Scientists have found a common cold virus which can interfere with our body's normal functioning and make us fat. The highly infectious virus is known as AD-36, infects the lungs and along with causing sore throats forces fat cells to multiply.
Nikhil Dhurandhar, an associate professor at The Pennington Biomedical Research Center, in Baton Rouge, Louisiana has conducted animal and human studies on the virus Adenovirus-36 or AD-36 for more than ten years.
His team took blood samples of more than a 1000 patients from an obesity clinic and they tested the blood for AD-36 virus. They found that 20% of the patients had had a brush with the virus at some stage or another and were significantly heavier than those who tested negative for the virus.
"When this virus goes to fat tissue it replicates, making more copies of itself and in the process increases the number of new fat cells, which may explain why the fat tissue expands and why people get fat when they are infected with this virus," Dhurandhar said.
In another test they found that a third of the obese people had the rare and highly contagious virus compared to just 11 % of thinner people. They also noted that even amongst the non obese group, those with the virus were heavier than average and the resultant weight gain can last three months until the body has built up resistance to the bug.
New research supports earlier theories from studies on weight gain and shows the bug could cause overweight people to gain weight. "People could be fat for reasons other than viral infections, so it's pointless for fat people to try to avoid infection," said Dhurandhar.
Dr Carel Le Roux, an obesity expert at Imperial College, said, "It's very important to know that it's not the reason why we're seeing a major epidemic of obesity. Dr Roux has been carrying out experiments to see if he can make thin people fat. "It may be a small contributing factor and we need to explore all the avenues because so many people need help and we're just not clever enough to help them at the moment."
Dr Tam Fry, chair of the Child Growth Foundation, said, "I'm skeptical because this theory has been around for 10 years and no-one has come up with a comparable study to back this up.
"Concern over the obesity epidemic seems to be throwing up a whole load of off-the-wall ideas but the message remains the same, that sensible eating and exercise are the major components to get your weight under control." (Harkiran contributed to this story)