Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective World Cancer Research Fund American Institute for Cancer Research Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective World Cancer Research Fund American Institute for Cancer Research Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective The most definitive review of the science to date, and the most authoritative basis for action to prevent cancer worldwide. u Recommendations based on expert judgements of systematic reviews of the world literature. u The result of a five-year examination by a panel of the world’s leading scientists. u Includes new findings on early life, body fatness, physical activity, and cancer survivors. u Recommendations harmonised with prevention of other diseases and promotion of well-being. u A vital guide for everybody, and the indispensable text for policy-makers and researchers. SECOND EXPERT REPORT Fonds Mondial de Recherche contre le Cancer World Cancer Research Fund World Cancer Research Fund Hong Kong World Cancer Research Fund International Wereld Kanker Onderzoek Fonds American Institute for Cancer Research www.wcrf.org www.aicr.org www.wcrf-uk.org www.wcrf-nl.org www.wcrf-hk.org www.fmrc.fr ER HARD FINAL.indd 1 30/10/07 10:07:25 a Global Perspective FFoooodd,, NNuuttrriittiioonn,, PPhhyyssiiccaall AAccttiivviittyy,, aanndd tthhee PPrreevveennttiioonn ooff CCaanncceerr:: Please cite the Report as follows: World Cancer Research Fund / American Institute for Cancer Research. Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. Washington DC: AICR, 2007 First published 2007 by the American Institute for Cancer Research 1759 R St. NW, Washington, DC 20009 © 2007 World Cancer Research Fund International All rights reserved Readers may make use of the text and graphic material in this Report for teaching and personal purposes, provided they give credit to World Cancer Research Fund and American Institute for Cancer Research. ISBN: 978-0-9722522-2-5 CIP data in process Printed in the United States of America by RR Donnelley a Global Perspective FFoooodd,, NNuuttrriittiioonn,, PPhhyyssiiccaall AAccttiivviittyy,, aanndd tthhee PPrreevveennttiioonn ooff CCaanncceerr:: A project of World Cancer Research Fund International iv I am very grateful to the special group of distinguished scientists who made up the Panel and Secretariat for this major review of the evidence on food, nutrition, physical activity and cancer. The vision of WCRF International in convening this Panel and confidence in letting a strong-willed group of scientists have their way is to be highly commended. In our view, the evidence reviewed here that led to our recommendations provides a wonderful opportunity to prevent cancer and improve global health. Individuals and populations have in their hands the means to lead fuller, healthier lives. Achieving that will take action, globally, nationally, and locally, by communities, families, and individuals. It is worth pausing to put this Report in context. Public perception is often that experts disagree. Why should the public or policy-makers heed advice if experts differ in their views? Experts do disagree. That is the nature of science and a source of its strength. Should we throw up our hands and say one opinion is as good as another? Of course not. Evidence matters. But not evidence unguided by human thought. Hence the process that was set up for this review: use a systematic approach to examine all the relevant evidence using predetermined criteria, and assemble an international group of experts who, having brought their own knowledge to bear and having debated their disagreements, arrive at judgements as to what this evidence means. Both parts of the exercise were crucial: the systematic review and, dare I say it, the wisdom of the experts. The elegance of the process was one of the many attractions to me of assuming the role of chair of the Panel. I could pretend that it was the major reason, and in a way it was, but the first reason was enjoyment. 