EU study to look at genetic causes of obesity

The European Commission has launched a new €14.5 million project to find out how diet and genetic factors combine to cause obesity. The DiOGenes project, to be carried out by 30 organisations from 15 countries, will involve collecting DNA from over 13,000 Europeans. It will apparently be 'the most comprehensive study yet of dietary components and the genetic and behavioural factors influencing weight gain'.

The project will include a long-term dietary intervention study in eight countries, to include families with both obese and normal weight individuals. The consortium hopes it will be able to develop a way of predicting an individual's weight change depending on what food they eat, which in turn will lead to personalised diet treatments. The DiOGenes project is being funded under the Food quality and safety priority of the EU (European Union) Sixth Framework Programme (FP6).

Meanwhile, a new US study suggests that about 50 per cent of weight gain in adulthood is down to a person's genes. Researchers at the Saint Louis University School of Public Health studied nearly 4000 sets of male twins who served in the Vietnam War. During early adulthood in the late 1960s, more than 75 per cent were of normal weight, but twenty years later, more than 55 per cent were overweight or obese.

The scientists found that genes accounted for about 50 per cent of the change in the men's body mass index (BMI: your body weight in kilograms divided by the square of your height in metres). Not surprisingly, exercise and diet are amongst the factors that influence the other 50 per cent.

Scientists have studied twins for many years, in order to measure the influence of genes and environment on a wide range of traits. They compare identical twins, who have identical genes and similar backgrounds, with non-identical twins - who also share similar backgrounds, but are no more genetically alike than ordinary siblings. In this way, researchers can estimate how much of the variation seen for a particular characteristic is accounted for by genes.

Study leader James Romeis thinks that the latest study helps explain why some people find it more difficult to lose weight than others. 'We're not acknowledging the strength of genetic factors in our weight-loss strategies', he said, adding that treatments and public health interventions need to recognise the magnitude of genetic factors if short term and long-term interventions are to be effective'. The results appear in the journal Twin Research.