Dr Elizabeth Poskitt, London School of Hygiene and Tropical Medicine, on 18 July 2003

The speaker is an eminent pediatrician, specializing in malnutrition and obesity, who has founded the European Childhood Obesity Group in order to co-ordinate research on that condition. She has worked in Birmingham, Liverpool and now London, and teaches on higher degree courses. Following extensive clinical work in Africa (which she discussed at the Institution at a lunch meeting last year) she continues to visit overseas medical centres.

Dr Poskitt began by noting that her African experience prompted parallels between England in 1000 AD and Africa today, insofar as seasonal summer food shortages are considered, since our current access to ‘plenty of food at all times of the year’ was not true in the past nor elsewhere today. Where societies are becoming more westernized, however, obesity is becoming a problem. We shadow the ‘horrors of America’ and some developing countries now are shadowing us with respect to obesity problems.

We should recognize that being overweight is not merely a fashion issue – it has serious medical implications. The ancient Greeks saw longevity implications, as we do now with regard to smoking. The ratio of weight to height gives a broad definition of obesity for adults in terms of the ‘body mass index’, but that does not in itself measure fatness. Beyond an index count of 30 to 40 ‘morbid obesity’ brings higher death rates, although underweight people are apparently at lower risk. In some countries where body mass indexes are at European levels (as in India) an excess of fat produces higher mortality levels, however.

The problem of overweight children began to be noticed in the West in the 1990s. Obesity in Europe is generally above 15% of population and in some above 35/40% (e.g. Poland, Israel, Yugoslavia). In Britain over the last decade childhood obesity has doubled. Trends can now be discerned from both past and present records now that a broad common definition of obesity has been agreed, but use of body mass index is unreliable for children because early fatness reduces with age, although careful interpretation can yield information. Yet southern European countries (such as Spain, Italy and Greece) show obesity levels much higher than those of middle or northern Europe and their causes may be either genetic or lifestyle difference or a mix, of course. If obesity problems are to be solved we must find the relevant factors, which is not easy.

Problems for obese children involve teasing, clothes, etc. and low self-esteem. Sometimes low self-esteem prior to obesity causes children to isolate themselves and eat overmuch for consolation, which promotes obesity and adds to their anxieties, which in turn causes under-achievement and often serious social problems. While appearing generally well, obese children are now under scrutiny for medical implications. Type Two Diabetes, which occurs in overweight adults, is now found in adolescents (particularly in America but now also in Britain). Although the condition may be improved if fat is removed, the implications are quite serious.

The remedy is not so simple as making people eat less, which certainly helps, but people’s needs vary for the same size, weight and activity according to their genetic variations. It is not easy to discover what is being eaten or what is needed for particular individuals. Overweight people need more energy to sustain their activities, so they tend to eat more than others do anyway. On average the population tends to eat less than it did 30/40 years ago and surveys of children show that overall they are consuming fewer calories than before. Thus overeating cannot be easily matched to obesity. Further, genetic differences alone cannot account for obesity, since that stable background underlies obesity growth.

We must consider environmental issues. Eating patterns have changed. Prepackaged foods have complex origins, but they tend to be high in calories and low in micronutrients, minerals and fibre, so much more may be eaten in order to be satisfied. Food variety is now greater than before – for example, of crisps, so that people tend to eat more of them. Television promotions affect consumption patterns. Much soft food is now consumed, which requires less chewing than used to be the case, and vegetables, fruit and harder foods are now less favoured than before. Much food is produced for rapid and effortless consumption, which probably causes more food to be consumed than is needed. Formerly family meals involved patience and socialization, whereas today casual mushy meals whilst watching television do not provide the delays that assist satisfaction. Easy availability and low cost, coupled with a lack of real hunger in much of our society, also encourages eating at will. People have become less aware of what they are effortlessly eating and they lack the indicators of earlier times of when they should stop.

Such factors are not easily studied, but in the speaker’s experience fat children are often ‘faddy children’, who avoid vegetables, fruit, meat (except in hamburgers) and do not have whole-wheat bread (with its fibre content). In 1997 a national survey of 4 to 18 year olds showed that over a week 50% ate no citrus fruit or leafy vegetables, despite its availability. Recommended diets do include starchy foods (such as cereals) which would provide for half of energy needs and are preferable to fat, but they are usually refined and have sugar, fat and other ingredients added.

Dieting for girls of 15 to 18 years can be dangerous, so any discussion of obesity can be seen as undesirable, since anorexia has a high mortality rate (largely through malnutrition and infection). In practice, very few obese children become anorexic and the real risk is that normal children will see themselves as ‘fat’. Many dieters eat fattening foods, which they do not regard as foods, outside their diets. Items such as crisps and snacks are not seen as food by those children on their way to and from school who have missed breakfast.

