University of California researchers have come out with findings that dispel the halo around dieting regimes. Not only do would-be weight losers gain back those pounds , they also stand higher risks of developing diabetes, heart attacks and strokes.
The researchers who published their finding in the journal American Psychologist, based their research on thousands of dieters who underwent dieting plans. The research covered also more than 30 studies on the subject.
Says lead researcher Dr Traci Mann: "You can initially lose 5 to 10 per cent of your weight on any number of diets.
"But after this honeymoon period, the weight comes back. We found that the majority of people regained all the weight, plus more.
Sustained weight loss was found only in a small minority of participants, while complete weight regain was found in the majority."
Contemporary research has shown the repeated rapid weight gain and loss associated with dieting can double the risk of death from heart disease, including heart attacks, and the risk of premature death in general.
Such yo-yo weight loss has also been linked to stroke and diabetes and shown to suppress the immune system, making the body more vulnerable to infection.
Yet, in addition to the cardiac impact, there are also concerns about how yo-yo diets affect one's ability to burn calories at all.
According to Carole Myles a personal trainer from Edinburgh, regardless of size, those who take in too few calories damage their exercise capability.
"Whenever you rapidly reduce your food intake, you slow your metabolism," says Myles. "Your body goes into starvation mode and so stores any calories you do consume. At the same time, your muscle mass is reduced and so you lose the ability to burn as many calories. The problem is that once you start eating normally again - which, inevitably, you do - your metabolism may not recover and so you gain weight more quickly than you did before", she adds.
Says Mann: "We decided to dig up and analyze every study that followed people on diets for two to five years. We concluded most of them would have been better off not going on the diet at all.
"Their weight would have been pretty much the same, and their bodies would not suffer the wear and tear from losing weight and gaining it all back.
"The benefits of dieting are simply too small and the potential harms of dieting are too large for it to be recommended as a safe and effective treatment for obesity."
Mann who advises would-be slimmers to swap calorie-controlled diets for a balanced diet coupled with regular exercise, adds: "Exercise may well be the key factor leading to sustained weight loss.