Some of the world’s top scientists have got together to try to reduce the growing number of people who are dangerously fat. In Britain one in five women and one in seven men are obese – and those figures are growing fast. But we are still behind the States where over half the population are grossly overweight. Scientists from the University of Aberdeen, Rowett Research Institute and Grampian University Hospitals NHS Trust have formed ACERO, the Aberdeen Centre for Energy Regulation and Obesity.
The group will study the condition and related phenomena in the hope of coming up with a solution. Professor of Zoology at Aberdeen University and founding chairman of ACERO, John Speakman said: “It is clear that the failure of some people to regulate their body weight is not just a matter of people overeating or being lazy. “It is also a problem with their physiology which might have many causes. This new group of scientists collaborating across institutional boundaries is set to make a significant impact on our understanding of this problem, leading to breakthroughs which will aid in its treatment.
Professor Speakman said animal metabolisms could give a clue on how to tackle human obesity. He said: “Many small animals change body fatness in response to day length changes. “If we can find out why this happens, then we might be able to evaluate the sorts of physiological problems that might underpin difficulties which obese people have in regulating their body weight. “One popular idea is the `thrifty genotype’ hypothesis which suggests the people who are prone to obesity have been favoured by natural selection in the past because they are efficient in storing fat.
“It is only when faced with a Western diet high in fat that the `thrifty genes’ start to cause problems because they are too efficient and lead to massive increases in body weight.” Obesity is associated with increases in Type II diabetes, high blood pressure, cardiovascular disease and other disorders. As a result, it has considerable public health significance as well as economic repercussions. In 1997 the World Health Organisation officially declared obesity to be one of the most serious
health problems facing mankind.
Obesity is probably the oldest metabolic disturbance; an obese Stone Age statue has been unearthed. Similar evidence of obesity is found in Egyptian mummies and in Greek sculpture. People in a society become obese as soon as enough food and leisure are available to cause an imbalance between energy intake and energy expenditure. Sustained caloric imbalance with consequent obesity is becoming the behavioral norm of the American population. Forty million adult Americans weigh more than 20% above their desirable weight. Its prevalence is increasing in all major race/sex groups including younger adults age 25 to 44.
This increase in the prevalence of obesity is against the trend in the last few decades toward lower dietary fat and cholesterol intake, increased exercise, decreased cigarette smoking and increased treatmenthypertension. Obesity is, therefore,
Obesity has multiple causes; the development of obesity is a complex interaction between genetic, psychological,socioeconomic and cultural factors. Americans with less education and income are, on the average, more obese. Individuals have unique genetic and environmental factors which affect how food is processed; there are, therefore, individual differencesin susceptibility to obesity.
In the past, obesity has often been measured by “desirable” or “relative” weight. Life insurance tables of desirable weight are based on weights associated with the lowest mortality, among the insured population, who are predominantly upper middle class Caucasian individuals. Relative weight is calculated by dividing the patient’s weight by a standard weight that is based on the patient’s height, age and sex. There are several problems with the appropriateness of these two measures. They are not applicable to the entire population. They do not reflect current weight or mortality relationships in the American population. Frame size is subjectively determined. They do not provide data predicting the longevity of young persons weighed in their early 20s and followed until their death.
A newer, more clinically useful measure of overweight, is the so-called Body Mass Index (BMI). The BMI is obtained by dividing the weight in kilograms by height measured in meters, squared (W/H2). Identical standard values can be used for all adult patients, both men and women. The lowest morbidity and mortality, for both sexes occur in persons with a BMI of 22-25 kg/m2. Life insurance and other epidemiological studies have suggested that mortality rates begin to increase substantially at
weights 20% greater than desirable, this corresponds to a BMI of 27 kg/m2. Individuals with a BMI of 30 kg/m2 or greater clearly increased mortality.
All of these indices are only measures of overweight.