Experts believe the dieting ups and downs when women have trouble keeping off the weight that they have worked so hard to lose may be due to a certain type of protein in their blood.
They found the protein angiotensin-converting enzyme that regulates blood pressure was distinctly linked to weight gain post-diet in women.
This discovery may pave the way for a test that will identify dieters who are vulnerable and unable to maintain their svelte physiques after weight loss.
Lead researchers, Edwin Mariman, professor of functional genetics at the University of Maastricht in Holland stated, "It was a surprising discovery, because until now there has been no clear link between this protein and obesity.
"We do not yet have an explanation for the results, but it does appear that it should be possible within a few years to use this finding to develop a test to show who is at high risk of putting weight back on after a diet."
In order to determine why some women gain weight post diet, researchers from eight European countries, including the UK, analyzed the blood of around 100 females aged from 20-45 years.
Half of the study subjects were able to successfully keep off their weight or lose more of it post-diet weight while the remaining regained the weight.
The analysis revealed that 80 percent of the dieters who piled on the pounds after dieting had heightened levels of angiotensin-converting enzyme.
Though the mechanism behind the protein affecting the dieters is ambiguous, researchers theorize it may be interfering with the hormones that regulate how full we feel by making the body store extra fat and water.
Dangers of yo-yo dieting
According to experts, "yo-yo dieting" carries psychological and physiological health hazards.
Repeated cycle of loss and gain in weight with dieting elevates the risk of death from heart disease, including heart attacks, and increases the odds of premature death in general.
In addition, a history of ups and downs in weight weakens the immune system making the body more vulnerable to infection. The yo-yo pattern has also been linked to stroke and diabetes.
The strain can take a psychological toll. Many dieters perceive each unsuccessful attempt to keep weight off as a personal failure. This leads to erosion of self-esteem, depression, and even guilt.
Dr Susan Jebb, of the Medical Research Council’s nutrition centre in Cambridge, an expert on the research team stated, “Despite what we might think, people are not bad at losing weight – where they really struggle is in keeping it off.
"And the reality is that most research is focused on getting that initial weight loss, rather than the strategies that people need to keep the weight off in the long-term.
"Yo-yo dieting is psychologically upsetting for people and repeated cycles which feel like failure breed a lack of self-confidence."
The latest study was published in the journal 'PLoS One.'