Ghrelin vs Leptin: Two Warring Hormones

Today, we’re going to tell the story of two competing hunger hormones, ghrelin and leptin. If you’ve ever felt like you simply can’t control your appetite, or that something is wrong with you in your weight loss efforts, we hope this tale helps shed some light.

The truth about your insatiable appetite or the fact that you can’t “control” yourself? Your body is responding exactly as it’s supposed to. Your body has certain hormones that directly control appetite, designed to avoid both under- and overeating. When they work as intended in concert with one another, the result is a perfect balance. But with our stressful modern lifestyles, the standard American diet, and a lot less time for crucial self-care, these hormones can go a little haywire. They might even mistake your new, well-intentioned healthy habits as a diet akin to starvation instead. But not to worry! There are ways to get your hunger hormones back in balance and ensure they work as intended. 

First, a meet-and-greet with ghrelin and leptin.

Meet the Appetite Hormones

The truth is that there are at least 15 main hormones that have a role in appetite, from Cholecystokinin to Peptide YY. Even dopamine and serotonin play a role! But the two biggest, most well-known, appetite influencers are leptin and ghrelin.

Ghrelin

Ghrelin is the only appetite-stimulating hormone in humans, and is known as the “hunger hormone.” That means it’s responsible for making you hungry. It increases your desire for fatty and sweet foods, causes you to digest food more quickly, and decreases insulin secretion, among other things. When your stomach is empty, it releases ghrelin to signal the brain that it’s time to eat. Typically, ghrelin levels are highest before eating and lowest about an hour after eating. 

In those who are overweight, ghrelin levels are often lower than people that are a “normal” weight. (And look, we’re totally putting normal in quotations because we believe people can be healthy at any size. What does normal mean anyway?). If this is the case, ghrelin levels decrease only slightly after a meal, meaning the body doesn’t receive a very strong signal to stop eating. 

Leptin

On the flipside, leptin signals your body to decrease food intake and helps to regulate body weight. It’s considered the “satiety hormone” because it works to tell your brain that you have enough fat stores and aren’t starving. It has other functions in the body, but the main one is the long-term regulation of energy. It helps monitor how many calories you eat, how many calories you expend, and how much fat you store.

Leptin evolved to keep humans from going hungry or overeating, helping early humans survive. But as with many other hormones, leptin hasn’t quite caught up with our modern environment (and a surplus of available food). Leptin is produced by your body’s fat cells. The more fat your cells have, the more leptin they produce. High leptin tells your brain that there is plenty of body fat stored and you don’t need to eat, and low leptin signals the opposite. 

But sometimes, leptin signaling goes awry and you may develop leptin resistance. Despite the presence of ample body fat, leptin signaling may not work properly. Leptin may even be there, but the brain doesn’t see it. Without the proper leptin signal, your brain thinks it’s starving and changes its behavior, eating more and reducing energy output. This is why restrictive diets often fail or are incredibly hard to stick to. 

Influencing Leptin & Ghrelin Levels

We hope this context around leptin and ghrelin helps you see that even when you have the best intentions with your healthy habits, sometimes your hormones have other ideas. If you overeat or struggle in sticking to an eating plan you’ve been trying out, know that it’s often not a defect of willpower, but a hormonal imbalance instead.

Thankfully, there are ways to lower ghrelin and reduce leptin resistance. And many of them boil down to a healthy diet and lifestyle. I know, I know. You’re probably tired of us talking about something as unsexy as a healthy lifestyle. But it really is the key!

Balanced Diet

The typical diet advice of “eat less, move more”, while well-meaning, often results in your body entering starvation mode. Rather than drastically reducing calories, be mindful of the types of foods you’re regularly consuming and aim for a balanced plate. This includes eating enough healthy fat and protein to keep your body and brain more satiated. Almost all of the hormones that regulate appetite respond positively to higher protein intake. When you eat protein, it increases satiety and decreases hunger, in part by decreasing ghrelin. It’s beneficial for leptin resistance, too. 

In addition to eating more protein, eating enough fiber and decreasing your intake of processed foods is also associated with improved leptin resistance. Another unlikely cause of leptin levels that are out of whack? High triglycerides! While lipids might seem unrelated to hunger hormones, high triglycerides may prevent leptin from being transported to the brain. The best way to lower triglycerides? Decrease your carbohydrate and sugar intake. 

Regular Exercise 

So now that you’ve balanced your eating, it’s time to get moving. Moving your body on a regular basis may help improve leptin resistance, amongst a slew of other benefits. And the best part is, there’s something for everyone! Whether you enjoy hiking, swimming, weight training, or are interested in trying something else – exercise will positively impact your body and hormone levels! It will also help you build muscle and stabilize your weight, two other things that will help balance your hormones and regulate leptin and ghrelin levels.

Get Some Shut-Eye 

Are you tired of us bringing this up? Then get some sleep! Poor sleep increases ghrelin, and it’s also linked to hunger and weight gain. While resting should be the simplest recommendation on this list, we know that it can be easier said than done. (Un-)Fortunately, you’re not alone if you struggle with sleep, meaning that plenty of research has gone into helpful strategies to optimize the quality of your sleep. We like this article from Dr. Mark Hyman with some basic sleep hygiene tips.

At the end of the day, if you’re struggling to stick to the diet you’ve laid out for yourself, your unrelenting hunger isn’t your fault. The key is to ensure that you’re eating enough food, especially fat and protein, and focus on other pillars of health like sleep and movement. You’ll start feeling better and more energetic, and slowly your hormones will improve too. A win in our book.