Obesity is linked to a number of life-threatening chronic diseases including Type 2 diabetes, cardiovascular disease, hypertension, gall bladder disease and cancer. Other associated problems include osteoarthritis and other hormonal and metabolic disturbances, as well as psychological consequences such as depression. Obese people also have to contend with discrimination due to negative stereotypes and attitudes to obesity, particularly in Western cultures.

Obesity is already a major public health problem in industrialised countries, and is becoming more prevalent in the developing world.

How do you measure obesity? The World Health Organisation (WHO) classifies obesity into grades of body mass index (BMI) according to the degree of risk to health. For a given height there is a desirable weight range which is thought to be optimal for health and longevity.

The WHO grades aim to help physicians predict subsequent illness and/or premature death due to obesity. Thus a BMI of between 18.5 and 24.9 for a young adult is associated with the lowest mortality rate, while a BMI greater than 40 poses the most serious health risk (1).

The medical risks from obesity are particularly pronounced if excess fat is distributed around the middle of the body and around the internal organs. Thus the health risks may not be as great if the excess fat is distributed on the hips and femoral parts of the body (i.e. a ‘gynoid’ pattern or ‘pear’ shape) than if it is on the upper body and abdomen (i.e. an ‘android’ pattern or ‘apple’ shape).

Besides BMI, the waist:hip ratio (WHR) is another commonly used measure. A patient’s WHR is obtained by dividing the waist circumference by the hip circumference. Patients with a high WHR (greater than 1.0 in men and 0.85 in women) (2) have more fat distributed abdominally and are at a greater health risk.

Why do people become obese? Obesity is an energy imbalance disorder which occurs when a person’s energy intake exceeds their energy expenditure over a considerable period of time. This energy imbalance promotes an increase in energy which is stored as fat.

A person’s energy balance changes constantly between meals and from day-to-day. Many people believe that weight regulation is a conscious thing. This is not the case. A complex system of physiological mechanisms act within the body to maintain weight within a narrow range appropriate for the individual. Signals conveying information on the flow of nutrients into the body and the current status of storage reserves are sent to the brain from the various tissues in the body. The brain interprets the signals and stimulates changes in eating, physical activity and metabolic rate to ensure that the body’s energy stores are maintained. However, this internal regulatory system can be influenced by many different factors.

The nutrient composition of the diet is important in determining the amount of energy that is consumed and ultimately stored by the body. For example, dietary fat contains more calories per gramme than protein or carbohydrate, and is thought to have the lowest capacity to satisfy hunger and trigger the physiological process which stops an individual from eating more than the body needs to satisfy its energy requirements (3). Therefore, a diet which is high in fat can promote an over-consumption of food and consequently excessive energy intake.

Dietary composition also has an effect on how much of the energy taken in as food is stored. Fat is far more readily stored than either protein or carbohydrate. Furthermore, the body has a virtually limitless capacity to store excess fat compared to protein and carbohydrate, which can only be stored in small amounts.

Daily eating patterns can also influence the amount of food eaten. Missing breakfast, snacking, and eating to compensate for stress all tend to promote over-eating and therefore obesity.

Physical activity patterns have a significant influence on the regulation of body weight. The contribution of genetic factors to the development of obesity is an area which is currently undergoing research. There are now more than 20 genes which are thought to be linked to the development of obesity. It is thought that these genes exert their effects by increasing an individual’s susceptibility to obesity when exposed to a favourable environment, for example one in which plenty of high fat food is readily available (4,5). This may partly explain why some people seem to be able to eat what they like and not put on weight while others are constantly battling with their weight.

How prevalent is obesity? Obesity is becoming more prevalent worldwide and it is expected that this trend will continue.

In most of Western Europe, obesity levels range between 10% to 25%, while in large parts of the American continent the prevalence figures are between 20% to 25%. They can reach up to 40% for women in eastern European and Mediterranean countries, and even higher among some groups, such as black women, in the USA and South Africa.

Levels are particularly high among some ethnic groups such as American Indians, Hispanic Americans, and Pacific Islanders, where the highest rates of obesity in the world are found among Melanesians, Micronesians, and Polynesians. In the urban areas of Western Samoa, 60% of men and 75% of women are obese (6).

- seven new National Obesity Associations have been formed, totaling 30 today;
- International Obesity Task Force was formed;
- The WHO report "Obesity: Preventing and managing the global epidemic" published
- Acceptance of obesity as a disease by other medical specialties
- Impact of pharmacotherapy has started to shape up.

There is a growing need to bridge the gap between primary and secondary care:

- Approximate number of IASO Members = 5000;
- Current estimated number of obese adults = 286 million;
- Estimated number of severely obese by 2025 = 300 million.

We cannot cope alone!!!

Factors being important in helping to bridge the gap between primary and secondary care in obesity management include:

1. Provision of additional resources by Health Authorities;
2. Setting up specialist treatment centres;
3. Development of community-based multidisciplinary teams;
4. Implementation of education programmes;
5. Production and implementation of management guidelines.

IASO - IOTF

The IOTF is campaigning to raise awareness of the global epidemic of obesity and to seek effective government action. ICO'98 is one important milestone in this campaign.

Despite the clear health benefits from sustained moderate weight loss, long-term weight maintenance defeats many obese people. "Obese patients look to the medical profession for help and advice. To date this has largely been in vain", said Dr. Elizabeth Evans, scientific director of Slimming Magazine Clubs. "Doctors are often pessimistic about their ability to manage obesity", she concluded.

Obesity in adolescents is much more likely to persist than obesity in young children, said Professor William Dietz from the Center for Chronic Disease Prevention and Health Promotion in Atlanta. He presented indications for the use of the protein modified fast:

- Weight in excess of 180% of ideal;
- Adolescent; younger if associated morbidity;
- Normal cardiac function;
- Weight maintenance prior to diet;
- Capable of Q2W visits for 5 months.

Clearly, education is necessary, both for patients and doctors. But the experience of an ongoing French study suggests that educating children about diet not only improves their nutritional knowledge, but also can influence the behavior of their parents. Professor Basdevant from Paris concluded that:

- Programme of dietary education improved nutritional knowledge of 6 - 12 yrs schoolchildren;
- This resulted in changes in the dietary habits, mainly a decrease in the consumption of lipid-rich food;
- Effects on body weight evolution remain to be studied;
- The education of the child is associated with changes in the parents' habits;
- Prevention strategies should involve children as active participants.

Professor Vojtech Hainer from the Charles University in Prague explained that the multi-level obesity management network involves national and regional obesity management centres. Within this network GPs are educated to monitor patients' weight and other risk factors and to provide lifestyle advice where appropriate.

(1) World Health Organisation, Geneva 1995. WHO Technical Report Series 854. Physical Status: The use and interpretation of anthropometry. Report of a WHO Expert Committee.

(2) Blundell JE, Green S, Burley V. Carbohydrates and human appetite. American Journal of Clinical Nutrition, 1994; 59(suppl): 728S-734S

(3) Westerterp KR, Meijer GL, Schoffelen A, Janssen EME. Body mass, body composition and sleeping metabolic rate before, during and after exercise training. European Journal of Applied Physiology 1994; 69: 302-8

(4) Sorensen TJA, Price RA, Stunkard AJ, Schlusinger G. Genetics of obesity in adult adoptees. British Medical Journal 1989; 298: 87-90

(5) Bouchard C. Genetics of obesity: overview and research directions, in: The origins and consequences of obesity. Wiley, Chichester 1996 (Ciba Foundation Symposium 201): 108-117

(6) ICO'98 Satellite symposium: Prevention of obesity, Stockholm August 26-28, 1998

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