Is it your fate to be fat? Look at your parents

Genes make it harder to shift pounds

IF you want to know how fat you will be in 20 years’ time, the best way is to look at your parents.

Scots researchers say obesity is up to 75 per cent inherited through our genes – and those with overweight parents are far more likely to end up the same way.

It is well known that parents can pass on their poor eating habits to their children, creating households in which every member of the family is overweight.

But now experts studying the causes of obesity say some families will find it harder to shift the pounds, no matter how hard they try – because of the genes they share.

Professor Gareth Leng, professor of experimental physiology at Edinburgh University, said: ‘Parents find their children try to blame most things on them.

‘But studies agree the best predictor of how fat you are and are going to be is how fat your parents were. Each of us is born with a natural weight we are most likely to be, which is genetically predetermined. That is why identical twins, even when raised separately, tend to be very close in body weight.

‘People can try to change that through diet and exercise, but for those with certain genes it can be more difficult.’

One of the most significant genes we are born with is the leptin gene, which helps stop us from getting fat.

Leptin is a hormone produced by body fat, which travels to the appetite control centre in the brain – the hypothalamus.

If you are low on fat, a lack of leptin makes you feel hungry, while if you are storing lots of fat, a surge of the hormone leaves you without an appetite.

Passed on by parents, the leptin gene affects the rate at which leptin is made. Those who get less of the hormone are in danger of continuing to eat even after they are full.

Last year, scientists at Aberdeen University also discovered a ‘couch potato’ mutation that affects the brain’s ‘reward pathway’ linked to physical activity, which could make some people lazier than others.

The researchers have also discovered a ‘fat gene’ known as FTO which drives the body to crave more food and makes resistance to the temptation ‘almost impossible’.

Genes can even affect the amount of ‘ brown fat’ in the body, which is used to burn off energy. This fat, which helps get rid of the calories the body doesn’t need, plays a crucial role in keeping people slim.

Professor Julian Mercer, leader of obesity and metabolic health at Aberdeen University’s Rowett Institute f or Nutrition and Health, said: ‘There may be up to 100 genes which all make a small contribution to predispose someone to put on weight.

‘That has always been the case but 70 years ago, for example, obesity was relatively uncommon. Now we have the kind of environment where people no longer usually have physically demanding jobs, they have cars and often eat badly and to excess, so the consequences of having these genes are being brought to the fore.

‘However, even though most people understand that genes are probably important, that doesn’t mean the situation is hopeless.

‘They can look at their parents to see how they might look, and that they might be genetically predisposed to put on weight, but they must look at how their lifestyle is making that happen.’

‘Predisposed to put on weight’