FTO: Obesity gene makes fatty foods more tempting and alters levels of hunger hormone ghrelin

Jul 15, 2013

An international group of scientists have solved the mystery of a genetic flaw which greatly increases the risk of obesity in one in six people.

A version of an obesity gene, called FTO, had been linked to a bigger belly, but the reason why was uncertain.

A study, published in The Journal of Clinical Investigation, showed FTO gene made fatty foods more tempting and altered levels of the hunger hormone, ghrelin.

Obesity experts said drugs targeting ghrelin might reduce weight gain.

There is a strong family link with obesity, and a person’s genetic code is thought to play a major role in the risk of them becoming overweight.

People have two copies of the FTO gene – one from each parent – and each copy comes in a high and a low-risk form. Those with two-high risk copies of the FTO gene are thought to be 70% more likely to become obese than those with low-risk genes.

But no-one knew why.

FTO gene made fatty foods more tempting and altered levels of the hunger hormone, ghrelin

A team, led by researchers at University College London, tested two groups of men. All were a normal weight, but one group had the high-risk FTO genes and the other was low risk.

The first tests looked at levels of the hormone ghrelin either side of a meal in 10 men from each group.

Levels of the hormone, which makes people hungry, did not fall as far in the high-risk patients after the meal. Their ghrelin levels also began to climb more quickly.

In separate tests, a series of brain scans after a meal showed further differences between the two groups. Men with the high-risk genes found pictures of high-fat foods more appealing than the low-risk men.

Dr. Rachel Batterham, the head of the centre for obesity research at University College London, said: “Their brain is set up to be particularly interested in anything to do with high-calorie food.”

She said they were “biologically programmed to eat more”.

Dr. Rachel Batterham said understanding how FTO affected the odds of becoming overweight would help patients.

She said exercise such as cycling was an excellent way to lower ghrelin levels and there was a significant amount of research from pharmaceutical companies working on the hormone.

Dr. Rachel Batterham added: “Also protein meals do lower ghrelin more, so anything that suppresses ghrelin is more likely to be effective in FTO patients.”

The FTO mutations were probably life-saving at one point in human history when piling on the pounds in the summer would help people survive the winter.

Mothers over-feed obese toddlers because they can’t see that they are already fat

Health

Dec 29, 2012

A new research suggests that mothers are over-feeding their children because they are unable to see if they are too chubby.

A survey of nearly 300 mothers found they struggled to judge the weight of their own toddlers.

Experts say this blind spot can lead to the youngsters being encouraged to overeat, predisposing them to obesity in later life.

The study was carried out by dietitian Rebecca Byrne who asked 276 mothers to describe their 12 to 16 month old toddlers as either underweight, normal weight or overweight.

The researchers then measured the children’s heights and weights.

Rebecca Byrne said the mothers thought 27 of the children were too thin, but only one of these toddlers was actually underweight, with the rest a normal size.

Additionally, while 32% of the toddlers in the study were actually overweight, only four per cent (12 of the 276 toddlers) were perceived as too heavy by their mothers.

A new research suggests that mothers are over-feeding their children because they are unable to see if they are too chubby

Rebecca Byrne, of the Queensland University of Technology in Australia, said: “Mums are often worried their babies and toddlers aren’t eating enough.

“We put a lot of emphasis on weight gain in babies and toddlers as a measure of them doing well.

“I think the perception in our society is that a chubby baby is a healthy baby and the chubbiness is something they’ll grow out of – but they don’t.

“This sticks with them throughout childhood and they often end up overweight as an adult.”

She added: “Mums who are worried their child is not gaining enough weight, may pressure them to eat more or bribe them with dessert or treats.

“This can teach children to ignore their own cues of hunger and fullness, inadvertently promoting overeating.”

Rapid early weight gain before two years of age is associated with a two to threefold increase in the risk of obesity later in life.

Rebecca Byrne said parents are not given the support they need to understand normal child growth and how to pick up weight problems in their children.

She said: “Serious prevention efforts need to start early in life to reverse the trend of increasing childhood obesity and set kids up for life-long good health.”