Healthnotes Newswire (May 15, 2008)—Everyone knows that being overweight can lead to a variety of serious medical conditions including heart disease, diabetes, and high blood pressure. New evidence now shows a link between body mass and several cancers, giving yet another reason to trim those extra pounds.

Body mass index (BMI) is a formula based on height and weight that clinicians use to determine body fat and health risk. Body mass index equals a person’s weight in kilograms divided by their height in meters squared. A normal BMI is considered to be 18.5 to 24.9 kg/m2, overweight is 25 to 29.9 kg/m2, and obese is 30 kg/m2 or greater.

This study looked specifically at the risk for cancer with a 5 kg/m2 increase in BMI, which, in people with a BMI of 23, is the equivalent of about a 15 kg weight gain in men and 13 kg in women.

In men, a 5 kg/m2 BMI increase was strongly associated with esophageal, thyroid, colon, and renal cancer. In women, a 5 kg/m2 BMI increase was associated with endometrial (uterine), gallbladder, esophageal, and renal cancer.

Weaker increases in risk were indicated for rectal cancer and melanoma in men; postmenopausal breast, pancreatic, thyroid, and colon cancer in women; and leukemia, multiple myeloma, and non-Hodgkin lymphoma in both sexes. Findings were similar in studies from North America, Europe, Australia and Asia.

“In US adults, 71% of men and 62% of women are overweight or obese (with a BMI of more than 25 kg/m2); in the UK, 65% of men and 56% of women are overweight or obese,” said Andrew Renehan, PhD and his colleagues from the School of Cancer Studies, University of Manchester, UK. “Moreover, these prevalences are expected to increase, in the UK, for example, to 75% of men and 58% of women by 2010. Excess bodyweight could therefore contribute to a substantially large burden of cancer in such populations.”

Tips to achieve a healthy body weight

• Eat a healthy diet abundant in fruits and vegetables and low in saturated fat and added sugar.

• Exercise daily! Adults should have at least 60 minutes of a combination of moderate and vigorous physical activity each day.

• Remember that calories taken in must be burned off in order to lose weight and/or maintain a healthy weight. So a healthy weight depends on the right balance of healthy eating and exercise.

• If you are overweight and having difficulty trimming down, see a doctor and nutritionist who can help you lose weight and keep it off.

• Sometimes medical conditions, such as hypothyroidism, can contribute to weight gain. If overweight and having difficulty losing weight see a doctor.

(Lancet 2008;371:569–76)