In the 1997 survey, 36% of 11 to 15 year olds reported that ‘good cooking’ consisted in making sandwiches, 31% in making toast. In Britain today many either have never learned to cook or cannot be bothered to cook, losing therefore the ability to know and control what goes into food. Despite the many cooking programmes on television, many people confess that they do not know how to cook, possibly because most of the programmes do not deal with everyday cooking situations. Deep-frying and the making of toast and sandwiches, appear to be favoured forms of cooking within the least well-educated sections of the community.

Achievement of a balance between what is needed and what is consumed must relate to our basic metabolic rate, to environmental factors, to activity rates and to aspects of growth in children. Apart from the first six months of life, growth takes a low proportion of energy consumption – most goes on activities. There is little evidence that obese people are less active than other people. Many adolescents are relatively inactive anyway today, obese or not. The obese need more energy to move their greater weight when they are active, it may be observed. Today there is less walking and cycling to school than hitherto, no doubt for good reasons. There are fewer play spaces. Television sets keep children in warmer, less infectious homes than in the past. Overall then it is difficult to differentiate between various environmental factors, although evidence in the U.S. and Mexico clearly shows that the more adolescent boys in particular watch television the fatter they become – some even fall below the basic metabolic rate into clinical coma! The speaker remarked that a small amount of vigourous physical activity in a day may not outweigh the many indolent hours of that day. Our increasingly sedentary lives may be a major factor in the increase of obesity. People now use escalators rather than stairs, labour-saving devices in kitchens and gardens, and mechanical transport.

Apart from the general discomfort caused by being overlarge for common facilities, obesity makes other conditions such as orthopedic, coronary, diabetic and blood pressure problems much worse. What may be done about this serious situation? We should all be considering making sustainable lifetime changes in lifestyles.. Realistically, improvements will take time – rapid dramatic change is unlikely. People should not see obesity as a joke nor that change is impossible. Although school occupies much time outside family life we can urge the use of stairs, get children to help around the house, to go by bus or walk to school and to take part in sports and leisure activities which help to relieve the boredom which leads to casual eating. Although children’s dislike of eating vegetables is now recognized as a global trend, not only children but also parents and teachers need education in nutrition and to be active themselves as role models. There are now many organizations and policies to support such actions and school meals are being reformed. Diet control can be achieved by changing content rather than by omissions and by educating for understanding the purpose of such controls. While many adolescents care for the ‘environment’ in general, more need to become aware of their responsibilities with respect to their own health and that of society, while still having the freedom to decide their own lifestyles. Responsibilities stretch more widely of course – while advertising, food presentation and peer pressures tend to set up habits, public concern can be expressed through homes, schools, communities and even industries and governments. Global agencies can influence global industries. Dr Poskitt concluded by repeating Habitat Twos’ statement that ‘ The wellbeing of children is a critical indicator of the health of society’.

In response to questions she stated that while research is unclear it is possible that fibre in wholemeal bread delays absorption, which may affect hormonal responses, which in turn affect the production of fat. Although genetic backgrounds may help determine metabolic rates, types and amounts of food intake can differ widely, whatever the rate may be, so producing variations of fatness. Metabolism – the ‘speed with which you use up your energy’ – may be controlled by genes, but we cannot tell at present. There is now much research on the effects of nutrition on foetus and embryo genetics and it seems clear that early growth impairment inhibits growth through life, but her early studies of fat babies showed that by early childhood most became normal in weight. Because childhood feeding habits have changed there is now rising concern, but she believes that such concern is less justified for obesity than for other diseases. Babies today are less fat than they were thirty or so years ago.

When it was suggested that because education is ineffective fat control should be achieved by ‘drugs and dietary coercion’, Dr Poskitt replied that today there is general concern about lifestyles, particularly of the ‘socially disadvantaged’ – urban dwellers with unfulfilling lives who might be persuaded to ‘see their lives in a different way’. Public health can be improved only slowly and legislation must await general acceptance, as with cigarettes and seat belts. The concern is not just about obesity and there are dilemmas – the need for rapid transport must be set against pollution issues, for example – but ‘people must be given power over themselves’ so that they may achieve ‘more worthwhile lifestyles’. Many slimmers get bored and give up, but they can be encouraged to persist to avoid recognized disadvantages. All we can practically do, perhaps, is to ‘raise awareness’.

Geoffrey Catchpole