TACKLING OBESITY IN ENGLANDChanges <strong>in</strong> eat<strong>in</strong>g patterns and<strong>in</strong>creas<strong>in</strong>gly sedentary lifestyles are themost likely explanation for the upwardtrend <strong>in</strong> obesity2.10 The rapid <strong>in</strong>crease <strong>in</strong> obesity levels has occurred <strong>in</strong> tooshort a time for there to have been significant geneticchanges with<strong>in</strong> the population. It is therefore likely thatthe global obesity problem has been brought aboutprimarily by environmental and behavioural changeswhich have led to a more energy-dense diet and a rise<strong>in</strong> the level of sedentary behaviour.Eat<strong>in</strong>g patterns2.11 Both total energy <strong>in</strong>take and the composition of the dietare important factors <strong>in</strong> <strong>in</strong>fluenc<strong>in</strong>g changes <strong>in</strong> bodyweight. The relationship between changes <strong>in</strong> eat<strong>in</strong>gpatterns and the <strong>in</strong>creas<strong>in</strong>g prevalence of obesity is notclear. Data from the <strong>National</strong> Food Survey 14 show thathousehold energy <strong>in</strong>take <strong>in</strong>creased from the late 1950sto a peak <strong>in</strong> 1970, and s<strong>in</strong>ce then has decl<strong>in</strong>ed. On thisbasis, the major <strong>in</strong>crease <strong>in</strong> the prevalence of obesity <strong>in</strong><strong>England</strong>, s<strong>in</strong>ce 1980, has occurred at a time when theenergy consumed from food appears to have beendecreas<strong>in</strong>g.2.12 However, it is important to note that the fall<strong>in</strong>g trend <strong>in</strong>energy <strong>in</strong>take suggested by the <strong>National</strong> Food Surveydoes not take account of alcoholic and soft dr<strong>in</strong>ks andconfectionery brought home, or food and dr<strong>in</strong>kpurchased and eaten outside the home. In 1998, thesecomponents, which have only been recorded s<strong>in</strong>ce1994, accounted for about an extra 20 per cent ofenergy <strong>in</strong>take. Eat<strong>in</strong>g outside the home is becom<strong>in</strong>g<strong>in</strong>creas<strong>in</strong>gly popular, and surveys <strong>in</strong>dicate that the foodeaten out tends to be higher <strong>in</strong> fat than food consumed<strong>in</strong> the home. Fat has a higher energy density than othercomponents, and fatty foods tend not to satiate theappetite as quickly as foods that are high <strong>in</strong>carbohydrates. Exposure to high fat foods is thought tobe largely responsible for the 'over-eat<strong>in</strong>g effect', alsoknown as 'passive over-consumption', where theappetite fails to regulate adequately the amount ofenergy consumed 10 . The ready availability andextensive market<strong>in</strong>g of highly palatable, energy-densefoods may be contribut<strong>in</strong>g to an <strong>in</strong>creas<strong>in</strong>g tendencytowards over-consumption for those people who do notconsciously regulate their diet.Physical activity patterns2.13 Though comprehensive data on trends <strong>in</strong> the level ofphysical activity <strong>in</strong> the population are not available, theupward trend for obesity appears to parallel a reduction<strong>in</strong> physical activity and a rise <strong>in</strong> sedentary behaviour.A study commissioned by Sport <strong>England</strong>, for example,showed that the proportion of young people spend<strong>in</strong>gtwo or more hours per week <strong>in</strong> curricular school sporthad decreased from 46 per cent <strong>in</strong> 1994 to 33 per cent<strong>in</strong> 1999 15 . Similarly, between 1986 and 1996 theproportion of under 17 year-olds walk<strong>in</strong>g to school fellfrom 59 per cent to 49 per cent, whilst the number ofcar journeys to school nearly doubled 16 . At the sametime, there has been an <strong>in</strong>crease <strong>in</strong> the number of hoursdevoted to many sedentary activities. For example, theaverage person <strong>in</strong> <strong>England</strong> watched over 26 hours oftelevision a week <strong>in</strong> the mid-1990s, compared with13 hours <strong>in</strong> the 1960s 17 .2.14 There is also <strong>in</strong>creas<strong>in</strong>g evidence that many people arenot tak<strong>in</strong>g sufficient exercise to have a significant benefitto their health. Data from studies undertaken <strong>in</strong> <strong>England</strong><strong>in</strong> 1998 1 demonstrated that, us<strong>in</strong>g a criterion of lessthan one 30 m<strong>in</strong>ute period of moderate activity perweek, 23 per cent of men and 26 per cent of womenwere sedentary. A quarter