Our observations may explain the differences between results obtained from other studies, which investigated the associations between dietary carbohydrates and obesity or T2DM, while one of them suggested that low-carbohydrate diets may be a very effective treatment option for subjects with T2DM and obesity39, whereas another suggested that diets in which carbohydrates make up more than 50% of total daily energy intake may have a protective effect on glucose–insulin metabolism40. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.