A GENE linked to obesity makes people eat almost 300 calories – the equivalent of a Danish pastry – extra every day, researchers said yesterday.
A study by scientists in Aberdeen found those with a variant of the FTO gene – first linked to obesity last year – were driven to eat more food. They said the findings could explain why some people found it much harder to control their weight than ot
hers.
The FTO variant was linked to obesity by British researchers, although it was not known how it made people fat. For the latest study, a team from the Rowett Research Institute and Aberdeen University studied 150 people from North-east Scotland.
The group was a normal cross-section of the UK population, aged between 21 and 60. A fifth of them were obese, with 34 per cent overweight.
Their food intake was studied over seven days, with blood samples taken and their fitness and energy-use examined by researchers. Those with the FTO gene variant ate between 120 and 290 more calories per day than those who did not have the "at-risk" variation.
In comparison, the researchers found no link between the variant and energy expenditure or physical fitness.
The two groups were also eating the same kinds of things, with no preference for a particular type of food among those with the genetic variant.
Professor John Speakman, from Aberdeen University, the author of the study, told the journal Obesity: "We have found the first hard evidence linking the 'at risk' variant of the gene with increased food intake in humans.
"Our data clearly suggests that people with this variant of the FTO gene may become fatter because they are driven to consume more food.
"Because this over-consumption may be driven by their genes, it may be far harder for such people to control their intake than people who do not carry 'at risk' variants of food-intake control genes."
He added: "Greater consumption of food does not mean that people are being greedy."
Dr Alex Johnstone, the co-author, who is based at the Rowett Research Institute, said: "There are many factors involved in the development of obesity, and this research suggests that the FTO gene contributes to differential food intake between volunteers."
Studies in mice have also suggested that the FTO gene is expressed in the areas of the brain linked to the regulation of food intake.
Dr Colin Waine, the chairman of the National Obesity Forum, said: "This research sheds light on the reasons why it is hard for people to make and sustain changes in their diet to lose weight.
"There must be millions of people who have successfully lost weight but could not sustain it over the long term.
"The research increases our understanding about why, for some people, keeping the weight off might be more difficult."
Dr Waine said people did not need a lot of extra calories a day to make them overweight.
"Over weeks, months and years, 300 extra calories a day is going to make you balloon," he said.
FACT BOX• Research has found that Scotland comes second only to the United States as the most overweight nation in the world.
• Last year, the NHS bill for prescriptions to treat obesity in Scotland rose by £770,000 to £4.89 million.
• It is estimated that being overweight or obese accounts for about 6,000 cases of cancer a year in women in the UK.
• Some 25.5 per cent of adult Scots have a body mass index (BMI) rating of 30 or over – making them obese.
• One in five children in Primary 7 has also been estimated to be obese.
• Obesity could be costing Scotland as much as £171 million a year.
• The main causes of obesity include the sedentary lifestyle of Scots and a preference for fatty, high-calorie foods.
The full article contains 657 words and appears in The Scotsman newspaper.
