Insulin resistance is a condition of gluco-metabolic sufferance that may hesitate in the further development of type 2 diabetes and cardiovascular disease. The development of insulin resistance is mostly associated with the accumulation of excessive fat in the body. The epidemic impact of obesity in the youngest promoted an increase of the prevalence of insulin resistance also in children and adolescents. Increased fat accumulation in the peri-visceral area of the abdomen, occurring preferably at and after puberty, and in the liver, as non-alcoholic fatty liver disease, plays a role in the process. After puberty, males are at higher risk than females to develop insulin resistance. Also ethnicity contributes to sensitivity of children to develop insulin resistance, where Hispanics, South-Asians, and Indians are at higher risk than Whites and Blacks.In spite of the research progress in the field, several questions on the relationship between body composition and insulin resistance are still unanswered. Multiomics approach, combined with nutrition as well as imaging techniques might contribute to unravel the role of body composition on insulin resistance.