Two hormones are the key to yo-yo dieting

Two hormones – leptin and ghrelin – may well be the key to weight loss that lasts, say researchers.  The levels of these two hormones in your body could also explain yo-yo dieting, where dieters put the weight right back on.
Most diets concentrate on calorie counting, but it is the impact that diets have on the levels of leptin – which tell you when you are full - and ghrelin – which tell you when you are hungry - that will determine if the weight stays off.
The hormones work differently in men and women, researchers from the University Hospital Complex of Santiago have discovered.  Ghrelin levels have a bigger impact on weight gain and loss in men, and leptin in women.
The researchers studied the blood levels of ghrelin, leptin and insulin on 104 overweight people who were put on a low-calorie diet.  Insulin levels didn’t have any bearing on weight, but those who gained 10 per cent of their weight after eight weeks had higher levels of leptin.  Although leptin is the hormone that tells us when we are full, their findings suggest that the hormone was not functioning properly.
(Source: Journal of Clinical Endocrinology & Metabolism, 2010; 95: 5037).