We showed that serum afamin concentration was increased in individuals with prediabetes and newly diagnosed yet untreated T2D and that it positively correlated with many obesity and diabetes-related phenotypes e.g. body weight, BMI, waist circumference, % of body fat, subcutaneous and visceral adiposity, fasting glycemia, insulinemia, triglyceridemia, free fatty acids, atherogenic and insulin resistance (HOMA-IR) index and negatively with whole-body insulin sensitivity as assessed by EHC. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.