Fat-Burning Hormone: Here’s Why You Need Leptin for Weight Loss

by Marixie Ann Obsioma, MT, undergrad MD

Published on August 4, 2021 and last updated for accuracy on October 10, 2021

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Fat-Burning Hormone: Here's Why You Need Leptin for Weight Loss

Several individuals who go on a diet and lose weight usually end up regaining the same pounds lost within a year (1).

There are several reasons why this occurs. For one, people view a “diet” as a short-term solution that does not really change behaviors. Another reason involves the fact that the body has appetite- and weight-regulating hormonal mechanisms that try to maintain homeostasis (or balance) over time. When we consistently take in less food for energy than the energy we expend through basal metabolism and activities like diet, our body responds to the imbalance by making us even hungrier (1).

Our bodies don’t generally want to change. If one tries to change the way that the body should function (i.e. causing an imbalance), our bodies usually respond with compensation mechanisms, such as boosting our appetite hormones (1).

A lot of people believe that weight gain and weight loss is all about calories and willpower. However, modern research on obesity disagrees. Scientists increasingly say that the hormone leptin is involved (2).

What is Leptin?

Leptin is a peptide hormone released by fat cells after gathering enough energy from calories in your diet. It travels to your brain, signaling the hypothalamus that you are full. As a result, your brain then shuts down hunger so you stop eating, which suppresses your appetite and burns fat stored in the adipose tissue (3) (4) (5). For this reason, leptin is also known as the “satiety hormone (5).”

The hormone interacts with areas in the brain that control hunger and eating behavior. Leptin levels tend to drop when one excessively decreases their calorie intake, exercises more, and loses body fat, thus the nickname “the starvation hormone.” The said factors are all involved in what is known as starvation mode (5).

Leptin also plays an important role in the regulation of the reproductive system, thyroid gland, adrenal glands, and growth hormone production (5).

Leptin does not affect food intake from one meal to another. Instead, it alters food intake and controls energy expenditure over the long term (4).

The hormone binds to and activates LEPR-B receptors in the brain. As leptin levels go up, your hunger should decrease, and you start to consciously and unconsciously increase energy expenditure. The feedback system helps most people to prevent too much weight gain (5).

Leptin has a more profound effect when we lose weight and hormone levels fall. It stimulates a huge appetite and increased food intake. The hormone helps us to maintain our normal weight, which unfortunately makes it difficult for dieters to lose those extra pounds (4).

The main regulator of leptin production is body fat or adipose tissue. Levels fluctuate depending on your current weight and body fat percentage. Given that the hormone is produced by fat cells or adipocytes, leptin levels usually increase when someone gains more body fat, and decreases when one loses weight (5).

In most healthy adults, changes in body weight trigger changes in leptin, which cause appetite to either increase when body fat falls or decreases when body fat rises. In some susceptible individuals, this energy-balance system seems to malfunction (5).

What Does Research Say About Leptin?

The hormone was discovered in 1994 by researchers who noticed one genetically altered group of mouse ate a lot and was obese. However, when the researchers administered a new substance leptin (from the word leptos, which translates “thin” in Greek), the mice lost weight (1).

After such, almost everyone interested in fat research was conducting their own research on leptin. During that time, the said research was a common “go-to” of obesity research, which could lead to leptin pills (1). However, this has not taken place (5).

Researchers initially thought that this discovery would be a blockbuster for weight loss, wherein if they could increase leptin in people who were overweight, it could be the much-needed cure for obesity (3).

However, like other things in biology, leptin is found to be more complicated than that. It turns out that leptin injections only worked on mice and people who were genetically leptin deficient, which is around 5 to 10 percent of the obese subjects (1).

Although research continues, there are still no successful weight loss therapies derived from leptin. An exception is found in rare genetic conditions where children who are born without leptin, which could cause childhood obesity. For these children, leptin treatment has shown promising results (3).

As of today, a major topic in the field of obesity research is the link between obesity and leptin. Some evidence suggests that obese-prone individuals do not respond to increasing leptin levels as non-obese-prone individuals do. For this reason, obesity is now associated with “leptin resistance (5).”