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. It was quite as enjoyable as anticipated. Given this heady mix, the reasons why I might have wanted to take on the role of Panel chair were obvious. I did question the wisdom of WCRF International in inviting me to do it. Much of my research has been on cardiovascular disease, not cancer. What I described as my ignorance, WCRF International kindly labelled impartiality. WCRF also appreciated the parallels between dietary causes of cardiovascular disease and cancer. There is a great deal of concordance. In general, recommendations in this Report to prevent cancer will also be of great relevance to cardiovascular disease. The only significant contradiction is with alcohol. From the point of view of cancer prevention, the best level of alcohol consumption is zero. This is not the case for cardiovascular disease, where the evidence suggests that one to two drinks a day are protective. The Panel therefore framed its recommendation to take this into account. 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. The Panel debated the fine detail of every aspect of its conclusions and recommendations with remarkable vigour and astonishing stamina. In my view, this was deliberation at its best. If conclusions could simply fall out of systematic literature reviews, we would not have needed experts to deliberate. Human judgement was vital; and if human, it cannot be infallible. But I venture to suggest this process has led to as good an example of evidence- based public health recommendations as one can find. Throughout the Panel’s deliberations, it had in mind the global reach of this Report. Most of the research on diet and cancer comes from high-income countries. But PPrreeffaaccee v noncommunicable diseases, including cancer, are now major public health burdens in every region of the world. An important part of our deliberations was to ensure the global applicability of our recommendations. One last point about disagreement among experts: its relevance to the link between science and policy. A caricature would be to describe science as precise and policy-makers as indecisive. In a way, the opposite is the case. Science can say: could be, might be, some of us think this, and some think that. Policy-makers have either to do it or not do it — more often, not. Our effort here was to increase the precision of scientific judgements. As the Report makes clear, many of our conclusions are in the ‘could be’ category. 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 what should policy-makers do with our judgements? A year after publication of this Report, we will publish a second report on policy for diet, nutrition, physical activity, and the prevention of cancer. As an exercise developing out of this one, we decided to apply, as far as possible, the same principles of synthesis of evidence to policy-making. We enhanced the scientific panel that was responsible for this Report with experts in nutrition and food policy. This policy panel will oversee systematic literature reviews on food policy, deliberate, and make recommendations. The current Report and next year’s Policy Report have one overriding aim: to reduce the global burden of cancer by means of healthier living. Michael Marmot vi PPrreeffaaccee ii vv CCoonntteennttss vv ii AAcckknnoowwlleeddggeemmeennttss vviiiiii SSuummmmaarryy xx ii vv IInnttrroodduuccttiioonn xxxxiiii ■■ PPAARRTT OONNEE BBAACCKKGGRROOUUNNDD 11 CChhaapptteer r 11 IInntteerrnnaattiioonnaall vvaarriiaattiioonnss aanndd ttrreennddss 44 1.1 Food systems and diets throughout history 5 1.2 Foods and drinks, physical activity, body composition 11 1.3 Migrant and other ecological studies 22 1.4 Conclusions 25 CChhaapptteerr 22 TThhee ccaanncceerr pprroocceessss 3300 2.1 Basic concepts and principles 31 2.2 Cellular processes 32 2.3 Carcinogen metabolism 36 2.4 Causes of cancer 37 2.5 Nutrition and cancer 41 2.6 Conclusions 46 CChhaapptteerr 33 JJuuddggiinngg tthhee eevviid deennccee 4488 3.1 Epidemiological evidence 49 3.2 Experimental evidence 52 3.3 Methods of assessment 55 3.4 Causation and risk 57 3.5 Coming to judgement 58 3.6 Conclusions 62 ■■ PPAARRTT TTWWOO EEVVIIDDEENNCCEE AANNDD JJUUDDGGEEMMEENNTTSS 6633 