The Working Group concluded that there is sufficient evidence in humans for the cancer-preventive effect of the absence of excess body fatness. The absence of excess body fatness reduces the risk of cancers of the colon and rectum, pancreas, gallbladder, oesophagus (adenocarcinoma), gastric cardia, liver (hepatocellular carcinoma), kidney (renal cell carcinoma), ovary, endometrium of the uterus, breast in postmenopausal women, and thyroid, and meningioma and multiple myeloma.
In addition, the absence of excess body fatness may reduce the risk of fatal cancer of the prostate, diffuse large B-cell lymphoma, and cancer of the breast in men.
Results of studies of cancer prevention in experimental animals concur with those in humans. There is sufficient evidence in experimental animals for a cancer-preventive effect of limitation of body-weight gain by dietary restriction, for cancers of the mammary gland, colon, liver, pancreas, skin, and pituitary gland. In addition, an association between limitation of body-weight gain by dietary restriction and reduced cancer occurrence was observed for cancer of the prostate and for lymphoma and leukaemia.
Several mechanisms linking excess body fatness with carcinogenesis were identified, including chronic inflammation and dysregulation of the metabolism of sex hormones.