Researchers soon learned some facts about leptin that were not the same as what they initially assumed. One of these facts showed that people with obesity had plenty of leptin in their bodies but still gained weight. Also, they learned that leptin supplements don’t work, since they cannot get past the blood-brain barrier and are metabolized by the body (6).

Why Do You Need Leptin?

Besides regulating appetite, leptin has been found to play several roles in the body. This includes boosting the immune system, reducing inflammation, and creating healthy bones. Still, these roles require additional research to be fully supported (6).

Leptin works hand in hand with another hormone known as ghrelin, which signals hunger. Together, they are referred to as the hunger hormones, since they control how often and how much you want to eat. Still, scientists believe that leptin plays a more important role compared to ghrelin (6).

Although there are supplements of leptin found ineffective for weight control, doctors would also treat a few conditions with injections of a synthetic form of leptin. Among these are:

1. Congenital Leptin Deficiency

Congenital leptin deficiency causes uncontrolled hunger. It is usually observed early in life when children exhibit severe obesity and delayed puberty. Injections of a leptin analog are effective in controlling this condition (6).

2. Generalized Lipodystrophy

Generalized lipodystrophy is a serious condition wherein individuals have almost no body fat. Oftentimes, they accumulate fat in their organs, and develop metabolic health risks like diabetes. Since they have very few fat cells, people with this condition are not able to produce enough leptin. Patients are then treated with injections of synthetic leptin (6).

Foods With Leptin

A lot of food sources do not effectively make leptin available for your brain, so there is little point in searching for food sources with it. It is recommended to see your healthcare provider and discuss your condition, along with a possible satiety drug to add in your routine and steps to take in making lifestyle changes to increase your body’s leptin levels (6).

One of the ways to make leptin work properly inside your body is to get enough high-quality sleep. A study found that people who were sleep-deprived had high levels of ghrelin, which in turn makes you hungry. These individuals were also known to have lower levels of leptin, which makes you feel satisfied (6).

Moreover, your food choice is also important. As a matter of fact, researchers today are trying to look into the relationship between leptin and triglycerides – a type of fat that is also known as lipids. Research shows that high triglycerides seem to have an impact in the way leptin functions in the body. That’s why, a diet that is meant to lower triglycerides can help to boost leptin in your body (6).

To help you lower your triglyceride levels and help leptin work more effectively in your body, consider the following food with leptin (6):

1. Berries

Replace sugary treats with fruit in its natural form. Berries like blueberries, strawberries, and blackberries are lower in sugar compared to some other fruits. They can help you lower triglyceride levels.

2. Unsweetened Beverages

Another way you can lower your triglyceride levels and boost leptin in your body is to experiment with herbal, black, or green teas. It would also help to drink water with lemon or a fruit fusion to lower your triglycerides.

3. Healthy Oils

If you’re cooking, it’s best to use moderate amounts of canola oil, olive oil, or high-oleic sunflower oil for most uses. Flaxseed oil is also a good choice for non-cooking uses.

4. Vegetables

Eating raw, steamed, or roasted vegetables is a great way to lower your triglyceride levels. Choose kale or cauliflower instead of starchy vegetables like potatoes or corn.

5. Legumes

Peas, beans, and lentils are great sources of protein and fiber that can boost leptin’s functionality in the body. Try to avoid baked beans and foods with added sugars.

6. Lean Meat, Poultry, and Fish

When it comes to lowering triglycerides, fish is the best food choice. If you prefer other animal proteins, moderate your servings to about 3 ounces and prepare with healthy oil for added benefits.

7. Whole Grains

Instead of consuming white rice, go for brown rice. Also, whole-grain breads are much more effective than refined loaves. Consider switching to whole-grain pasta or a healthier version like those made from chickpeas to lower triglyceride levels.

8. Salad Greens

Don’t forget to eat your greens. Add more nutritious toppings, and consider salad dressings that are low in salt, sugars, and fats.

