IGF1 and Insulin resistance: A narrative review published in 2008 supported the role of physical exercise and energy restriction in the treatment process of cancer, demonstrating that some key biological mechanisms were providing important metabolic links between nutrition, physical activity, and cancer, including insulin resistance and reduced glucose tolerance, increased activation of the growth hormone/IGF-I axis, alterations in sex-steroid synthesis and/or bioavailability, and low-grade chronic inflammation through the effects of adipokines and cytokines [64].