Although we found no direct correlation between leptin levels and sweet taste recognition thresholds in OW/Ob subjects, we did observe that the magnitudes of the diurnal variations of leptin and of the recognition thresholds for sweet compounds (sucrose, glucose, and saccharin) were significantly and negatively associated with the insulin resistance HOMA-IR values, calculated on the basis of fasting insulin and glucose levels. Here, LEP is linked to Insulin resistance.