of women and just over a thirdof men engaged <strong>in</strong> regular, moderate activity. Morerecently, the <strong>National</strong> Diet and Nutrition Survey,published <strong>in</strong> 2000, which measured physical activitylevels of young people aged between 7 and 18, showedthat most young people <strong>in</strong> this age group were <strong>in</strong>active,as <strong>in</strong>dicated by time spent <strong>in</strong> moderate or vigorous<strong>in</strong>tensity activities 18 .2.15 A number of factors may have contributed to areduction <strong>in</strong> the amount of physical activity 10 . These<strong>in</strong>clude:nnna reduction <strong>in</strong> occupational exercise. The extraphysical activity <strong>in</strong>volved <strong>in</strong> daily liv<strong>in</strong>g 50 yearsago, compared with today, has been estimated to bethe equivalent of runn<strong>in</strong>g a marathon a week;a reduction <strong>in</strong> exercise due to greater use of the carand wider car ownership;the decl<strong>in</strong>e of walk<strong>in</strong>g as a mode of transport. Onereason for this is heightened fears about personalsafety, which affect some groups of the populationmore than others. For example, children, womenand older people, especially those liv<strong>in</strong>g <strong>in</strong> <strong>in</strong>nercities, are likely to feel particularly vulnerable;nan <strong>in</strong>crease <strong>in</strong> energy-sav<strong>in</strong>g devices <strong>in</strong> publicplaces, such as escalators, lifts and automatic doors;part two13
TACKLING OBESITY IN ENGLANDnnnless opportunities for young people to take physicalexercise. Factors <strong>in</strong>fluenc<strong>in</strong>g this <strong>in</strong>clude <strong>in</strong>creas<strong>in</strong>gfears among parents about their children's safetywhen unsupervised, and a reduction <strong>in</strong> the amountof physical education and sport undertaken <strong>in</strong>some schools;the substitution of physically active leisure withsedentary pastimes such as television, computergames and the <strong>in</strong>ternet;fear of racial harassment and cultural beliefs whichmay prevent people from certa<strong>in</strong> black and m<strong>in</strong>orityethnic groups from tak<strong>in</strong>g exercise. Differentavenues may therefore be required to promotephysical exercise for these groups.2.17 Figure 5 <strong>in</strong>dicates the extent to which obesity <strong>in</strong>creasesthe risks of develop<strong>in</strong>g a number of these diseasesrelative to the non-obese population. The relative risksare based on a comprehensive review of <strong>in</strong>ternationalliterature which we carried out to provide the bestestimates that could be applied to the Englishpopulation (Appendix 6). The basis of the estimatesvaries due to differences <strong>in</strong> the methodologies of thestudies selected, but the table gives a broad <strong>in</strong>dicationof the strength of the association between obesity andeach of the ma<strong>in</strong> secondary disease types.5Estimated <strong>in</strong>creased risk for the obese of develop<strong>in</strong>gassociated diseases, taken from <strong>in</strong>ternational studiesDisease Relative risk - women Relative risk - menThe substantial human costs of obesity2.16 <strong>Obesity</strong> is an important risk factor for a number ofchronic diseases that constitute the pr<strong>in</strong>cipal causes ofdeath <strong>in</strong> <strong>England</strong>, <strong>in</strong>clud<strong>in</strong>g heart disease, stroke andsome cancers. It also contributes to other serious lifeshorten<strong>in</strong>g conditions such as Type 2 diabetes. As wellas physical symptoms, the psychological and socialburdens of obesity can be significant: social stigma, lowself-esteem, reduced mobility and a generally poorerquality of life are common experiences for many obesepeople 10 . Appendix 5 provides an analysis of thespecific l<strong>in</strong>ks between obesity and the most commonserious diseases with which it is associated.Type 2 Diabetes * 12.7 5.2Hypertension 4.2 2.6Myocardial Infarction 3.2 1.5Cancer of the Colon 2.7 3.0Ang<strong>in</strong>a 1.8 1.8Gall Bladder Diseases 1.8 1.8Ovarian Cancer 1.7 -Osteoarthritis 1.4 1.9Stroke 1.3 1.3* Non-<strong>in</strong>sul<strong>in</strong> dependent diabetes mellitus (NIDDM)Note: The BMI range for the obese and non-obese groups used toestimate relative risk varies between studies, which limits thecomparability of these data.Source: <strong>National</strong> <strong>Audit</strong> <strong>Office</strong> estimates based on literature review (Appendix 6)part two14
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