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. 2008 Feb 2;336(7638):245. doi: 10.1136/bmj.39458.495127.AD

Is the obesity epidemic exaggerated? No

R W Jeffery 1,, N E Sherwood 2
PMCID: PMC2223031  PMID: 18244993

Abstract

The UK health secretary declared last week that we are in the grip of an obesity epidemic. Patrick Basham and John Luik believe that the problem is less clear cut, but R W Jeffery and N E Sherwood say that obesity is a growing global problem


An abundance of observational and experimental data show the growing prevalence of obesity, defined as a body mass index ≥30, and the causal role of obesity in adverse health outcomes. These data substantiate our position that the seriousness of the obesity epidemic is not exaggerated. The fact that obesity is developing rapidly in many parts of the globe is incontrovertible. The World Health Organization’s Global Database on Body Mass Index includes the most comprehensive international data available on obesity trends.1 Absolute prevalence of obesity varies among countries (0.7%- 78.5%). However, large rises in prevalence have been observed across the globe over the past few decades. Rates of obesity in adults have roughly tripled in Japan (from 0.84% in 1980 to 2.86% in 2001), Brazil (from 2.4% in 1974-5 to 8.9% in 2002-3), England (from 6.2% in 1982 to 22.6% in 1999), the United States (from 11.5% in 1990 to 34.1% in 2004), and Seychelles (from 4.2% in 1989 to 15% in 2004) to give a few examples.1

The prevalence of obesity among children and adolescents has also increased greatly. The US National Health and Nutrition Examination Survey indicates that the prevalence of obesity in 1976-80 was 6.5% among 6-11 year olds and 5% among 12-17 year olds. In 2003-4 it was 19% and 17% respectively. These disturbing trends are mirrored in other countries. Prevalence of overweight among school age children has been reported as high as 35% in parts of Europe, and it has been estimated that the European Union can expect to see the numbers of overweight and obese children rising by around 1.3 million a year by 2010.2 A recent review of childhood obesity trends from 25 countries with data on school age children and 42 countries with data on preschool populations shows that obesity has increased in most countries, with the sharpest increases in economically developed countries and urban areas.3

Health effects

The adverse effects of obesity on health are well established, serious, and causal. Overweight and obesity increase the risk of many serious health conditions, including hypertension, hypercholesterolaemia, diabetes, coronary heart disease, and some forms of cancer.4,5,6,7,8,9 A dose-response relation between body mass index and the risk of developing chronic diseases is even observed among adults in the upper half of the “healthy” weight range (that is, body mass index of 22.0-24.9).6

Increases in body weight are strongly associated with increased insulin resistance at the cellular level, which may be a fundamental mechanism driving many disease processes. Three large clinical trials have shown that behavioural interventions targeting weight reduction and physical activity in people with impaired glucose tolerance improve the natural course of diabetes.10,11,12 Lifestyle change with a 7% weight loss delayed the development of type 2 diabetes in high risk individuals by 58% over four years compared with the control group.12

Because effective, sustained weight loss is not easily achieved clinically or by traditional public health education measures,13,14 we are facing the potential for a major health crisis. When will the obesity driven health crisis arrive and how serious it will be has been the subject of much speculation. Not all diseases related to obesity have paralleled obesity trends. For example, the incidence of cardiovascular disease incidence has fallen steeply as body weight has risen, perhaps because of improvements in diet or better treatments for risk factors such as raised blood pressure and blood lipid concentrations.

However, examination of trends in the disease most strongly linked to obesity, diabetes, is very concerning. Data from the Behavioral Risk Factor Surveillance System and the National Ambulatory Medical Care Survey (1995-2004) show that during a period in which the prevalence of overweight and obesity increased by nearly 24%, the prevalence of diabetes increased by about 76% and the number of diabetes related visits to primary care doctors more than doubled.15

Health economists and epidemiologists have made projections about the potential impact of future obesity trends. Most agree that the contribution of obesity to current healthcare costs is high and that it is likely to get much higher.16,17,18 Some have argued that we may even see real falls in life expectancy within a few decades.19

In summary, a large body of scientific evidence documents that overnutrition and obesity are a major global health problem. With the continuing rise in obesity and limited treatment efficacy, options for averting a poor public health outcome seem to rest either on the hope that scientists are wrong in their projections or speedy investment in the development of more effective public health measures to deal with it. We think the second option a more prudent scientific and policy choice.

RWJ is supported in part by National Cancer Institute grant (transdisciplinary research on energetics and cancer) CA116849 and National Institutes of Diabetes and Digestive and Kidney Diseases grant (Minnesota Obesity Center) DK50456.

