It's the curse of slimmers everywhere. And now scientists think they've discovered what actually causes yo-yo dieting - that is, when you go on a diet and lose weight, only to gain it all back (and more) soon afterwards. If you're a seasoned yo-yo dieter, you'll have probably lost and gained weight more times than you care to remember.
The hormones in question are called leptin and ghrelin, and the scientists discovered that people who have high levels of leptin and low levels of ghrelin are the ones who are the most likely to gain the weight back that they lost by dieting.
The researchers carried out tests involving 104 overweight people. Each was tested for level of hormones including leptin, ghrelin and insulin, and each just had lost weight through dieting. After eight weeks, the individuals who had already regained more than 10% of the weight they had previously lost were those who had the highest levels of leptin and the lowest levels of ghrelin in their blood. But there was no difference in terms of their insulin levels.
So how does this knowledge help people stay slim? Well the researchers are suggesting that nutritionists and other health professionals could identify people who are most at risk of gaining weight back after dieting by testing their hormone levels. Then once they know someone's weight is likely to yo-yo, they could design a diet that will help them keep the weight off.
Does your weight yo-yo? Have you discovered how to stop it piling back on?