Editing Obesity (section)

===Social determinants===
{{Main|Social determinants of obesity}}
[[File:Yamai no Soshi - Obesity.JPG|thumb|upright=1.3|The disease scroll (''Yamai no soshi'', late 12th century) depicts a woman moneylender with obesity, considered a disease of the rich.]]
[[File:More adults are obese in more unequal rich countries (cropped).jpg|thumb|upright=1.3|Obesity in developed countries is correlated with [[economic inequality]].]]

While genetic influences are important to understanding obesity, they cannot completely explain the dramatic increase seen within specific countries or globally.<ref>{{cite journal | vauthors = Yach D, Stuckler D, Brownell KD | title = Epidemiologic and economic consequences of the global epidemics of obesity and diabetes | journal = Nature Medicine | volume = 12 | issue = 1 | pages = 62–6 | date = January 2006 | pmid = 16397571 | doi = 10.1038/nm0106-62 | s2cid = 37456911 }}</ref>{{Better source needed|date=July 2021}} Though it is accepted that energy consumption in excess of energy expenditure leads to increases in body weight on an individual basis, the cause of the shifts in these two factors on the societal scale is much debated. There are a number of theories as to the cause but most believe it is a combination of various factors.

The correlation between [[social class]] and BMI varies globally. Research in 1989 found that in developed countries women of a high social class were less likely to be obese. No significant differences were seen among men of different social classes. In the developing world, women, men, and children from high social classes had greater rates of obesity.{{better source needed|date=July 2021}}<ref>{{cite journal|author-link2=Albert Stunkard| vauthors = Sobal J, Stunkard AJ | title = Socioeconomic status and obesity: a review of the literature | journal = Psychological Bulletin | volume = 105 | issue = 2 | pages = 260–75 | date = March 1989 | pmid = 2648443 | doi = 10.1037/0033-2909.105.2.260 | type = Review }}</ref> In 2007 repeating the same research found the same relationships, but they were weaker. The decrease in strength of correlation was felt to be due to the effects of [[globalization]].<ref name=McLaren2007>{{cite journal | vauthors = McLaren L | title = Socioeconomic status and obesity | journal = Epidemiologic Reviews | volume = 29 | pages = 29–48 | year = 2007 | pmid = 17478442 | doi = 10.1093/epirev/mxm001 | type = Review | doi-access = free }}</ref> Among developed countries, levels of adult obesity, and percentage of teenage children who are overweight, are correlated with [[economic inequality|income inequality]]. A similar relationship is seen among US states: more adults, even in higher social classes, are obese in more unequal states.<ref name="spirit">{{cite book|title=The Spirit Level: Why More Equal Societies Almost Always Do Better | vauthors = Wilkinson R, Picket K |author-link1=Richard G. Wilkinson |publisher=Allen Lane |location=London |isbn=978-1-84614-039-6 |year=2009 |pages=91–101|title-link=The Spirit Level: Why More Equal Societies Almost Always Do Better }}</ref>

Many explanations have been put forth for associations between BMI and social class. It is thought that in developed countries, the wealthy are able to afford more nutritious food, they are under greater social pressure to remain slim, and have more opportunities along with greater expectations for [[physical fitness]]. In [[undeveloped countries]] the ability to afford food, high energy expenditure with physical labor, and cultural values favoring a larger body size are believed to contribute to the observed patterns.<ref name=McLaren2007/> Attitudes toward body weight held by people in one's life may also play a role in obesity. A correlation in BMI changes over time has been found among friends, siblings, and spouses.<ref>{{cite journal | vauthors = Christakis NA, Fowler JH | title = The spread of obesity in a large social network over 32 years | journal = The New England Journal of Medicine | volume = 357 | issue = 4 | pages = 370–9 | date = July 2007 | pmid = 17652652 | doi = 10.1056/NEJMsa066082 | type = Research Support | citeseerx = 10.1.1.581.4893 | s2cid = 264194973 }}</ref> Stress and perceived low social status appear to increase risk of obesity.<ref name="spirit"/><ref>{{cite journal | vauthors = Björntorp P | title = Do stress reactions cause abdominal obesity and comorbidities? | journal = Obesity Reviews | volume = 2 | issue = 2 | pages = 73–86 | date = May 2001 | pmid = 12119665 | doi = 10.1046/j.1467-789x.2001.00027.x | s2cid = 23665421 }}</ref><ref>{{cite journal | vauthors = Goodman E, Adler NE, Daniels SR, Morrison JA, Slap GB, Dolan LM | title = Impact of objective and subjective social status on obesity in a biracial cohort of adolescents | journal = Obesity Research | volume = 11 | issue = 8 | pages = 1018–26 | date = August 2003 | pmid = 12917508 | doi = 10.1038/oby.2003.140 | type = Research Support }}</ref>