Competing interests: None declared.

References

  • 1.WHO. Global database on body mass index www.who.int/bmi/index.jsp
  • 2.Jackson-Leach R. Lobstein T. Estimated burden of paediatric obesity and co-morbidities in Europe. 1. The increase in the prevalence of child obesity in Europe is itself increasing. Int J Pediatr Obes 2006;1:26-32. [DOI] [PubMed] [Google Scholar]
  • 3.Wang Y, Lobstein T. Worldwide trends in childhood overweight and obesity. Int J Pediatr Obes 2006;1:11-25. [DOI] [PubMed] [Google Scholar]
  • 4.Gelber RP, Kurth T, Manson JE, Buring JE, Gaziano JM. Body mass index and mortality in men: evaluating the shape of the association. Int J Obes 2007;31:1024-7. [DOI] [PubMed] [Google Scholar]
  • 5.Wilson PW, D’Agostino RB, Sullivan L, Parise H, Kannel WB. Overweight and obesity as determinants of cardiovascular risk: the Framingham experience. Arch Intern Med 2002;162:1867-72. [DOI] [PubMed] [Google Scholar]
  • 6.Field AE, Coakley EH, Must A, Spadano JL, Laird N, Dietz WH, et al. Impact of overweight on the risk of developing common chronic diseases during a 10-year period. Arch Intern Med 2001;161:1581-6. [DOI] [PubMed] [Google Scholar]
  • 7.Chang SC, Lacey JV Jr, Brinton LA, Hartge P, Adams K, Mouw T, et al. Lifetime weight history and endometrial cancer risk by type of menopausal hormone use in the NIH-AARP diet and health study. Cancer Epidemiol Biomarkers Prev 2007;16:723-30. [DOI] [PubMed] [Google Scholar]
  • 8.Wenten M, Gilliland FD, Baumgartner K, Samet JM. Associations of weight, weight change, and body mass with breast cancer risk in Hispanic and non-Hispanic white women. Ann Epidemiol 2002;12:435-44. [DOI] [PubMed] [Google Scholar]
  • 9.Narayan KM, Boyle JP, Thompson TJ, Gregg EW, Williamson DF. Effect of body mass index on lifetime risk for diabetes mellitus in the United States. Diabetes Care 2007;30:1562-6. [DOI] [PubMed] [Google Scholar]
  • 10.Tuomilehto J, Lindstrom J, Eriksson JG, Valle TT, Hämäläinen H, Ilanne-Parikka P, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001;344:1343-50. [DOI] [PubMed] [Google Scholar]
  • 11.Pan XR, Li GW, Hu YH, Wang JX, Yang WY, An ZX, et al. Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance. The Da Qing IGT and diabetes study. Diabetes Care 1997;20:537-44. [DOI] [PubMed] [Google Scholar]
  • 12.Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002;346:393-403. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Jeffery RW, Drewnowski A, Epstein LH, Stunkard AJ, Wilson GT, Wing RR, et al. Long-term maintenance of weight loss: Current status. Health Psychol 2000;19(suppl):1-12. [DOI] [PubMed] [Google Scholar]
  • 14.Jeffery RW. Public health strategies for obesity treatment and prevention. Am J Health Behav 2001;25:252-9. [DOI] [PubMed] [Google Scholar]
  • 15.Pearson WS. Ten-year comparison of estimates of overweight and obesity, diagnosed diabetes and use of office-based physician services for treatment of diabetes in the United States. Prev Med 2007;45:353-357. [DOI] [PubMed] [Google Scholar]
  • 16.Thompson D, Wolf AM. The medical-care cost burden of obesity. Obes Rev 2001;2:189-97. [DOI] [PubMed] [Google Scholar]
  • 17.Finkelstein EA, Brown DS, Trogdon JG, Segel JE, Ben-Joseph RH. Age-specific impact of obesity on prevalence and costs of diabetes and dyslipidemia. Value Health 2007;10:S45-51. [Google Scholar]
  • 18.Wang F, Schultz AB, Musich S, McDonald T, Hirschland D, Edington DW. The relationship between National Heart, Lung, and Blood Institute weight guidelines and concurrent medical costs in a manufacturing population. Am J Health Promot 2003;17:183-9. [DOI] [PubMed] [Google Scholar]
  • 19.Olshansky SJ, Passaro DJ, Hershow RC, Layden J, Carnes BA, Brody J, et al. A potential decline in life expectancy in the United States in the 21st century. N Engl J Med 2005;352:1138-45. [DOI] [PubMed] [Google Scholar]

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