Another explanation is an increased level of insulin-like growth factor (IGF) which correlates with calorie intake in animals,16 height in children,17 and risk of colorectal and prostate cancer in adult humans.18 In support of the IGF-malignancy link, there is a positive relationship of stature with carcinoma of the prostate and colorectum in several studies. This evidence concerns the gene IGF1 and prostate cancer.