Cancer Risk and Body Weight

According to a recent report, a third of cancers may be caused by poor diet and lack of exercise and could be prevented. It urges people to keep weight down and abstain from too much fast food, red and preserved meat, salt and alcohol.

The report from the World Cancer Research Fund is the most comprehensive overview of the role that food, drink, obesity and inactivity play in causing cancer. It concludes that changes in our lifestyle play as big a role as stop smoking in reducing the risk for cancer.

What is most striking about this report is not the suggestion of links between lifestyle and certain cancers, but the overwhelming strength of the relationships. Excess body weight was shown to be one of the main predictors of several types of cancers such as endometrial, esophageal, pancreatic, bowel, post-menopausal breast, and kidney cancers.

Therefore, it is of little surprise that at the top of the report's recommendations is that people should keep their weight down throughout their life. That might be good advice for individuals who have been able to maintain a lower body weight, but it can be daunting for the 2/3rds of Canadian's who are considered overweight or obese.

A common misconception is that the excess weight itself is the unhealthy culprit. Although the actual fat mass does have some health implications, we must not lose focus that it is the poor diet and lack of activity that excess weight typically represents that is the greater health problem.

Since it is still not clear if it is the excess weight or the lifestyle that lead to weight gain that increases cancer risk, we should be cautious not to focus solely on weight and body fat alone. Keep in mind that many studies have shown that even modest amounts of weight loss through improved diet and physical activity have tremendous health improving effects.

The World Cancer Research Fund recommendations are as follows:

1. Be as lean as possible without becoming underweight. Maintain a healthy weight through a balanced diet and regular physical activity to help keep your risk lower.
2. Be physically active for at least 30 minutes every day. Keep in mind that any type of activity counts.
3. Avoid sugary drinks. Limit consumption of energy-dense foods (particularly processed foods high in added sugar, low in fiber, or high in fat) Try to eat lower energy-dense foods such as vegetables, fruits and whole grains instead. Opt for water or unsweetened tea or coffee in place of sugary drinks.
4. Eat more of a variety of vegetables, fruits, whole grains, and legumes.
5. Limit consumption of red meats (such as beef, pork and lamb) and avoid processed meats. Aim to limit intake of red meat to less than 500g cooked weight (about 700-750g raw weight) a week. Try to avoid processed meats such as bacon, ham, salami, corned beef and some sausages.
6. If consumed at all, limit alcoholic drinks to 2 for men and 1 for women a day. Any alcohol consumption can increase your risk of cancer, though there is some evidence to suggest that small amounts of alcohol can help protect against heart disease. Therefore, if you choose to drink, do so in moderation.
7. Limit consumption of salty foods and food processed with salt (sodium). Try to use herbs and spices to flavour your food and remember that processed foods, including bread and breakfast cereals, can contain large amounts of salt.
8. Don't use supplements to protect against cancer. Research shows that high-dose nutrient supplements can affect our risk of cancer, so it's best to opt for a balanced diet without supplements.

The full report is available at http://www.dietandcancerreport.org

Drew Harvey is the founder and director of Healthy Weights
He is a kinesiology professor and has helped thousands at his research and weight loss clinic.
http://www.healthyweights.ca