The jab that’s almost as good as a gastric bypass

Gluttony. the word conjures up the image of the grotesque Mr Creosote from Monty Python’s the Meaning of life, just before he accepts that final ‘wafer-thin mint’ — and suffers the explosive consequence.

unfortunately, this is a caricature of how most of society thinks of obese people. Gluttony, greed and slothfulness form a trinity of ‘deadly’ sins that could, in theory, condemn you to eternal damnation and which are associated with the obese.

the seven deadly sins are a religious edict from the 4th century, but today, with an estimated 1.4 billion people worldwide classified as obese, it seems we have all become sinners.

But are obese people, as is commonly assumed, simply gluttonous beings?

I have been studying the genes linked to obesity for nearly 20 years and whenever people hear what I do, they all say the same thing: ‘you’re just giving fat people an excuse!’

let’s be clear: the increase in obesity over the past 30 years has, undeniably, been down to changes in lifestyle and food availability. Put simply, we eat too much and move too little. It is physics.

Gene research shows, however, that some people eat more than others because they feel a little more hungry all of the time.

thin people, therefore, are not morally superior beings able to say ‘no’ to temptation; they just feel less hungry.

Equally, obese people are not slothful, lazy or bad; they are merely fighting their genes.

I recently spent a couple of months making a documentary for BBC Horizon during which I met obese people and the doctors and scientists trying to understand and treat obesity. I met a group of dieters in Colchester with a higher genetic risk of obesity because they carry one or two copies of the Fto (fat mass and obesity related) gene.

one copy can be inherited from each parent. Having high- risk versions of the Fto gene makes people prefer foods higher in fat and sugar and want to eat more.

Dr tony Goldstone, from Imperial College london, conducted a small experiment in front of the cameras and found that, at least in the short term, dieters told they had two copies of the high-risk Fto gene altered their behaviour by picking, when given a high or low-fat food choice, the lower-calorie option.

Fto is just one of more than 100 genes we know to be linked to obesity. However, as our experiment highlighted, just because you have a higher genetic risk of obesity does not mean that you will become obese — it is all about doing the very best that you can with the genes you have been given.

I also met a man who had undergone gastric bypass surgery and saw the dramatic effects first hand, both in terms of his huge reduction in appetite and in his spectacular weight loss.

We now know that while gastric bypass reduces the absorption of some nutrients, the key reason for patients’ change in appetite is hormonal; because food is delivered farther down the gut in a form not normally seen, the gut responds by releasing a different mix of hormones, which then trick your brain into thinking you are full.

Clearly, rolling out gastric surgery to all obese people is unrealistic. What happens, however, if you can mimic the effects of a gastric bypass without the actual surgery?

Scientists at Imperial College london did this exact experiment with a hormone injection — and it appears it can indeed mimic gastric bypass and make the brain think you are full, so patients actually ate less; around 30 per cent less in a meal.

there are hurdles though, the biggest of which is finding a way to make the hormone injection more long-lasting; at the moment, you have to inject the hormones before every meal.

NEVERTHELESS, these results are very exciting and represent significant progress in obesity therapeutics. So, returning to my original question; with regard to our love of eating, have we all become sinners?

It is crucial to remember that the drive to eat is one of three ancient and primal instincts (the others being to avoid dying in a hideous fashion and to reproduce) that promote survival.

It has been shaped by millions of years of evolution and has provided living creatures with powerful and redundant mechanisms to adapt to times of nutrient scarcity.

to be overweight in this current environment of food abundance, therefore, is not ‘sinful’, but is a natural survival response and one that even suggests you are actually more highly evolved.

As we strive to tackle one of the greatest public health challenges of the 21st century, to deny the central role that our genes have played is unhelpful.

our genes are like a hand in a game of poker — you cannot control if you are dealt a good or a bad hand, yet you can win or lose with either, depending on exactly how you play your hand.

DR YEO is director of genomics at the Medical Research Council’s Metabolic Diseases Unit at the University of Cambridge. HORIZON: Why Are We Getting So Fat?, BBC2, 9pm, tonight.