Editing Cancer (section)

=== Diet and exercise ===
{{Main|Diet and cancer}}
{{anchor|Diet}}Diet, [[Sedentary lifestyle|physical inactivity]], and [[obesity]] are related to up to 30–35% of cancer deaths.<ref name=Enviro2008/><ref name="Nutri06">{{cite journal |vauthors=Kushi LH, Byers T, Doyle C, Bandera EV, McCullough M, McTiernan A, Gansler T, Andrews KS, Thun MJ |s2cid=19823935 |title=American Cancer Society Guidelines on Nutrition and Physical Activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity |journal=CA: A Cancer Journal for Clinicians |volume=56 |issue=5 |pages=254–81; quiz 313–14 |year=2006 |pmid=17005596 |doi=10.3322/canjclin.56.5.254|doi-access=free }}</ref> In the United States, excess body weight is associated with the development of many types of cancer and is a factor in 14–20% of cancer deaths.<ref name="Nutri06"/> A UK study including data on over 5 million people showed higher [[body mass index]] to be related to at least 10 types of cancer and responsible for around 12,000 cases each year in that country.<ref name="BhaskaranLancet">{{cite journal |vauthors=Bhaskaran K, Douglas I, Forbes H, dos-Santos-Silva I, Leon DA, Smeeth L |title=Body-mass index and risk of 22 specific cancers: a population-based cohort study of 5·24 million UK adults |journal=Lancet |volume=384 |issue=9945 |pages=755–65 |date=August 2014 |pmid=25129328 |doi=10.1016/S0140-6736(14)60892-8 |pmc=4151483}}</ref> Physical inactivity is believed to contribute to cancer risk, not only through its effect on body weight but also through negative effects on the [[immune system]] and [[endocrine system]].<ref name="Nutri06"/> More than half of the effect from the diet is due to [[overnutrition]] (eating too much), rather than from eating too few vegetables or other healthful foods.{{citation needed|date=March 2024}}

Some specific foods are linked to specific cancers. A high-salt diet is linked to [[gastric cancer]].<ref name=pmid18990005/> [[Aflatoxin B1]], a frequent food contaminant, causes liver cancer.<ref name=pmid18990005/> [[Betel nut]] chewing can cause oral cancer.<ref name="pmid18990005">{{cite journal |vauthors=Park S, Bae J, Nam BH, Yoo KY |title=Aetiology of cancer in Asia |journal=Asian Pacific Journal of Cancer Prevention |volume=9 |issue=3 |pages=371–80 |year=2008 |pmid=18990005 |url=http://www.apocpcontrol.org/page/popup_paper_file_view.php?pno=MzcxIFBhcmsucCZrY29kZT04MjI=&pgubun=i|archive-url=https://web.archive.org/web/20110904052252/http://www.apocpcontrol.org/page/popup_paper_file_view.php?pno=MzcxIFBhcmsucCZrY29kZT04MjI=&pgubun=i |archive-date=4 September 2011}}</ref> National differences in dietary practices may partly explain differences in cancer incidence. For example, [[gastric cancer]] is more common in Japan due to its high-salt diet<ref name="pmid19107449">{{Cite book |vauthors=Brenner H, Rothenbacher D, Arndt V |chapter=Epidemiology of Stomach Cancer |title=Cancer Epidemiology |volume=472 |chapter-url={{google books |plainurl=y |id=5v1JAQAAIAAJ |page=467}}|pages = 467–77 | year = 2009 | pmid = 19107449 | doi = 10.1007/978-1-60327-492-0_23 | isbn = 978-1-60327-491-3 | series = Methods in Molecular Biology |issue=5450 |pmc=2166976 }}</ref> while [[Colorectal cancer|colon cancer]] is more common in the United States. Immigrant cancer profiles mirror those of their new country, often within one generation.<ref name="pmid14278899">{{cite journal |vauthors=Buell P, Dunn JE |title=Cancer Mortality Among Japanese Issei and Nisei of California |journal=Cancer |volume=18 |issue=5 |pages=656–64 |date=May 1965 |pmid=14278899 |doi=10.1002/1097-0142(196505)18:5<656::AID-CNCR2820180515>3.0.CO;2-3|doi-access=free }}</ref>