Meat-eaters who switch to vegetarianism gain less weight over a five year period than people who make no changes to their dietary habits according to a new study published* today (13 March 2006).

Cancer Research UK scientists studied the eating habits of 22,000 meat eaters, fish eaters, vegetarians and vegans of all ages over five years and compared weight gains in all these categories.

On average people gained two kilos during the period studied but the lowest weight gain was seen in those who had changed to a diet containing fewer animal foods.

Among people who did not change their diet over the five-year period the largest weight gain was in meat eaters and the smallest weight gain in vegans.

The study, conducted in Oxford, is part of the European Prospective Investigation into Cancer and Nutrition (EPIC). It also found that men and women who changed their diet in the direction of meat to fish or fish to vegetarian or vegetarian to vegan showed less weight gain than those who made no dietary changes.

Professor Tim Key, deputy director of Cancer Research UK’;s epidemiology unit at Oxford University, who planned the study, said: “Contrary to current popular views that a diet low in carbohydrates and high in protein keeps weight down, we found that the lowest weight gain came in people with high intake of carbohydrate and low intake of protein.

“The data also showed that people who became more physically active during the five year period gained less weight than people who did very little exercise. This confirms that the best way to prevent obesity is to combine a healthy diet with exercise.”

Overall, researchers found that during the five-year period the proportion of overweight people increased from 29.4 per cent to 34.9 per cent in men and from 19.1 per cent to 24.2 per cent in women. The proportion of obese men increased from 4 per cent to 6.9 per cent and the number of obese women from 5.7 per cent to 8.4 per cent.

Professor John Toy, medical director of Cancer Research UK, said: “EPIC continues to highlight the importance of diet and exercise in achieving a healthy weight. We know that obesity contributes to increasing the risk of cancer as it does to heart disease and diabetes.

“This study suggests that a healthy weight is easier to maintain by switching from meat to eating fish or a vegetarian diet.”

* International Journal of Obesity


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More than half of all cases of cancer can be prevented according to Cancer Research UK’;s Reduce the Risk campaign. Link. The campaign’;s key messages are :

  • Stop smoking: It’;s the best present you’;ll ever give yourself
  • Stay in shape: Be active and keep a healthy body weight
  • Eat and drink healthily: Limit alcohol and choose a balanced diet with plenty of fruit and vegetables
  • Be SunSmart: Protect yourself in the sun and take care not to burn
  • Look after number one: Know your body and see your doctor about anything unusual

The European Prospective Investigation into Cancer and Nutrition (EPIC) is an ongoing study into the dietary habits of more than half a million people in Europe.

For more information about different types of cancer, diagnosis and treatment for patients and their families, visit Cancer Research UK’;s patient information website.Cancer Research UK

  • Cancer Research UK’s vision is to conquer cancer through world-class research.
  • The charity works alone and in partnership with others to carry out research into the biology and causes of cancer, to develop effective treatments, improve the quality of life for cancer patients, reduce the number of people getting cancer and to provide authoritative information on cancer. Cancer Research UK is the world’s leading independent charity dedicated to research on the causes, treatment and prevention of cancer.
  • For further information about Cancer Research UK’s work or to find out how to support the charity, please call 020 7009 8820.