Percentage of the U.S. Population That Is Obese or Overweight Overweight - 19.2% (Body Mass Index of 25.0 to 29.9) Obese - 7.4% (Body Mass Index of 30.0 to 39.9) Extremely Obese - 4.2% (Body Mass Index of 40.0 +) Source: Society of Actuaries, "Obesity and its Relation to Mortality and Morbidity Costs." December 2010. (pdf)