Hundreds of obesity and cancer studies have shown that the risk of cancer increases with too much fat on the body--being overweight or obese.
Now a new review of 221 studies involving over 250,000 cases of cancer has confirmed the obesity and cancer relationship.
Researchers from the University of Manchester and the University of Bern performed a systematic review and meta-analysis of 20 different cancers and BMI (body mass index, a height/weight calculation).
Healthy BMIs are usually numbered between 18 and 25. Overweight is numbered at 25 to 30, obesity is numbered at greater than 30, and morbid obesity is numbered at greater than 40.
For example, a 5'7" person weighing less than 158 pounds has a BMI less than 25, within the normal BMI range. If that person weighs 190 pounds, their BMI is 30, a 5kg/m2 increase, putting them in the overweight classification.
The researchers found that for every 5kg/m2 increase in BMI, the rates of cancer increased as follows:
For men:
52% increase in esophageal adenocarcinoma cancer
33% increase in thyroid cancer
24% increase in colon cancer
24% increase in kidney cancer
For women:
59% increase in endometrial uterine cancer
59% increase in gallbladder cancer
51% increase in esophageal adenocarcinoma cancer
34% increase in kidney cancer.
Increased BMIs were also associated with up to 20% increases in rectal cancer and malignant melanoma in men, and pancreatic cancer, thyroid cancer, postmenopausal breast cancer, and colon cancer in women, with increased leukemia, non-Hodgkin lymphomas, and multiple myelomas for both men and women.
These results were similar for Europe, North America, Australia, and the Asia-Pacific regions (Renehan AG, Body-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studies, Lancet, February 2008).
Healthy people can manage their BMI and weight with appropriate calorie, nutrition, and exercise plans. For example, it is easy to substitute a cup of delicious green tea at 2 calories for a high calorie snack or dessert of 400 calories.
People with serious weight problems should consult with their health care providers for a complete weight management plan.