Interestingly, monocytes are CNDP2+ cells (i.e., macrophages, immune and epithelial cells), where biosynthesis of N-lactoylphenylalanine (Lac-Phe) (from lactate and phenylalanine) occurs against a background of physical activity, which has the function of suppressing appetite and reducing obesity. This evidence concerns the gene CNDP2 and obesity due to melanocortin 4 receptor deficiency.