Scientists unlock secret to overeating

CANCER RESEARCH UK scientists have found new evidence that the tendency to overeat could be genetic according to research published in the International Journal of Obesity* today.

Researchers from University College London (UCL) who were funded by the Biotechnology and Biological Sciences Research Council created a new experiment to see if eating when full was linked to a gene called FTO**. To do this, they observed the behaviour of 131 four to five year olds who were offered a plate of biscuits after they had eaten a meal.

They found the children who ate more biscuits were more likely to have one or two of the ‘higher’ risk versions of the FTO gene. This research could help pave the way to a better understanding of the processes that lead children to become overweight or obese – one of the biggest risk factors for cancer.

Lead author, Professor Jane Wardle, director of Cancer Research UK’s Health Behaviour Research Centre at UCL, said: “Previous research has shown that the FTO gene is linked to larger body size. We believe this research published today tells us more about how some children are more responsive to signals in their bodies encouraging them to eat when full than others. Knowing how the genes work is the first step to minimising these negative effects.”

“We hope this research will help improve our understanding of the causes of childhood obesity so that better measures can be taken to reduce it. Children with higher risk versions of the gene might be helped if parents do their bit to keep temptations out of the home.”

Professor Wardle continued: “The occasional treat won’t do us any harm – but this study showed that some children don’t know when to stop – which could lead to the onset of obesity and a lifetime of health problems. We know the best way to maintain a healthy body weight is to eat a diet with lots of fibre, vegetables and fruit as well as keeping portion sizes down, and being physically active.”

Research has shown that obesity increases the risk of cancer of the bowel, womb, kidney and post – menopausal breast cancer. In the UK alone, it is estimated that 13,000 people every year could avoid cancer by maintaining a healthy body weight. Obesity has also been linked to increased risk of other cancers including cancer of the gallbladder, oesophagus and pancreas, but more research is needed to confirm this.

In the study published today, the researchers also looked for a genetic connection between the FTO gene and children’s interest in taking exercise, and didn’t find a link.

Sara Hiom, director of health information at Cancer Research UK said: “A genetic propensity to overeating doesn’t doom a child to a lifetime of obesity. But it does allow us to think about how we can best help the children most at risk of becoming obese. An important part of this is to urge parents to provide healthy snack options such as carrot sticks rather than chocolate biscuits and ideally to encourage children to stop eating when full. We calculate that a quarter of all cancer deaths are caused by unhealthy diets and obesity.

“This work attempts to understand what underlying biological processes are involved in eating too much. But it’s important to remember that not all children with these ‘high’ risk genes will over eat – other influences are very important too – including the eating habits of parents and the types of food made available.”

ENDS

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Notes to editors:

J Wardle, C Llewellyn, S Sanderson, R Plomin (2008). The FTO gene and measured food intake in children

About the study

The study was a collaboration between Department of Epidemiology and Public Health, Health Behaviour Research Centre, University College London, London, UK Social and Behavioral Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA and King’s College London, Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, London, UK. It was funded by the Biological Sciences Research Council and Cancer Research UK.

**Participants were from 214 families with twins who agreed to take part. Parents were asked to serve a full meal for their children; then within one hour of them finishing the meal, the children were offered a mixed plate of sweet and savoury biscuits which was weighed before and after the experiment. Using data from one child per family, the results showed that, on average, the children with two copies of the lower-risk FTO alleles ate less than those with one or two of the higher risk alleles. The authors concluded from this that allele is protective against overeating by promoting internal signals of feeling full.

You can find out more about the original survey-based research linking the FTO gene to weight in Science, 2007, Frayling et al. and by reading about an earlier study by Professor Wardle.

Maintaining a healthy body weight

Cancer Research UK advises that individuals help reduce their risk of cancer by taking regular exercises and eating a diet that is low in red and processed meat, low in fat and includes fruit and vegetables as part of a balanced diet in order to maintain a healthy body weight. People can also lower their risk by avoiding alcohol, not smoking and reducing their UV exposure. Read about Cancer Research UK’s top ten tips for maintaining a healthy body weight.

UCL (University College London)

Founded in 1826, UCL was the first English university established after Oxford and Cambridge, the first to admit students regardless of race, class, religion or gender, and the first to provide systematic teaching of law, architecture and medicine. In the government’s most recent Research Assessment Exercise, 59 UCL departments achieved top ratings of 5* and 5, indicating research quality of international excellence. UCL is in the top ten world universities in the 2007 THES-QS World University Rankings, and the third-ranked UK university in the 2008 league table of the top 500 world universities produced by the Shanghai Jiao Tong University. UCL alumni include Marie Stopes, Jonathan Dimbleby, Lord Woolf, Alexander Graham Bell, and members of the band Coldplay.

The Biotechnology and Biological Sciences Research Council (BBSRC)

The Biotechnology and Biological Sciences Research Council (BBSRC) is the UK funding agency for research in the life sciences. Sponsored by Government, BBSRC annually invests around £420 million in a wide range of research that makes a significant contribution to the quality of life for UK citizens and supports a number of important industrial stakeholders including the agriculture, food, chemical, healthcare and pharmaceutical sectors. BBSRC carries out its mission by funding internationally competitive research, providing training in the biosciences, fostering opportunities for knowledge transfer and innovation and promoting interaction with the public and other stakeholders on issues of scientific interest in universities, centres and institutes.

The Babraham Institute, Institute for Animal Health, Institute of Food Research, John Innes Centre and Rothamsted Research are Institutes of BBSRC. The Institutes conduct long-term, mission-oriented research using specialist facilities. They have strong interactions with industry, Government departments and other end-users of their research.

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