Science - February 2, 2006

Obesity caused by viruses?

Certain viruses can cause obesity, the Sunday Times reported this week. Researchers at the University of Wisconsin found surprisingly high concentrations of the Adeno virus 36 among overweight people compared to thin people. Chickens infected with a similar virus also developed a higher body weight than those without the virus. According to the leader of the research, Dr Leah Whigham, people battling obesity have to not only watch what they eat and get more exercise, but they also have to wash their hands to prevent infection. Time for a new approach to fighting obesity?

Professor Martijn Katan of human nutrition:
‘It looks to me like the umpteenth attempt to find a complicated explanation for a problem that already has a simple explanation. People are overweight because they take in more calories than they burn. This research finds a relation with certain viruses. It all looks very impressive, but who says those viruses are the cause of the higher body weight? Maybe overweight people have more chance of becoming infected with such a virus. Do you know the ‘Ockham’s razor’ principle? It says Pluralitas non est ponenda sine necessitate. In other words, don’t think up more explanations if they’re not necessary. This is one of those cases.

‘These researchers say that the increased rate of obesity is difficult to explain based only on changing eating patterns and less exercise, but I don’t see any basis for this. You don’t have to eat way too much and remain motionless to gain twenty kilos. As long as you wait long enough. For most people it takes twenty years. That’s one kilo per year, or three grams of fat per day. You often hear overweight people saying that they don’t eat very much. But people don’t get fat from thin air. It’s an image that they have created, and it is caused by the inhuman pressure put on them to be thin. They use this image to defend themselves against the way they are treated by others.

‘And yet, the whole world is busy trying to think up ingenious mechanisms for obesity. The simple message of ‘too much food’ doesn’t earn anyone any money. Molecular biologists are busy looking for genes that cause obesity. But while the number of overweight people has doubled in the past thirty years, our genes have not changed. This kind of research is clouding the embarrassing truth that too much food is the cause for obesity. Let’s stop looking for all kinds of fancy explanations for why people are overweight and focus our research on finding a solution. Someone recently suggested increasing the price of chips. Go and study whether simple steps like that will really work. Do measures like improving bike lanes and adding more gym classes at primary school really help?

‘That obesity could be passed on through a virus infection sounds like an urban myth to me. Will we see these researchers receiving the Nobel prize in twenty years? I don’t think so!’

Jasper Harms

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