Is it genes or lifestyle?
New research says that fat genes are responsible for a fifth of obesity, which means that diet and exercise might not make much of a difference for some.
The Journal of Nature released the findings and believe that these are the most accurate estimates for the amount of people who are suffering from obesity because of DNA as opposed to lifestyle. It is now thought that obesity might move into the disability category.
This has the power to change the way that the NHS think and treat the condition.
About a quarter of adults and one in ten children are obese in the UK today and £8 billion is spent every year to treat obesity and the health issues that surround it.
The DNA of over 300,000 people was studied worldwide by the Genetic Investigation of Anthropometric Traits consortium.
Elizabeth Speliotes, of the University of Michigan, who led the research, told The Times that the research revealed that there was not just one gene that contributes to obesity.
"The large number of genes make it less likely that one solution to beat obesity will work for all and opens the door to possible ways we could use genetic clues to help defeat obesity," she said.
Alistair Hall, professor of medicine at the University of Leeds, who was involved in data collection for the study, added that exercising and eating healthily were still worth pursuing to try and prevent becoming fat, but the discovery "could help many people born with a disposition to put on too much weight".
Another paper said that women are much more likely than men to have the genetic abnormalities that cause fat to accumulate around the waistline rather than the hips. This puts them at a greater risk of type-2 diabetes and cardiovascular trouble.
From the 20 areas of DNA that are directly attributed to fat distribution, 19 of these have a much more profound effect on women. It is suggested that these differences can be explained by our sex hormones.