine report, only half of American children and one in four adolescents get enough activity to meet current guidelines (Doheny and Noonman 1). Recommendations call for children to participate in at least 60 minutes of vigorous to moderate physical activity each day (Hendrick 1). “Only four percent of elementary schools, eight percent of middle schools, and two percent of high schools provide daily physical exams... middle of paper... related to childhood obesity.” Health. January 5, 2004. CBS News. April 8, 2014. “First things first: what is obesity? » lets move.gov. Let's move. April 7, 2014. Hendrick, Bill. “Survey shows children are not meeting recommendations for daily physical activity.” WedbMD: 1-2. “Many American children don't get enough exercise.” calsouthern.edu. April 13, 2011. University of Southern California. March 12, 2014. Noonman, Peggy. “Tips to make sure your child stays fit.” United States Today. September 2013: 1-2. “Weight problems and obesity in children”. Help your child achieve and maintain a healthy weight. February 2014. Help Guide. March 12 2014 .