CChhaapptteerr 44 FFooooddss aanndd ddrriinnkkss 6666 4.1 Cereals (grains), roots, tubers and plantains 67 4.2 Vegetables, fruits, pulses (legumes), nuts, seeds, herbs, spices 75 4.3 Meat, poultry, fish and eggs 116 4.4 Milk, dairy products 129 4.5 Fats and oils 135 4.6 Sugars and salt 141 4.7 Water, fruit juices, soft drinks and hot drinks 148 4.8 Alcoholic drinks 157 4.9 Food production, processing, preservation and preparation 172 4.10 Dietary constituents and supplements 179 4.11 Dietary patterns 190 CChhaapptteerr 55 PPhhyyssiiccaall a accttiivviittyy 119988 CChhaapptteerr 66 GGrroowwtthh,, ddeevveellooppmmeenntt,, bbooddyy ccoommppoossiittiioonn 221100 6.1 Body fatness 211 6.2 Growth and development 229 6.3 Lactation 239 CChhaapptteerr 77 CCaanncceerrss 224444 7.1 Mouth, pharynx and larynx 245 7.2 Nasopharynx 250 7.3 Oesophagus 253 7.4 Lung 259 7.5 Stomach 265 7.6 Pancreas 271 7.7 Gallbladder 275 7.8 Liver 277 7.9 Colon and rectum 280 7.10 Breast 289 7.11 Ovary 296 7.12 Endometrium 299 7.13 Cervix 302 7.14 Prostate 305 7.15 Kidney 310 7.16 Bladder 312 7.17 Skin 315 7.18 Other cancers 318 CChhaapptteerr 88 DDe etteerrmmiinnaannttss ooff wweeiigghhtt ggaaiinn,, oovveerrwweeiigghhtt,, oobbeessiittyy 332222 CChhaapptteerr 99 CCaanncceerr ssuurrvviivvoorrss 334422 CChhaapptteerr 1100 FFiinnddiinnggs s ooff ootthheerr rreeppoorrtt ss 334488 10.1 Method 349 10.2 Interpretation of the data 350 10.3 Nutritional deficiencies 350 10.4 Infectious diseases 351 10.5 Chronic diseases other than cancer 352 10.6 Cancer 355 10.7 Conclusions 358 CChhaapptteerr 1111 RReesseeaarrcchh iissssuueess 336600 ■■ PPAARRTT TTHHRREEEE RREECCOOMMMMEENNDDAATTIIOONNSS 336655 CChhaapptteerr 1122 PPuubbl liicc hheeaalltthh ggooaallss aanndd ppeerrssoonnaall rreeccoommmmeennddaattiioonnss 336688 12.1 Principles 369 12.2 Goals and recommendations 373 12.3 Patterns of food, nutrition and physical activity 391 AAPPPPEENNDDIICCEESS 339955 AAppppeennddiixx AA PPrroojjeecctt pprroocceessss 339966 AA ppppeennddiixx BB TThhee ffiirrsstt WWCCRRFF//AAIICCRR EExxppeerrtt RReeppoorrtt 339988 AAppppeennddiixx CC WWCCRRFF gglloobbaall nneettwwoorrkk 440000 GGlloossssaarryy 440022 RReeffeerreenncceess 441100 IInnddeexx 550066 CCoonntteennttss vii CCHHAAPPTTEERR BBOOXXEESS ■■ PPAARRTT OONNEE BBAACCKKGGRROOUUNNDD CChhaapptteerr 11 IInntteerrnnaattiioonnaall vvaarriiaattiioonnss aanndd ttrreennddss Box Egypt 6 Box South Africa 8 Box China 10 Box 1.1 Measurement of food supply and consumption 13 Box India 14 Box Japan 16 Box UK 18 Box 1.2 Measurement of cancer incidence and mortality 18 Box Poland 20 Box Spain 22 Box USA 24 Box Mexico 26 Box Australia 27 Box Brazil 28 CChhaapptteerr 22 TTh hee ccaanncceerr pprroocceessss Box 2.1 Nutrition over the life course 34 Box 2.2 Oncogenes and tumour suppressor genes 35 Box 2.3 Mechanisms for DNA repair 37 Box 2.4 Body fatness and attained height 39 Box 2.5 Energy restriction 46 CChhaapptteerr 33 JJuuddggiinngg tthhee eevviiddeennccee Box 3.1 Issues concerning interpretation of the evidence 50 Box 3.2 Dose-response 52 Box 3.3 Forest plots 53 Box 3.4 Systematic literature reviews 54 Box 3.5 Experimental findings 55 Box 3.6 Effect modification 56 Box 3.7 Energy adjustment 57 Box 3.8 Criteria for grading evidence 60 ■■ PPAARRTT TTWWOO EEVVIIDDEENNCCEE AANNDD JJUUDDGGEEMMEENNTTSS CChhaapptteerr 44 FFo oooddss aanndd ddrriinnkkss Box 4.1.1 Wholegrain and refined cereals and their products 69 Box 4.1.2 Foods containing dietary fibre 69 Box 4.1.3 Glycaemic index and load 69 Box 4.1.4 Aflatoxins 70 Box 4.2.1 Micronutrients and other bioactive compounds and cancer risk 78 Box 4.2.2 Phytochemicals 79 Box 4.2.3 Preparation of vegetables and nutrient bioavailability 79 Box 4.2.4 Foods containing dietary fibre 80 Box 4.3.1 Processed meat 117 Box 4.3.2 Nitrates, nitrites and N-nitroso compounds 118 Box 4.3.3 Foods containing iron 118 Box 4.3.4 Heterocyclic amines and polycyclic aromatic hydrocarbons 119 Box 4.3.5 Cantonese-style salted fish 120 Box 4.4.1 Foods containing calcium 131 Box 4.5.1 Hydrogenation and trans-fatty acids 137 Box 4.6.1 Sugar, sugars, sugary foods and drinks 142 Box 4.6.2 Salt