Many obesity studies substantially underestimate the mortality risks associated with excess weight in the United States, new research indicates. Normal weight is indicated by a BMI of 18.5-24.9 kg/m2, overweight is indicated by a BMI of 25.0-29.9 kg/m2, obese class 1 is a BMI of 30.0-34.9 kg/m2 and obese class 2 is a BMI of 35.0 kg/m2 and above. Skeptics of the meta-analysis argue that the findings are likely driven by biases, especially by illness-induced weight loss.