Are Leptin and Ghrelin the Keys to Weight Loss?



Today we’ll settle the debate on whether Ghrelin and Leptin are the keys to losing weight and what to do about these critical hormones.

Losing weight is never easy, but with the right plan, diet and exercise program, it’s entirely possible. However, no matter what we do our hunger signals are controlled by

Why Do Most Diets Fail?

There are a few different reasons. The biggest reason is because often times, people see their diet as a short-term plan that will eventually come to an end. This means they don’t really change their lifestyle or even their behavior at all. It takes 30 days to build new habits and in that time it’s quite easy to break your new good habits. Successful dieting comes down to setting up guidelines and boundaries in your daily eating that you can stick with forever.

Success with long-term weight loss comes from permanent lifestyle change.

Easier said than done.

The second biggest reason why people fall back into their old ways, is that our body’s are trained to send out signals that get in the way of our fitness goals. We are often literally addicted to unhealthy foods and the cravings can be very strong. Unfortunately, we beat ourselves up over mistakes and often let one bad day of eating, totally derail us from our goals.

Everybody has both weight and appetite-controlling hormonal mechanisms that attempt to keep some level of consistency over long periods of time.

So when you decide to go on a diet and suddenly don’t eat as much food, you aren’t getting as much energy, so our bodies do exactly what we don’t want them to do and give off the signal that it’s hungry.

Basically, your body resents change. It’s honestly amazing how much our bodies adapt to our habits, with eating and otherwise. Our bodies also will resent the change sometimes, even when it’s a healthy transition. So when we try and mix things up a bit and change our diet, the body’s natural response is to cope by certain compensating mechanisms, like giving our appetite a big boost through hormonal signals.

So you might be wondering how in the heck you can lose weight with your body working against you. And we don’t blame you – that’s why so many people struggle with it. That’s also why we’re here to help.

There two essential hormones that have a major hand in our appetite and hunger signals.

What are they? Ghrelin and leptin. WebMD classifies these as your “Hunger Hormones.”

Let’s dive headfirst into these two hormones to see what they can mean for you.

Leptin weight loss 2

Ghrelin and Leptin Breakdown

Leptin and ghrelin are two of the main drivers in keeping your appetite in check. So, obviously, so if you’re trying to cut fat, it’s time to get acquainted with these hormones.

Basic equation: when you’re hungry, you eat. When you feel yourself getting hungrier, you eat more and with less control over what you grab for. When you start eating more, your body will do one of two things: gain weight or build muscle.

Ghrelin and leptin are considered minor signals with some pretty huge effects. Basically, this duo is secreted in various parts of your body but they primarily impact our brain.

Leptin is secreted mostly within the fall cells, but it’s also found in the heart, stomach, skeletal muscle and placenta. Leptin is a good thing, because it acts as the factor that can decrease that extreme hungry feeling. So the question is, how do we activate this hormone to gain the benefit of suppressing hunger.

Ghrelin, on the other hand, is like Leptin’s evil cousin. Found mostly within the stomach’s lining, Ghrelin gives your hunger a huge boost. This is the primary signal that makes you hungry and leads to reckless eating and hunger-crazed decisions, like picking up a cheeseburger instead of a chicken breast. Taste cravings are a dangerous thing when mixed with the chemical signal that we “need to eat or we’ll die.”

Something these hormones have in common?

Both ghrelin and leptin respond to how much you’ve eaten that day.

Leptin generally interacts with fat mass, so basically, the more fat your body has, the higher amount of leptin your body will produce.

Then both of these hormones wake up your hypothalamus. Even though it’s a long medical term, it’s the section of your smarty brain that’s about the same size as an almond! So pretty much its name is bigger than its actual size.

What does all this mean for your weight loss? Well, hormones and the signals they give off get seriously screwy when obesity comes into the equation.

Quick History Lesson

Way back in 1994, a group of researchers realized that a specific genetically altered mouse was kind of a pig. He ate a ton and was obviously obese.

So these researchers decided to do what they do best—research and experiment. They decided to try supplementing with something new called leptin. Leptin comes from the Greek word “leptos,” which means thin.

You can probably guess what happened next: the mice started to lose weight.

It goes without saying that this was a huge discovery. In fact, shortly after this, virtually everyone was interested in experimenting with the connection between weight loss and leptin.

Now remember, we’re talking about 1997 here. Not everyone made the best choices back then. Fashion was pretty awful, healthcare was kind of iffy. Anyway, this was a really big deal. So scientists were thinking, now all we have to do is produce mass amounts of leptin pills. Then, everyone would lose weight, right?

Right? Wrong. Like a lot of things, there wasn’t enough evidence to start this process just yet. Leptin is a heck of a lot more complicated than anyone originally thought.

After getting off of their 1997 leptin high, researchers took a deeper look at their findings. They discovered that injections of leptin were only successful on mice and people who considered genetically deficient in leptin.

What amount of mice and people are considered part of this? Around 5-10%. Not really an impressive number. So that mean’s the leftover 90-95% of the population would have been basically out of luck. So it was back to the drawing board.

How Does Leptin Naturally Work?

Leptin is created like this: Adipose tissue (also lovingly known as fat) creates leptin, which is then secreted into your body’s circulatory system. From there, it travels all the way to the brain’s hypothalamus (that almond-sized part of your brain).

Leptin then gets a little bossy. It lets the hypothalamus know the brain has enough fat so we either need to stop shoveling in the food, immediately.

While there’s still some research to be done, it is believed that leptin plays a role in increasing metabolism. We’ll revisit this.

The basic rule of thumb is this – the higher levels of fat your body has, the more leptin you’re going to be producing. On the other hand, when you drop how much food you’re consuming, your body’s metabolic rate increases. But, frustratingly on the flip side, when you ingest less fat, your body isn’t going to create as much leptin, so you’ll keep getting hungrier.