and salty, salted and salt-preserved foods 143 Box 4.6.3 Chemical sweeteners 143 Box 4.6.4 Refrigeration 144 Box 4.7.1 High temperature, and irritant drinks and foods 150 Box 4.7.2 Contamination of water, and of foods and other drinks 150 Box 4.8.1 Types of alcoholic drink 159 Box 4.9.1 Food systems 173 Box 4.9.2 ‘Organic’ farming 174 Box 4.9.3 Regulation of additives and contaminants 175 Box 4.9.4 Water fluoridation 176 Box 4.10.1 Food fortification 182 Box 4.10.2 Functional foods 182 Box 4.10.3 Levels of supplementation 183 CChhaapptteerr 55 PPhhyyssiiccaall aaccttiivviittyy Box 5.1 Energy cost and intensity of activity 200 Box 5.2 Sedentary ways of life 201 CChhaapptteerr 66 GGrroowwtthh,, ddeevveellooppmmeenntt,, bbood dyy ccoommppoossiittiioonn Box 6.2.1 Sexual maturity 232 Box 6.2.2 Age at menarche and risk of breast cancer 232 CChhaapptteerr 77 CCaanncceerrss Box 7.1.1 Cancer incidence and survival 246 Box 7.2.1 Epstein-Barr virus 251 Box 7.5.1 Helicobacter pylori 266 Box 7.8.1 Hepatitis viruses 278 Box 7.13.1 Human papilloma viruses 303 CChhaapptteerr 88 DDeetteerrmmiinnaannttss ooff wweeiigghhtt ggaaiinn,, oovveerrwweeiigghhtt,, oobbeessiittyy Box 8.1 Energy density 324 Box 8.2 Fast food 325 Box 8.3 Body fatness in childhood 326 Box 8.4 Television viewing 331 CC hhaapptteerr 99 CCaanncceerr ssuurrvviivvoorrss Box 9.1 Conventional and unconventional therapies 345 Box 9.2 Use of supplements by cancer survivors 346 CChhaapptteerr 1100 FFiinnddiinnggss ooff ootthheerr rreeppoorrtt ss CChhaapptteerr 1111 RReesseeaarrcchh iissssuueess ■■ PPAARRTT TTHHR REEEE RREECCOOMMMMEENNDDAATTIIOONNSS CChhaapptteerr 1122 PPuubblliicc hheeaalltthh ggooaallss aanndd ppeerrssoonnaall rreeccoommmmeennddaattiioonnss Box 12.1 Quantification 371 Box 12.2 Making gradual changes 372 Box 12.3 Height, weight and ranges of BMI 375 Box 12.4 When supplements are advisable 387 Box 12.5 Regional and special circumstances 392 viii FOOD, NUTRITION, PHYSICAL ACTIVITY, AND THE PREVENTION OF CANCER: A GLOBAL PERSPECTIVE Panel Sir Michael Marmot MB BS MPH PhD FRCP FFPH Chair University College London UK Tola Atinmo PhD University of Ibadan, Nigeria Tim Byers MD MPH University of Colorado Health Sciences Center Denver, CO, USA Junshi Chen MD Chinese Centre for Disease Control and Prevention Beijing, People’s Republic of China Tomio Hirohata MD DrScHyg PhD Kyushu University Fukuoka City, Japan Alan Jackson CBE MD FRCP FRCPCH FRCPath University of Southampton UK W Philip T James CBE MD DSc FRSE FRCP International Obesity Task Force London, UK Laurence N Kolonel MD PhD University of Hawai’i Honolulu, HI, USA Shiriki Kumanyika PhD MPH University of Pennsylvania Philadelphia, PA, USA Claus Leitzmann PhD Justus Liebig University Giessen, Germany Jim Mann DM PhD FFPH FRACP University of Otago Dunedin, New Zealand Hilary J Powers PhD RNutr University of Sheffield, UK K Srinath Reddy MD DM MSc Institute of Medical Sciences New Delhi, India Elio Riboli MD ScM MPH Was at: International Agency for Research on Cancer (IARC), Lyon, France Now at: Imperial College London, UK Juan A Rivera PhD Instituto Nacional de Salud Publica Cuernavaca, Mexico Arthur Schatzkin MD DrPH National Cancer Institute Rockville, MD, USA Jacob C Seidell PhD Free University Amsterdam The Netherlands David E G Shuker PhD FRSC The Open University Milton Keynes, UK Ricardo Uauy MD PhD Instituto de Nutricion y Tecnologia de los Alimentos Santiago, Chile Walter C Willett MD DrPH Harvard School of Public Health Boston, MA, USA Steven H Zeisel MD PhD University of North Carolina Chapel Hill, NC, USA Robert Beaglehole ONZM FRSNZ DSc Chair 2003 Was at: World Health Organization (WHO) Geneva, Switzerland Now at: University of Auckland, New Zealand Panel observers Food and Agriculture Organization of the United Nations (FAO) Rome, Italy Guy Nantel PhD Prakash Shetty MD PhD International Food Policy Research Institute (IFPRI) Washington DC, USA Lawrence Haddad PhD Marie Ruel PhD International Union of Nutritional Sciences (IUNS) Mark Wahlqvist MD AO Mechanisms Working Group John Milner PhD Methodology Task Force Jos Kleijnen MD PhD Gillian Reeves PhD Union