The Hormones That Control Cravings

by Dr. David Minkoff November 07, 2022 6 min read

An athletic man resting on steps checking his smart phone.

There are several things that control cravings or make it hard to get off sugar, as covered in this article here: What Causes Cravings For Sugar & Junk Food?

Causes mentioned in that article include hormones, messenger chemicals in the body that tell the cells what to do or not do, how to use energy or not, whether to build muscle or break it down, or add fat or burn it. 

Now, while Insulin, Cortisol, and several other hormones play a part in all of this, there are two specific hormones that control hunger and, in large part, your cravings: Leptin and Ghrelin.

Leptin is a hormone that sends messages to stop or lower cravings, and Ghrelin sends messages to increase them. Of the two, Leptin seems to be the one most in control. 

Now, this is an area where much more research needs to be done, but we do know key facts about these hormones and how they operate. 

First, when we eat there is always some fat created and broken down, even if minimal. This is a constant process. 

There are also free-floating fatty acids in the bloodstream which can be used for energy if needed. 

And, the more fat you have on your body, the more free-floating fatty acids you will have in your blood vessels.

Leptin is a hormone produced by the fat cells. It’s produced every time we eat, but also when there are higher amounts of fatty acids in the bloodstream or stored in our fat cells. 

The Leptin that’s produced then goes to the brain where it hits specific leptin “receptors” and passes on the information that “we’ve had enough food and don’t need to eat anymore,” and that we can dip into our fat stores for energy now. 

In short, it tells us to not feel hungry and that it’s okay to burn fat as well.

But, it’s key that fat levels have been increased, because we’ve eaten and that signals the production of Leptin so it goes to the brain to say we don’t need more.

Then, if time passes and leptin levels in the bloodstream lower, the brain sees this and knows it needs more food. It then directs Ghrelin, the other hormone, which is released by the stomach to increase hunger cravings, to not dip into fat stores for energy. 

This is why Ghrelin levels are highest before a meal. Ever had your stomach growling because you’re hungry? That’s Ghrelin.

But here’s the problem: the more fat the individual has, the more free fatty acids there are in the bloodstream and the more Leptin the fat cells release.

These should then be seen by the brain telling it that you don’t need any more food right now.

So, the more body fat you have, the less hungry you should be and the more willing your body should be to burn fat, right?

So what’s happening here? 

Well, like insulin resistance, there is something called Leptin resistance, where the brain literally doesn’t “see” the Leptin. 

And, as Leptin is the brain’s indicator that the body has eaten and has enough energy stores – if it doesn’t see leptin – then it thinks it still needs food and so directs the release of Ghrelin to make you hungry to eat more.

Despite having just eaten, we can continue to have more cravings. Your brain doesn’t see any leptin, thinks you’re starving and works very hard to make you eat more — even when you’ve eaten plenty and have excess body fat. It will direct your body to not burn fat, even when you exercise and work hard to get rid of it. 

These cravings can be very strong. After all, your brain thinks you’re starving.

What Causes Leptin Resistance?

One of the main things that causes Leptin resistance, your brain not seeing the Leptin and so thinking you’re still in need of food, is excess triglycerides in your bloodstream (triglycerides are the most common type of fatty acid in your blood, there are many types). 

You see, there is something called the blood-brain barrier. This is a literal barrier that allows certain things through to the brain while keeping out other things, all to protect the brain. Leptin must pass through this barrier to be seen by the brain.

Excess triglycerides can get stuck here and start clogging this barrier. This makes it harder for nutrients and other chemicals and hormones to get through — including Leptin. 

Say you’ve just eaten and plenty of leptin is in the blood. It can’t make it through the barrier to be “seen” by the brain, so the brain thinks you’re still hungry, despite having just eaten a lot of food, and instructs the stomach to release more Ghrelin, making you hungry again.

That’s one thing we need to address — too many triglycerides clogging the blot-brain barrier so Leptin can’t pass through.

Another point is having overly high levels of Leptin seems to increase leptin resistance. The Leptin receptors in your brain become desensitized to the Leptin because it's always there, since you eat so much, there is a surplus. 

Then we have inflammation and Cortisol. High levels of inflammation raise Cortisol, which also raises Ghrelin levels, increasing your appetite. So if you have inflammation causing higher cortisol release, or just higher levels of cortisol due to diet or poor digestion, we get increased Ghrelin.

And lastly, there is one more fat type that causes trouble here which we will address in another article — Trans Fats.

The fat that raises inflammation the most is trans fat, a molecularly altered fat that the body does not recognize and cannot use well and which only causes trouble.

Trans Fats both raise inflammation and they also clog the blood-brain barrier and can cause even more trouble than triglycerides there.

So we have a few things to handle here, but this Leptin—Ghrelin situation is one of the largest factors in yo-yo dieting, losing weight and then gaining it all right back again.

You work hard to reduce processed sugar and calories and somehow push through the withdrawals and lose fat. Maybe your cells become insulin-sensitive again and come off their addiction to sugar. Your small intestinal bacteria numbers go down as they’re dying off due to less of the food they thrive on (processed sugars). 

The blood-brain barrier is still clogged and so the brain still isn’t “seeing” the Leptin and so still sends Ghrelin to keep you hungry. 

Then we give in and go back to our old ways, gaining all of our fatback and then some.

So how do we fix this?

Reversing Leptin Resistance And Lowering Cravings

First, we need to get rid of these processed sugars as these are the main things that create so much excess triglycerides in the bloodstream which then clog the blood-brain barrier and prevent leptin signaling in the first place.

Next, avoid processed foods. These, even when made from organic ingredients, are often in a form after processing that our digestive system has trouble breaking down and which can lead to inflammation, especially from rancid refined fats and trans fats. 

Also, partially digested proteins contribute to inflammation as we saw in this article, so we need to make sure the gut is in good health and properly functioning.

And, of course, get good sleep. Poor sleep, along with inflammation, raises cortisol levels which releases Ghrelin, making one more hungry just because they’re tired.

Most importantly, protein is actually the key thing that reverses Leptin resistance, which makes sense. 

The enzymes that break down triglycerides and trans fats, including those clogging the blood-brain barrier are all made of amino acids. 

But these enzymes have a relatively short life and new ones constantly need to be made. The less amino acids one has, the less enzymes their body can produce overall, lowering the breakdown of fat among other things. 

This is one reason many people start having lowered appetites and less cravings for sugary junk foods after taking PerfectAmino

Their bodies are now getting what they need to produce these enzymes in enough volume to start reversing Leptin resistance. 

Find out more in our Guide to Fat Loss & Lean Bulking.