The first study in Germany examined 314 people aged 18 to 69. Researchers measured their total body fat, visceral fat lining internal organs, and subcutaneous fat found under the skin. The results found that obese individuals with insulin resistance had more fat in skeletal muscles and the liver than obese individuals who were insulin sensitive.
However, the obese insulin sensitive individuals had the same level of insulin sensitivity and artery wall thickness as the normal weight group. The researchers concluded that, "We provide evidence that a metabolically benign obesity can be identified and that it may protect from insulin resistance and atherosclerosis."
The second study, at the Albert Einstein College of Medicine, studied body weight and indices of cardiometabolic abnormality in 5,440 people who took part in the National Health and Nutritional Examination Surveys. The results revealed that 23.5% of people at normal weight were metabolically abnormal and, of the 51.3 percent of those that were overweight, a surprising 31.7 percent were metabolically healthy.
The researchers concluded that, "These data show a considerable proportion of overweight and obese US adults are metabolically healthy, whereas a considerable proportion of normal-weight adults express a clustering of cardiometabolic abnormalities."