Internationale Contre le Cancer (UICC) Geneva, Switzerland Annie Anderson PhD Curtis Mettlin PhD Harald zur Hausen MD DSc United Nations Children’s Fund (UNICEF) New York, NY, USA Ian Darnton-Hill MD MPH Rainer Gross Dr Agr World Health Organization (WHO) Geneva, Switzerland Denise Coitinho PhD Ruth Bonita MD Chizuru Nishida PhD MA Pirjo Pietinen DSc Additional members for policy panel Barry Popkin PhD MSc BSc Carolina Population Center, University of North Carolina, Chapel Hill, NC, USA Jane Wardle PhD MPhil University College London, UK Nick Cavill MPH British Heart Foundation Health Promotion Research Group University of Oxford, UK AAcckknnoowwlleeddggeemmeennttss ix ACKNOWLEDGEMENTS Systematic Literature Review Centres UUnniivveerrssiittyy ooff BBrriissttooll,, UUKK George Davey Smith FMedSci FRCP DSc University of Bristol , UK Jonathan Sterne PhD MSc MA University of Bristol, UK Chris Bain MB BS MS MPH University of Queensland Brisbane, Australia Nahida Banu MB BS University of Bristol, UK Trudy Bekkering PhD University of Bristol, UK Rebecca Beynon MA BSc University of Bristol, UK Margaret Burke MSc University of Bristol, UK David de Berker MB BS MRCP United Bristol Healthcare Trust, UK Anna A Davies MSc BSc University of Bristol, UK Roger Harbord MSc University of Bristol, UK Ross Harris MSc University of Bristol, UK Lee Hooper PhD SRD University of East Anglia Norwich, UK Anne-Marie Mayer PhD MSc University of Bristol, UK Andy Ness PhD FFPHM MRCP University of Bristol, UK Rajendra Persad ChM FEBU FRCS United Bristol Healthcare Trust & Bristol Urological Institute, UK Massimo Pignatelli MD PhD FRCPath University of Bristol, UK Jelena Savovic PhD University of Bristol, UK Steve Thomas MB BS PhD FRCS University of Bristol, UK Tim Whittlestone MA MD FRCS United Bristol Healthcare Trust, UK Luisa Zuccolo MSc University of Bristol, UK IIssttiittuuttoo NNaazziioonnaallee TTuummoorrii MMiillaann, , IIttaallyy Franco Berrino MD Istituto Nazionale Tumori Milan, Italy Patrizia Pasanisi MD MSc Istituto Nazionale Tumori Milan, Italy Claudia Agnoli ScD Istituto Nazionale Tumori Milan, Italy Silvana Canevari ScD Istituto Nazionale Tumori Milan, Italy Giovanni Casazza ScD Istituto Nazionale Tumori Milan, Italy Elisabetta Fusconi ScD Istituto Nazionale Tumori Milan, Italy Carlos A Gonzalez PhD MPH MD Catalan Institute of Oncology Barcelona, Spain Vittorio Krogh MD MSc Istituto Nazionale Tumori Milan, Italy Sylvie Menard ScD Istituto Nazionale Tumori Milan, Italy Eugenio Mugno ScD Istituto Nazionale Tumori Milan, Italy Valeria Pala ScD Istituto Nazionale Tumori Milan, Italy Sabina Sieri ScD Istituto Nazionale Tumori Milan, Italy JJoohhnnss HHooppkkiinnss UUnniivveerrssiittyy,, BBaallttiimmoorree,, MMDD,, UUSSAA Anthony J Alberg PhD MPH University of South Carolina Columbia, SC, USA Kristina Boyd MS Johns Hopkins University Baltimore, MD, USA Laura Caulfield PhD Johns Hopkins University Baltimore, MD, USA Eliseo Guallar MD DrPH Johns Hopkins University Baltimore, MD, USA James Herman MD Johns Hopkins University Baltimore, MD, USA Genevieve Matanoski MD DrPH Johns Hopkins University Baltimore, MD, USA Karen Robinson MSc Johns Hopkins University Baltimore, MD, USA Xuguang (Grant) Tao MD PhD Johns Hopkins University Baltimore, MD, USA UUnniiv veerrssiittyy ooff LLeeeeddss,, UUKK David Forman PhD FFPH University of Leeds, UK Victoria J Burley PhD MSc RPHNutr University of Leeds, UK Janet E Cade PhD BSc RPHNutr University of Leeds, UK Darren C Greenwood MSc University of Leeds, UK Doris S M Chan MSc University of Leeds, UK Jennifer A Moreton PhD MSc University of Leeds, UK James D Thomas University of Leeds, UK Yu-Kang Tu PhD MSc DDS University of Leeds, UK Iris Gordon MSc University of Leeds, UK Kenneth E L McColl FRSE FMedSci FRCP Western Infirmary Glasgow, UK Lisa Dyson MSc University of Leeds, UK [...]