Obesity: a medical history

摘要

In the early spring of 1988, Gerald Reaven, Professor of Medicine at Stanford University, was struggling to prepare his Banting Award address for the American Diabetes Association Conference, when ‘the notion of Syndrome X sprung almost full-blown into my mind’ (1). Diseases, once seemingly unconnected, were drawn together under the banner of insulin resistance and presented as one life–threatening syndrome. For the first time, the clustering together of illnesses including heart disease, stroke, diabetes and dyslipidaemia was explained clearly and scientifically. On 1 September 2005, Sony’s state-of-the-art anti-obesity weapon, Aibo the Robotic Dog, was launched in Tokyo. Wirelessly connected to scales, a pedometer and to a personal organizer recording food intake, Aibo has four stages of alertness: jumping and wagging its tail happily, playing ‘funky music’; morose and lying inactive, playing ‘dirges’; and two intermediate stages. The success of the dog’s owner in controlling his own energy balance is reflected in the dog’s mood. Although there have been major advances in the study of obesity, Aibo clearly demonstrates that the one thing the battle against obesity does not need is new scientific invention. Reaven’s utterances proved pivotal, and nothing since has carried the gravitas of his proclamation. Aibo, on the other hand, will be consigned to history’s waste bin. Uniquely among chronic diseases, lack of scientific knowledge is not a barrier to the successful treatment of a person who is obese. Whereas cancer treatment requires new drugs and heart disease updated techniques, obesity is different. We already know enough about the causes and how to manage it by diet, activity, drugs and surgery. The history of obesity is a history of failure. Looking back in time, however, gives us many insights as to treatment in the future. Obesity is changing, but its origins can be traced back 30 000 years, to our prehistoric ancestors. Survival of the fittest dictated that individuals who stored energy in the most efficient way would survive the inevitable fast and famine that would follow times of plenty. This has been attributed to the ‘thrifty gene’ (although no such individual gene exists), ensuring the continued dominance of our hunter–gatherer predecessors. But natural selection has turned on us. Life now favours inefficient phenotypes who fail to store energy in adipose depots, while those who lay down fat in the abdomen are condemned to premature death. To fight obesity, we are flying in the face of evolution and instinct, consciously countermanding the urge to eat for survival, and be as inactive as possible in order to conserve energy. Some 30 000 years ago, prehistoric statuettes, including the famous Venus of Willendorf, depicted anatomically accurate abdominally obese women. The function of these caricatures is hotly debated. They may have been fertility symbols – ironic in view of current knowledge that obesity causes infertility. Alternatively, the images, small enough to be carried round in the palm of the hand, may have been predecessors of Playboy magazine. Moses is considered to be the original writer on diet, recommending to the Jews, ‘bread, wine, milk, honey; quadrupeds that divide the hoof, and chew the cud; all the feathered kind, a few only excepted; and fishes that have fins and scales’. Acceptance of obesity as a medical phenomenon has been slow. For thousands of years, overweight and obesity were exceptional, rarely seen and never studied. In some cultures, indeed, obesity was prized, indicating status and wealth. Only the richest had the means to become obese and girth advertised wealth more effectively than the richest clothing or jewels. The ancient Greeks were the first, however, to realize the dangers of obesity and its association with disease. Hippocrates understood that obesity led to infertility and early death, writing: In the beginning, man made use of the same food with the beasts, and it was