Be as lean as possible within the normal range of body weight
To date, the range of normal weight has been usually identified as a BMI between 18.5 and 24.9
The evidence reviewed by the Panel more often than not does not show thresholds of food and drink consumption, body fatness, or physical activity below or above which the risk of cancer suddenly changes.
Restriction of energy intake from food is the most effective single intervention for preventing cancer in experimental animals. It increases the lifespan of rodents, and suppresses tumour development in mice. In addition, energy restriction can suppress the pro-cancer effects of many carcinogens in experimental animal models.
Food, Nutrition, Physical Activity, and the Prevention of Cancer:
a Global Perspective
World Cancer Research Fund and American Institute for Cancer Research.
What a pleasure and a privilege to spend three years in the company of a remarkable group of scientists, including world leaders in research on the epidemiology of cancer, as well as leaders in nutrition and public health and the biology of cancer, to use a relatively new methodology (systematic literature reviews), supported by a vigorous and highly effective Secretariat, on an issue of profound importance to global public health: the prevention of cancer by means of healthy patterns of eating and physical activity.
In general, recommendations in this Report to prevent cancer will also be of great relevance to cardiovascular disease.
The fact that the conclusions and recommendations in this Report are the unanimous view of the Panel does not imply that, miraculously, experts have stopped disagreeing.
None of our recommendations is based on these ‘could be’ conclusions. All are based on judgements that evidence was definite or probable. Our recommendations, we trust, will serve as guides to the population, to scientists, and to opinion-formers.
But the Panel agrees, as evident in Chapters 10 and 12, that many chronic diseases, including type 2 diabetes and its precursors, cardiovascular diseases and their precursors, and also perhaps other diseases of the digestive, musculoskeletal, and nervous systems, are to a large extent caused by environmental factors, including inappropriate food and nutrition, physical inactivity, overweight and obesity, and associated factors.
The estimate of the previous WCRF/AICR Report was that cancer is 30 to 40 per cent preventable over time, by appropriate food and nutrition, regular physical activity, and avoidance of obesity.
The evidence that the factors that lead to greater adult attained height, or its consequences, increase the risk of cancers of the colorectum and breast (postmenopause) is convincing; and they probably also increase the risk of cancers of the pancreas, breast (premenopause) and ovary. In addition, the factors that lead to greater birth weight, or its consequences, are probably a cause of premenopausal breast cancer.
Identifying optimal growth trajectories that protect health not only in childhood but also throughout life is a major challenge for the research and public health communities.