Around 30 to 50% of obese subjects are metabolically normal (MNO) whereas numerous non obese subjects are metabolically abnormal. The distribution and the function of adipose depots seem to play a crucial role to explain this apparent discrepancy. The present article describes the clinical and biological characteristics of these metabolically healthy, but obese patients, analyzes the underlying pathophysiological mechanisms, assess the prognosis, especially regarding the cardiovascular risk, and finally discuss the advantages and disadvantages of a classical therapeutic strategy.