Why Are Thin People Not Fat? Maybe they have fat chicken virus!

by Lynn Connolly

What a fascinating programme this Horizon investigation was into the question, why are thin people not fat? This show was rather like Claire Sweeney’s Big Fat Diet meets Braniac and it came up with some very interesting scientific facts about fat, obesity and weight gain… or not.

It’s estimated that there are now more people on the planet at risk from obesity-related diseases than there are suffering from starvation. Western society in the 21st century is eating itself into an early grave but, while the ranks of the overweight and obese are swelling, there’s a significant proportion of the population who are apparently immune to this phenomenon.

Are some people really able to eat as much as they want without becoming obese? If so, how do they do it? To find out, ten volunteers – pictured below – agreed to eat double their normal intake of calories over four weeks to see how their bodies coped with a month-long chocolate, cake and fast-food frenzy.

The over eating test was based on a pioneering 1967 experiment on Vermont State Prison inmates, in which medical researcher Ethan Simms recruited a group of prisoners to eat as much as they could until they had gained an extra 25% of their original body weight. Their reward for achieving this was early release but despite eating up to 10,000 calories per day, only six of the nine who took part succeeded.

But why? Why didn’t they all gain huge amounts of weight when some of us only have to look at a doughnut to gain 10lbs?

Well, more than 40 years on from the Vermont experiment, Horizon, with the help of Swedish scientist Fredrik Nystrom from the University of Linkoping, replicated the principles of the experiment with surprising results. While some of the volunteers gained weight and girth, others did not.

Several theories as to why they didn’t were put forward. One of the most surprising possibilities was suggested by one scientist who’s been involved in an investigation into a disease that not only killed chickens wholesale, it made them fat first. He suggested that this virus was infectious and could well have mutated and passed to humans. This meant that not only could a human become fat as a result of contact with a contaminated chicken, they could, in theory, infect other humans too.

Other scientists suggested that a gene is to blame; having the gene makes one more susceptible to being overweight and not having it almost guarantees you won’t be. Likewise, it was suggested that some people simply have no desire to eat more once they are full while others seem to have no ‘off’ switch where the consumption of food is concerned.

All of which was very interesting but of course the danger of blaming fat chicken virus or genes is that it can absolve us of our personal responsibility for controlling our weight and in a society where food has never been more attractively packaged or more readily available, self control – or the lack thereof – still has to be the most important factor in determining our overall weight.

There was also something of a disheartening section of the programme in which a scientist explained that once fat cells reach a certain size, they are then magnets to other fat cells. Worse yet, once those cells reach this critical mass, it’s unlikely they’ll reduce or that we can get rid of them, no matter what we do.

However, what this show didn’t really look at was how come many people can lose huge amounts of weight and keep it off. It really seemed that the scientists were saying, “Well if you’re fat, that’s it, no point trying not to be”

A dangerous observation I think when the fact is, there are lots of things we can do about it, irrespective of genetic propensity or whether a fat chicken ever sneezed on us…


Lynn is an editor and writer here at Unreality TV and is trained psychotherapist and the author of two books. She's addicted to soaps, period drama and reality TV shows such as X Factor, I'm A Celeb and Big Brother.