Kind of frustrating, huh?

When it comes to losing weight, the more leptin hormone you have in your body, the better results you’ll see. So the question is how to create that state in the body.

Ghrelin Weight loss

Leptin Resistance

Here’s another issue, your body can actually start to resist leptin. When you’re eating more fat, your body should be experiencing an increase in leptin levels. This should then trigger the brain to stop eating, or eat less on the whole. This is not the case for some.

If your body is leptin resistant, you may not feel sated even after overeating because the leptin signal to stop eating is not hitting the brain. Essentially this causes the brain to tell you to keep the grub train rolling. This is a difficult cycle to break and if you feel that you might fall into this category, you should consult your doctor!

There are actually a few similarities between insulin resistance and leptin resistance. Insulin resistance happens when – you guessed it – there’s a ton of insulin that’s being created but the brain and your body have decided to ignore its signals. These kinds of resistance tend to be more common among those who are unhealthily overweight.

Here’s an interesting fact to go along with that: it appears that fructose may encourage your leptin resistance.

We’re still learning more about leptin resistance but one idea is this: Leptin can’t get to the hypothalamus. Why? Because the proteins that generally take it all the way across the blood brain barrier either aren’t there or they aren’t working properly. This could be because there’s a major build up of leptin. We’ll be keeping an eye on this topic ongoing.

Now let’s talk about ghrelin for a minute.

The Deal with Ghrelin

After leptin was discovered, 7 years later came ghrelin to much less excitement. Basically ghrelin has one signal, all the time: HUNGRY.

Your stomach produces ghrelin when it doesn’t have any food in it. And, much like the leptin, gives your brain an appetite signal. Ghrelin is pretty high right before you start eating something. Then, after you finish, the numbers drop off.

And when you’re looking to drop some pounds, you want to have less ghrelin.

Both of these hormones are survival mechanisms that help manage your hunger and appetite. So when you’re trying to get rid of a few pounds, your body changes its response by altering the hormone levels – and then, you end up feeling hungrier.

Here’s what one research group did – they put 160 obese/overweight women and men on a calorie cut back diet for a total of 2 months.

The diet was about 500-600 calories less a day than usual, with about 15% of the calories mixed in from protein, another 30% from fat and the rest of carbs. And there wasn’t any type of change in their levels of exercise and physical activity—only their food intake.

Then the researchers checked things like body weight, waist, and body fat. They also decided to grab some blood samples right after 8 weeks and then again six months later.

Their results? The men lost about 5.9% of their body weight, while the women lost about 4.5%.

Okay, seemingly decent results. The really interesting part, however, are the blood samples that were taken.

The participants who lose more than 5% saw a huge decrease in both leptin and insulin compared to those who didn’t get above 5%. This group also had higher levels of ghrelin.

Basically, somehow weight loss is connected to drops in insulin and leptin. Now when researchers checked things out six months later, the group that lost more than 5% had continued to lose weight. The other group simply regained the weight they had worked so hard to lose.

Now back to our original point – the dieters that went up regaining that weight. This study proves that hormonal mechanisms are different for men and for women.

There’s one huge take away – you will probably never find the magical solution to starving off hunger and wiping away body fat. The study shows that there isn’t one single hormone that controls it all – your hunger, your composition, your appetite. Likewise, your own personal hormone profile may be different in its own way. So you can’t predict how it’ll affect you.

Improving Leptin and Ghrelin Levels

When you’re looking at improving your ghrelin and leptin levels, since supplementing isn’t really an option, studies show that getting regular sleep and taking fish oil can be your best bet. Stress has major impact on your body’s hunger signals. It’s important to take time for yourself or you might just find yourself eating your feelings. And of course, like most weight loss journeys, you want to get as much physical activity as you can, as well as set goals for yourself and track your progress. Remember that at the end of the day calorie deficit will dictate weight loss.


So, there isn’t one sole solution that’ll give you a quick fix when it comes to managing your hunger hormones. Instead, this will come with some serious hard work and dedication. These hacks will improve your process.

  1. Take Fish Oil

There’s a ton of research that shows Omega 3 fatty acids can aid in decreasing hunger. Not to mention fish oil totes a huge list of other benefits from brain function to anti-inflammatory properties. Side note: this is one that the Gym Junkies staff takes daily!

  1. Get More Sleep

Lack of sleep can lead to more ghrelin production and less leptin. Cortisol, or stress hormone also triggers us to eat impulsively and satisfy cravings. This is not going to help you lose weight, so get your sleep.

  1. Manage Stress

It’s easy to get frustrated on your weight loss journey. We all have setbacks but remember that your attitude towards these setbacks can not only impact tomorrow, but have a huge effect on your stress level which can throw off your appetite signals.

Try these fixes and remember that while you can’t take a magic pill to fix your appetite signals. Focus on long term weight loss by eating nutritious meals and creating a calorie deficit along with lots of physical activity.

-Terry Asher

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Gym Junkies Founder & Editor in Chief at Gym Junkies LLC
I’m Terry and I’m here to help you achieve your fitness goals. I truly believe anyone can achieve the figure they want with the proper guidance. Through my extensive fitness blog, top fitness videos, leading workout supplements, and top selling eBooks, I have been able to help thousands of people online lose weight, tone up and get in shape. My passion is helping people all around the world change their lives for the better.
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Are Leptin and Ghrelin the Keys to Weight Loss?
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Are Leptin and Ghrelin the Keys to Weight Loss?
Today's article sheds light on Leptin and Ghrelin, two key components in regulating your appetite. We'll find out if these are the key to weight loss.
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Gym Junkies
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