A report issued by an international panel of experts says that the best way to significantly reduce the risk of getting cancer is to be lean, exercise vigorously every day, avoid fast food, eat less red meat, and avoid preserved meat such as ham and bacon, eat more plant-based foods and cut down on alcohol.

The panel said that diet and lack of exercise cause one third of all cancers which could be prevented by changes in lifestyle.

However, the overriding message from the detailed 537-page report titled “Food, Nutrition, Physical Activity, and the Prevention of Cancer”, issued by the World Cancer Research Fund, is the strong link between obesity and cancer risk.

Sir Michael Marmot, who is professor of epidemiology and public health at University College London, chaired the expert panel that reviewed 7,000 papers on the causes of cancer and consulted 200 experts worldwide. He said “the most striking thing to emerge from the report is the importance of overweight and obesity”.

Another panel member who chairs the International Obesity Task Force based in the UK, Dr W Philip T James, said the report had one message that was “as clear as a bell”. The link between cancer and obesity is “so robust, it is going to rank close to the smoking problem in America pretty soon”.

The panel comprised 21 internationally renowned experts in cancer, epidemiology, obesity, nutrition, and public health, backed by teams of observers.

However, the message does not stop with obesity. Every extra pound brings greater cancer risk says the report. Even if you are in the normal range of weight for your height, there is a significant difference between being in the lower weight region and being in the higher weight region.

In terms of BMI (Body Mass Index), the panel recommends people stay within 18.5 and 25, which is the lower part of the “healthy” zone.

BMI is a measure of obesity that divides the person’s weight in kilograms by the square of the height in metres. Thus a person who weighs 150 pounds (68 kilograms) and stand 5 feet 9 inches tall (1.8 metres) has a BMI of 22.1, which is in the lower half of the healthy zone, as recommended by the panel.

Too much body fat is a risk factor for oesophagal, pancreatic, endometrial, bowel, kidney and post-menopausal breast cancers said the report. And excess abdominal fat also increases risk of bowel cancer.

The panel concluded that people should stay lean throughout their lives, young people should avoid piling on the pounds and stay slim. One panel member said he was “shocked” when he realised this.

The report suggested a 10-point plan to reduce cancer risk (in addition to stopping smoking and chewing tobacco):

  1. Stay lean and slim. Keep to the lower range of normal body weight and don’t put on extra weight.

  2. Get 30 minutes of exercise a day. Build more activity into everyday life.

  3. Eat less energy-dense food such as fast foods, processed foods and sugary drinks. These are low in nutrients and high in fats and sugars. Even pure fruit juice has sugar.

  4. Eat a variety of vegetables, fruit, wholegrain cereals and pulse foods such as beans and lentils. These contain fibre and help to keep weight down. As well as 5 a day, try to eat them with every meal.

  5. Keep consumption of red meat (beef, lamb and pork) to less than 500g of cooked weight a week and avoid processed meats like bacon, ham and salami, corned beef and some types of sausage.

  6. Avoid or limit alcohol to one drink a day for women or two for men. Evidence shows any alcohol increases cancer risk but it may reduce risk of other diseases, so if you choose to drink it, do so in moderation.

  7. Limit consumption of salt and foods processed with salt. Use herbs and spices to add flavour and be aware that processed foods like bread and cereals usually contain added salt.

  8. Don’t take supplements to protect against cancer, although certain groups may need them (the report has more information on this).

  9. Breastfeed your baby if you can, exclusively for 6 months before giving any other food.

  10. Cancer survivors should also follow recommendations 1 to 8 after treatment.

Click here for the full World Cancer Research Fund report.

Written by: Catharine Paddock