The number of severely obese Americans grew by 75 percent between 2000 and 2005, according to a study by a U.S. research organization. Somewhat surprisingly, the number of moderately obese individuals increased by just 24 percent.

Individuals are classified as severely overweight or obese if they are more than 100 pounds overweight or have a body mass index of 40 or greater. A body mass index over 30 is considered to be obese. Researchers at RAND Corporation found that the number of Americans with BMIs over 50 increased the most, while there was a 50 percent increase in the number of individuals with BMIs over 40.

Economists at RAND fear that obesity trends have been underestimated in the past and are concerned about what these figures mean in terms of health costs. The number of weight loss surgeries has increased dramatically over the past decade – only 13,000 bariatric procedures were performed in 1998, but that number swelled to 200,000 in 2006, according to the study. Alarmingly, the dramatic increase in surgeries has done nothing to slow the obesity rate.

RAND researchers noted in a media statement that “the latest findings challenge a common belief held by physicians that people who are obese are a fixed proportion of the population and are not affected by changes in eating and physical activity patterns in the general population.” The health costs associated with obesity are putting a strain on an already fragile health system. The amount of information available about the increasing rate of obesity and the health risks associated with being excessively overweight is staggering. Which begs the questions – why has it taken so long for this issue to enter the media spotlight and why isn’t more being done to stop the epidemic?