Why do most people who go on a diet and successfully lose weight end up putting it back on within a year?

This is an interesting question and the full answer is too complex to cover in this short post, but one of the biggest contributory factors to this problem and the one most relevant to this article is the role played by the hormones Leptin and Ghrelin.

A quick biology lesson:

Homeostasis is the process by which the body attempts to keep everything in balance, basically, the body tries hard to keep everything the same. In most cases, this is a good survival mechanism. But unfortunately, it also means that when we try to change our weight or body composition our bodies fight us every inch of the way.  Hormonal mechanisms that try to maintain homeostasis kick in and starts messing with our heads by making us feel more hungry.

Ghrelin and Leptin

As mentioned earlier two important hormones that are responsible for shaping our appetite and hunger signals are leptin and ghrelin.

Leptin and Ghrelin play opposite roles in controlling appetite.  Leptin which is secreted primarily in fat cells, as well as the stomach, heart, placenta and skeletal muscle, decreases hunger, while Ghrelin which is secreted primarily in the lining of the stomach increases hunger.

Both hormones respond to how well-fed you are, the more fat you have, the more leptin your body produces, and the more fat you lose the more Ghrelin your body produces. So the more fat you lose the more your body tries to trick you into eating more to maintain the weight at which it has become accustomed.

Leptin resistance

So technically the more fat you have the less of an appetite you should have and your body should stop you from eating in an attempt to lose the excess weight. But this generally doesn’t happen as we can become leptin resistant as too much fat can disrupt the signaling mechanism, making you unable to detect the leptin and making your body think it is in starvation mode and instead revving up your appetite in an attempt to make you eat more. A vicious circle that leads to obesity.

Controlling Ghrelin

so the ideal situation would be one in which we could control the production of these two hormones so that we can reduce our fat and Calorie input whilst at the same time reducing appetite.