... such as cassava (manioc), yams, potatoes, and also plantains Pulses (legumes) are also farmed to ensure agricultural and nutritional balance; and other crops such as vegetables and fruits are also cultivated Birds and animals are domesticated and bred for food, and fish and seafood contribute to the diets of communities living beside water.57 As with gatherer–hunters, the diets of peasant–agricultural... within Africa, Asia, and Latin America have generally experienced comparatively high rates of cancers of the upper 4 aerodigestive tract (of the mouth, pharynx, larynx, nasopharynx, and oesophagus), and of the stomach, liver (primary), and cervix Rates of some cancers, especially stomach cancer, are now generally decreasing In contrast, high-income countries, and urbanised and industrialised areas of middle-... shifts in patterns of diet and physical activity.53 These points generally also apply to pastoralist societies 1.1.2 Peasant–agricultural In recent millennia, and until very recently in history, almost all human populations have been rural and mostly peasant–agricultural, and the majority still are in most regions of Asia, many regions of Africa, and some parts of Latin America Peasant–agricultural food... and South Africa (Africa); China, India, and Japan (Asia); the UK, Poland, and Spain (Europe); the USA, Brazil, and Mexico (the Americas); and Australia (AsiaPacific).1-47 A N D T R E N D S 1.1 Food systems and diets: historical and current Throughout history, food systems, and thus human diets, have been and are shaped by climate, terrain, seasons, location, culture, and technology They can be grouped... clearing of land to rear cattle and sheep, and the development of railways, refrigeration, and other technologies, have made meat, milk, and their products cheap and plentiful all year round Sugar derived from cane is the most profitable edible cash crop, and sugars and syrups made from cane, beet, and now also corn are used to sweeten and preserve breakfast foods, baked foods, desserts, soft drinks, and a. .. sedentary ways of life are a cause of these cancers and of weight gain, overweight, and obesity Weight gain, overweight, and obesity are also causes of some cancers independently of the level of physical activity Further details of evidence and judgements can be found in Chapters 5, 6, and 8 The evidence summarised in Chapter 10 also shows that physical activity protects against other diseases and that... the incidence of cancer P a r t 1 — B a c k g ro u n d Chapter 1 shows that patterns of production and consumption of food and drink, of physical activity, and of body composition have changed greatly throughout human history Remarkable changes have taken place as a result of urbanisation and industrialisation, at first in Europe, North America, and other economically advanced countries, and increasingly... that patterns of production and consumption of food and drink, of physical activity, and of body composition have changed greatly throughout different periods of human history Remarkable changes have taken place as a result of urbanisation and industrialisation, at first in Europe, North America, and other economically advanced countries, and increasingly in most countries in the world With the establishment... the locally recommended four portions of fruits and vegetables each day, while a quarter eats none.10 from rural to urban areas, there have been rapid and profound changes in both the nature and quality of their foods and drinks, and the patterns of diseases they suffer.71 Urban–industrial food systems have evidently improved people’s strength and health in early life They are also a factor in the doubling... composition and stature, their life expectancy, and patterns of disease, including cancer With the move to urban–industrial ways of life, populations have become taller and heavier, their life expectancy has increased, and they are usually adequately nourished (although poverty, and even destitution, remains a major problem in most big cities) On the other hand, urban populations are at increased risk of chronic . nutritional and other biological and associated factors that modify the risk of can- cer. The Panel is aware that as with other diseases, the risk of cancer. elegance of the process was one of the many attractions to me of assuming the role of chair of the Panel. I could pretend that it was the major reason, and