According to two major scientific studies, seven new genetic variants make people overweight. All new identified genes are linked to appetite control and obesity. An Icelandic biotechnology company, deCode Genetics, and an international academic consortium conducted the study and published their findings yesterday in the journal Nature Genetics.

Chief executive of decode, Kari Stefansson said, "This suggests that as we work to develop better means of combating obesity, including using these discoveries as the first step in developing new drugs, we need to focus on the regulation of appetite at least as much as on the metabolic factors of how the body uses and stores energy."

In both 'genome-wide association studies', scientists analyzed the DNA samples of more than 100,000 people by using latest DNA-reading technology to associate genetic variations with body mass index-a commonly used measure of obesity. Both studies have shown that genetic factors account for 40-70% of population variation in body mass index.

Every identified genetic variation has a modest effect. Member of the consortium, Mark McCarthy, of Oxford University said, "We are finding that common diseases have complex causes and its only by understanding the biology that we can start to make rational attempts to treat and prevent conditions such as obesity." Dr Cristen Willer, from the University of Michigan in Ann Arbor, US, said, "These discoveries should change people's attitudes to obesity."