Leptin vs Ghrelin

Armed with a basic understanding of the macronutrients - fat, protein and CARBS (a.k.a. sugar) - it’s time to discuss hormones. First of all, what is a hormone? For now, let’s think of it in its simplest form: it is a chemical that is released by one part of the body to deliver a memo to a different part. How does the hormone know where to deliver the message? Most biology books suggest that the hormone is like a key, and it only opens one lock. In other words, the intended recipient has a shape/lock that only the intended hormone/key fits into.

If you are guilty of overeating and are overweight or obese, it might not be your fault at all. The guilty party might be a little-known hormone called leptin. After we have eaten a meal, our body is supposed to release this little fella and send him off to our brain to tell us that we’re full – to basically tell us to stop eating. Leptin is actually dispatched from our fat stores with a clear message to say we’re stuffed, stop sending us more supplies, we’re overcrowded.

If something goes wrong with our leptin and it doesn’t want to get out of bed and go to work, then we will crave food all day and pile on weight. Not only that, when leptin is having a lie-in, his colleagues in the metabolic department slow down too. It’s a double blow for our body. We feel hungry, we consume more food, and our slowed metabolism isn’t going to use much of it for fuel.

As Dr Michael VanDerschelden explains in The Scientific Approach to Intermittent Fasting, “When we eat a meal under normal conditions, leptin rises, blocks hunger and causes the thyroid to release thyroid hormones to increase metabolism”.

When we eat too many CARBS, there is a heightened possibility of developing type 2 diabetes. This is where fat cells can become insulin resistant due to a constant bombardment over a prolonged period of time. Sadly, for those who are overweight or obese, it’s the same story with leptin. Over time as you get heavier and heavier, your body cries out for help and dispatches more and more leptin to the brain in an attempt to rein in appetite and stop us from eating. With so much leptin knocking on the door, the brain refuses to listen. It then doesn’t realise that it has been fed and thinks it’s starving. Not only do you carry on eating, but also the brain warns the thyroid that you are in a period of starvation and tells it to slow down your metabolism. Doubly unhelpful whammy! So now with your slow metabolism, feeling tired and constantly hungry, you sit on the sofa and scoff more foods high in sugar, because they’re what’s going to make you feel fuller faster. It’s a race to the bottom in more ways than one!

If you are overweight, there is every chance that your body has become resistant
to leptin. So how do you get the brain to start acknowledging it again? Simply by following these four important primal beliefs: eat healthy fats and not CARBS; intermittently fast; get more active; and consume plenty of fibre - as it is believed to help repair leptin resistance.

kicking carbs

Throughout your studies at Health Results, you are going to discover how vital it is to develop the right type of bacteria in your gut. One way to nurture leptin is to develop colonies of bacteria that support it and remove those that can damage its production. Put another way, some varieties of bacteria can sabotage leptin production, causing us to overeat.

Ghrelin is the opposite of leptin. This hormone is the one that informs us that we are hungry. Ghrelin is essentially our hunger hormone. Before we eat, he runs around screaming to be fed. But after we have eaten, he is sent to the bedroom to awaken leptin and tell him to go to work.

Most people go and eat as soon as they hear ghrelin and his stomach rumblings demanding to be fed, but if we can resist these demands, wonderful things start to happen inside our body. First of all, we kick-start our automated repair process, we begin to fight inflammation (which is one of the biggest factors of modern disease) and we stimulate human growth hormones (HGH). What’s best is Mr Ghrelin gets a little angry when we don’t listen to him, so recruits more and more of his ghrelin family to assist him in trying to get us to eat and the more ghrelin there is in our body the more good it does. Combine this with exercise and we will increase our HGH even more.

As you will read later, there are great gains for most people in skipping breakfast. One of the scientific reasons for this is that there is a lot of ghrelin in our bodies after a good night’s sleep and if we can resist its calls for food and exercise in this fasted state, then our health is really going to reap the benefits.

Professor Tim Noakes

Professor Tim Noakes

Carbs do not satisfy hunger – they stimulate it. Most of the food in question is processed and developed with one purpose in mind: to make you want more. They are tested and refined to the point where they are as addictive as they are destructive. Scientists even have a name for this: they call it the ‘bliss point’. Addictive foods produce continual hunger, and so are the key drivers of the obesity/diabetes epidemic.


I was talking to a lady who had lost 60kg, and she told me that when she was fat, she woke up in the morning hungry and the only thing that drove her all day was hunger and that it was always there, it was incessant. Sadly, if you ask fat people that, that’s what they will tell you. They say the key driver is hunger. And the tragedy is that you can reverse it so quickly by cutting the carbs and controlling the sugar addiction.


Dr Dan Maggs

Dr Dan Maggs

A low carb diet in part works by removing hunger. Once you reduce your carb intake, you no longer feel hungry, even when you are fasting.