Smoking has a significant effect on an individual's weight. Those who quit smoking gain an average of 4.4&nbsp;kilograms (9.7&nbsp;lb) for men and 5.0&nbsp;kilograms (11.0&nbsp;lb) for women over ten years.<ref>{{cite journal | vauthors = Flegal KM, Troiano RP, Pamuk ER, Kuczmarski RJ, Campbell SM | title = The influence of smoking cessation on the prevalence of overweight in the United States | journal = The New England Journal of Medicine | volume = 333 | issue = 18 | pages = 1165–70 | date = November 1995 | pmid = 7565970 | doi = 10.1056/NEJM199511023331801 | doi-access = free }}</ref> However, changing rates of smoking have had little effect on the overall rates of obesity.<ref>{{cite journal | vauthors = Chiolero A, Faeh D, Paccaud F, Cornuz J | title = Consequences of smoking for body weight, body fat distribution, and insulin resistance | journal = The American Journal of Clinical Nutrition | volume = 87 | issue = 4 | pages = 801–9 | date = April 2008 | pmid = 18400700 | doi = 10.1093/ajcn/87.4.801 | type = Review | doi-access = free }}</ref>

In the United States, the number of children a person has is related to their risk of obesity. A woman's risk increases by 7% per child, while a man's risk increases by 4% per child.<ref>{{cite journal | vauthors = Weng HH, Bastian LA, Taylor DH, Moser BK, Ostbye T | title = Number of children associated with obesity in middle-aged women and men: results from the health and retirement study | journal = Journal of Women's Health | volume = 13 | issue = 1 | pages = 85–91 | year = 2004 | pmid = 15006281 | doi = 10.1089/154099904322836492 | type = Comparative Study }}</ref> This could be partly explained by the fact that having dependent children decreases physical activity in Western parents.<ref>{{cite journal | vauthors = Bellows-Riecken KH, Rhodes RE | title = A birth of inactivity? A review of physical activity and parenthood | journal = Preventive Medicine | volume = 46 | issue = 2 | pages = 99–110 | date = February 2008 | pmid = 17919713 | doi = 10.1016/j.ypmed.2007.08.003 | type = Review }}</ref>

In the developing world urbanization is playing a role in increasing rate of obesity. In China overall rates of obesity are below 5%; however, in some cities rates of obesity are greater than 20%.<ref>{{cite web|url=https://www.who.int/dietphysicalactivity/media/en/gsfs_obesity.pdf |title=Obesity and Overweight |publisher=[[World Health Organization]] |access-date=22 February 2009}}</ref> In part, this may be because of urban design issues (such as inadequate public spaces for physical activity).<ref name="Pediatric Fitness"/> Time spent in motor vehicles, as opposed to [[active transportation]] options such as cycling or walking, is correlated with increased risk of obesity.<ref>{{cite journal | vauthors = McCormack GR, Virk JS | title = Driving towards obesity: a systematized literature review on the association between motor vehicle travel time and distance and weight status in adults | journal = Preventive Medicine | volume = 66 | pages = 49–55 | date = September 2014 | pmid = 24929196 | doi = 10.1016/j.ypmed.2014.06.002 | hdl = 1880/115549 | s2cid = 12470420 | hdl-access = free }}</ref><ref>{{cite journal | vauthors = King DM, Jacobson SH | title = What Is Driving Obesity? A Review on the Connections Between Obesity and Motorized Transportation | journal = Current Obesity Reports | volume = 6 | issue = 1 | pages = 3–9 | date = March 2017 | pmid = 28243840 | doi = 10.1007/s13679-017-0238-y | s2cid = 207474312 }}</ref>

[[Malnutrition]] in early life is believed to play a role in the rising rates of obesity in the [[developing world]].<ref name=DC2001>{{cite journal | vauthors = Caballero B | title = Introduction. Symposium: Obesity in developing countries: biological and ecological factors | journal = The Journal of Nutrition | volume = 131 | issue = 3 | pages = 866S–870S | date = March 2001 | pmid = 11238776 | doi = 10.1093/jn/131.3.866s | type = Review | doi-access = free }}</ref> Endocrine changes that occur during periods of malnutrition may promote the storage of fat once more food energy becomes available.<ref name=DC2001/>