Obesity rates have achieved alarming rates worldwide and this is an outset to many research studies in the process of seeking a solution.

A team of scientists from the Karolinska Institute in Sweden has made a study over the reasons why overweight people have difficulties in losing weight and why they regain it in a short time. The results of the research were published online Sunday in the journal Nature.

Apparently, the answer to these old questions is given by the fact that fat cells form wholly until adulthood and they have a constant number during life beginning with this stage.

The Swedish researchers tested several hundred children, teenagers and adults at different ages and analyzed the dynamic of their fat cells. They noticed that the number of children’s adypocites’ grew, while in the case of the persons heading to or reaching maturity it remained the same.

The next step in their study was to analyze people who were about to undergo a diet or a surgery with the purpose of losing weight. They compared the number of cells the subjects had before the process of losing weight and afterwards and they noted that it was unchanged. They stated that each person, irrespective of how thin or fat she/he is, loses about 10% of her/his fat cells and the body replaces them in a short time.

"It explains why it's so difficult to lose weight and to keep it off - those fat cells aren't going anywhere, and they're crying out for more," said Dr Kirsty Spalding, a neurobiologist and lead researcher in this investigation, as quoted by BBC News.

Seemingly, the level of overweight is caused by how much the cells shrink or bulge.

Specialists who have worked on finding answers to the annoying queries related to controlling obesity deem this new discovery is of great significance in their following work on the matter. Still, there are doctors who take the finding for just an interesting one, with no possibility of using it anyhow, as they consider this mechanism of the body too complex to be controlled.

"I suspect that the body's regulation of weight is so complex that if you intervene at this site, something else is going to happen to neutralize this intervention," said Lester Salans, an obesity researcher and emeritus professor at Mount Sinai School of Medicine, as quoted by the International Herald Tribune.