A 2005 study in America showed that overweight people actually had a lower death rate than normal weight people as defined by BMI.[17]
In an analysis of 40 studies involving 250,000 people, patients with coronary artery disease with normal BMIs were at higher risk of death from cardiovascular disease than people whose BMIs put them in the "overweight" range (BMI 2529.9).[18] In the intermediate range of BMI (2529.9), BMI failed to discriminate between bodyfat percentage and lean mass. The study concluded that "the accuracy of BMI in diagnosing obesity is limited, particularly for individuals in the intermediate BMI ranges, in men and in the elderly... These results may help to explain the unexpected better survival in overweight/mild obese patients."[19] Patients who were underweight (BMI <20) or severely obese (BMI ≥35) did, however, show an increased risk of death from cardiovascular disease.
A study by Romero-Corral et al., using data representing noninstitutionalized civilians in the United States, found that BMI-defined obesity was present in 19.1% of men and 24.7% of women, but that obesity as measured by bodyfat percentage was present in 43.9% of men and 52.3% of women.[22]