One in six of us may carry an ‘obesity gene’ that experts say makes us more likely to be overweight, but can we really blame mum and dad?
British scientists found that people with two copies of the FTO gene are 70% more likely to be carrying too much weight. In fact, people with this genetic make-up weigh an average of 3kg more than those with no copies of the gene.
Researchers from the Peninsula Medical School and the University of Oxford studied data from 40,000 people. They estimated that as many as one in six people could be carrying two copies of the gene, while half of all white Europeans are thought to carry one copy of the gene.
“We are eating more but doing less exercise and so the average weight is increasing. But, within the population, some people seem to put on more weight than others,” Professor Andrew Hattersley, from the Peninsula Medical School, said.
“Our findings suggest a possible answer to someone who might ask ‘I eat the same and do as much exercise as my friend next door, so why am I fatter?’ There is clearly a component to obesity that is genetic.”
Wave a white flag to weight loss?
You may feel like giving up if you’ve got a hunch about your DNA, but can we simply blame mum and dad if we don’t like what we see in the mirror? Unfortunately, the answer is no.
That’s because having the FTO gene only makes you more likely to be overweight if you eat a high-fat diet and you don’t exercise.
The truth is our food habits have a much greater impact than DNA when it comes to body shape. If you keep the calories down and make exercise part of your routine, you can overcome your genetic make-up.
A study by the Lund University Diabetes Centre found exactly that: even if you were unlucky in the genetics game, the critical factor is still what you eat.
Using data from 230,000 people, researchers discovered that those with the gene had a far greater chance of being overweight, but only if their usual food habits were high in fat. Those people whose diets were low in fat were no more likely to be overweight, despite the inherited risk, the study found.
“This shows that we are not slaves to our genes,” author of the study Emily Sonestedt said. “Even if we are born with an inherited predisposition to obesity, lifestyle is more important.”
The FTO gene affects the part of the brain that regulates appetite and tells you when you’re full. So, it could be that people with the gene don’t feel as full from eating fat as those without it. It's possible, therefore, that we consume more and gain weight, Sonestedt suggested.
Boutique dieting
It may be outrageously expensive, but it is possible to create a personalised diet based on a person’s DNA.
Researchers in America gave 138 women a cheek swab to determine their genetic profile. The women were then put onto a bespoke diet that suited their DNA, for example low-fat or low-carbohydrate diets.
Those on the ‘correct’ diet for their genes lost two to three times more weight than those on the ‘wrong’ diet, the study found.
The results show that the technology may have potential, but there’s a lot more research to be done before it starts changing the way we lose weight.
The way forward
While some people may be genetically predisposed to gaining weight, there is no genetic reason why we all can’t be somewhere in the healthy weight range, said Dr Clare Collins, Accredited Practicing Dietitian to The Biggest Loser contestants.
“People who make excuses aren’t successful,” she said. “The trick is to put the healthiest habits that you can live with on a long-term basis into practice and a healthy weight will find you.”
The good news is that the research on how to lose weight is tried and tested. No matter what your genetic profile, if you reduce your total daily calorie intake from the level you consume now you will find that you lose some weight.
To lose 0.5–1kg a week, for example, you need to reduce your calories by 500 to 1,000 a day. That means cutting out 3,500 to 7,000 calories a week. This is because one kilogram of body weight on the scales contains roughly 700g of actual fat. Each gram of fat is worth 10 calories.
Controlling your portion sizes, eating lots of fruits and vegetables, cutting down on alcohol, switching to low-fat dairy, only using lean meats, drinking lots of water and being more active are sure-fire ways to reduce your calorie intake, no matter what genes mum and dad gave you.