Scientists have found the most important obesity gene which could possibly be targeted by drugs to fight the increasingly deadly obesity epidemic.

According to the researchers, mice bred without the gene known as IRX3 were nearly a third lighter than mice with the gene. The equivalent gene is also found in humans and its function may explain how people are more vulnerable to obesity than others.

Their findings suggested the IRX3 can control body mass and composition. Marcelo Nobrega, a researcher from the University of Chicago and lead scientist of the study, said the data suggest the IRX3 gene helps regulate metabolism.

The discovery of the most important obesity gene can provide researchers long confounded by the genetics of girth.

Low-fat Diet to Curb Obesity and Heart Disease

The benefits of following a low-fat diet do not reduce the risk of heart disease, according to a leading scientist.

James DiNicolantonio, a New York-based cardiovascular research scientist, said the current dietary advice given by nutritionists was based on a "flawed" study from the 1950s.

He added the popular fear of saturated fat increasing cholesterol has no basis. Health experts have long believed a low-fat diet can help prevent diabetes and obesity.

Evidence in various studies has shown that a low-carbohydrate diet can improve cholesterol as opposed to a low-fat diet. DiNicolantonio still believes people should avoid eating processed food.

The World Health Organization (WHO) believed obesity rates almost doubled worldwide from 1980 to 2008.

In a previous report, WHO has cited New Zealand as one of the worst countries with increasing obesity rates and fast food consumption in the world.

According to WHO's study about fast food purchases per capita, New Zealand ranks fourth out of 25 countries based on purchases which lead to more people being obese.