Tackling Obesity in England - National Audit Office

TACKLING OBESITY IN ENGLANDChanges in eating patterns andincreasingly sedentary lifestyles are themost likely explanation for the upwardtrend in obesity2.10 The rapid increase in obesity levels has occurred in tooshort a time for there to have been significant geneticchanges within 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 risein the level of sedentary behaviour.Eating patterns2.11 Both total energy intake and the composition of the dietare important factors in influencing changes in bodyweight. The relationship between changes in eatingpatterns and the increasing prevalence of obesity is notclear. Data from the National Food Survey 14 show thathousehold energy intake increased from the late 1950sto a peak in 1970, and since then has declined. On thisbasis, the major increase in the prevalence of obesity inEngland, since 1980, has occurred at a time when theenergy consumed from food appears to have beendecreasing.2.12 However, it is important to note that the falling trend inenergy intake suggested by the National Food Surveydoes not take account of alcoholic and soft drinks andconfectionery brought home, or food and drinkpurchased and eaten outside the home. In 1998, thesecomponents, which have only been recorded since1994, accounted for about an extra 20 per cent ofenergy intake. Eating outside the home is becomingincreasingly popular, and surveys indicate that the foodeaten out tends to be higher in fat than food consumedin 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 incarbohydrates. Exposure to high fat foods is thought tobe largely responsible for the 'over-eating effect', alsoknown as 'passive over-consumption', where theappetite fails to regulate adequately the amount ofenergy consumed 10 . The ready availability andextensive marketing of highly palatable, energy-densefoods may be contributing to an increasing tendencytowards over-consumption for those people who do notconsciously regulate their diet.Physical activity patterns2.13 Though comprehensive data on trends in the level ofphysical activity in the population are not available, theupward trend for obesity appears to parallel a reductionin physical activity and a rise in sedentary behaviour.A study commissioned by Sport England, for example,showed that the proportion of young people spendingtwo or more hours per week in curricular school sporthad decreased from 46 per cent in 1994 to 33 per centin 1999 15 . Similarly, between 1986 and 1996 theproportion of under 17 year-olds walking 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 increase in the number of hoursdevoted to many sedentary activities. For example, theaverage person in England watched over 26 hours oftelevision a week in the mid-1990s, compared with13 hours in the 1960s 17 .2.14 There is also increasing evidence that many people arenot taking sufficient exercise to have a significant benefitto their health. Data from studies undertaken in Englandin 1998 1 demonstrated that, using a criterion of lessthan one 30 minute 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 in regular, moderate activity. Morerecently, the National Diet and Nutrition Survey,published in 2000, which measured physical activitylevels of young people aged between 7 and 18, showedthat most young people in this age group were inactive,as indicated by time spent in moderate or vigorousintensity activities 18 .2.15 A number of factors may have contributed to areduction in the amount of physical activity 10 . Theseinclude:nnna reduction in occupational exercise. The extraphysical activity involved in daily living 50 yearsago, compared with today, has been estimated to bethe equivalent of running a marathon a week;a reduction in exercise due to greater use of the carand wider car ownership;the decline of walking 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 living in innercities, are likely to feel particularly vulnerable;nan increase in energy-saving devices in publicplaces, such as escalators, lifts and automatic doors;part two13