9. Mushrooms

Mushrooms are essentially high in nutrients yet low in calories, which helps them regulate your triglyceride levels and increase leptin levels in your body.

What is Leptin Resistance?

The National Institutes of Health clinically defines leptin resistance as “The failure of endogenous or exogenous leptin to promote anticipated salutary metabolic outcomes in states of overnutrition or obesity.” Simply put, it is when your “brain is starving, yet your body is obese (5).”

People who are obese have a lot of body fat in their fat cells. Since fat cells produce leptin in proportion to your size, people who are obese also have high levels of leptin (2).

Given how leptin is supposed to work to help individuals limit their food intake, a lot of obese people don’t have their leptin signals working to inform the brain that the body already has enough energy stored. This condition is known as leptin resistance (2).

How Does Leptin Resistance Work?

There are some possible explanations concerning how leptin resistance actually works. One theory is that leptin cannot get to the hypothalamus since proteins responsible for transporting leptin across the blood brain barrier are not working or are not present (1).

Leptin resistance is believed to be one of the main biological contributors to obesity. If your brain does not receive the leptin signal, it erroneously thinks that your body is starving, despite the sufficient energy present. As a result, your brain changes its behavior in order to regain body fat. More specifically, it encourages you to eat more to prevent starvation, and reduce energy expenditure in an attempt to conserve energy (2).

Since the brain is not sensitive enough to the hormone’s signals, an individual would require more food to feel full or satiated. Although there is no clear reason for this, experts believe that obesity alters several cellular processes that interfere with normal leptin signaling (5).

What Causes Leptin Resistance?

There are several possible mechanisms that lead to leptin resistance. Among these are (2):

Inflammation: Inflammatory signaling of your hypothalamus is likely a significant cause of leptin resistance in both humans and animals (2).
Free fatty acids: It is known that having elevated levels of free fatty acids in your bloodstream may increase fat metabolites in your brain and interfere with leptin signaling (2).
Having high leptin: Leptin resistance is initially caused by having increased levels of leptin (2).

All of these factors are elevated with obesity, which means that you can get trapped in a vicious cycle of gaining weight and becoming more leptin resistant over time (2).

Other causes of leptin resistance include consistently high insulin levels or an inflamed hypothalamus. Also, there may also be a genetic component to leptin resistance, which could be influenced by consuming processed foods that can trick your brain into craving more after when you should be full (7)

How Can I Treat Leptin Resistance?

Even if one is genetically susceptible to weight gain or obesity, there is still a lot they can do to help prevent this from happening – like eating a nutrient-dense diet, getting enough exercise, and taking steps to manage stress (5).

Research shows that the body has more powerful ways to defend itself against starvation by producing strong hunger responses than by defending against weight gain (5).

According to Dr. Michelle Sands – hormone, metabolism, and epigenetics expert, and author of Hormone Harmony over 35 – there is a lot that one can do to lessen leptin resistance. Some dietary and lifestyle remedies that you can apply for leptin resistance include (7):

Consuming healthy fats like avocado, coconut, olive oil, as well as fish and grass-fed, pasture-raised animals (7)
Removing added sugar from your diet (7)
Getting at least eight hours of sleep – Studies show that getting 8 to 10 hours of quality sleep per night results in better leptin sensitivity, reduced cravings, and a better balance of hunger and energy balancing hormones (7).
Having sufficient exercise – The National Institute of Health (NIH) reports that moderate aerobic exercises can improve leptin resistance in people with diabetes and obesity (7).

How to Make Leptin Work for You?

At this point, it’s important to keep in mind that leptin levels are not the only factor that controls your body weight. Other factors include: an overall diet, genetics, age, gender, activity level, gut health, and medical history (5).

However, research suggests that dietary choices, lifestyle changes, and habits can help you regulate leptin levels and help you maintain an overall healthy body weight (5). One of these factors involves the leptin diet.

The Leptin Diet: An Overview

The leptin diet was designed by Byron J. Richards, a businessman and board-certified clinical nutritionist. His company, Wellness Resources, manufactures herbal supplements that are designed to support the leptin diet. He is also the author of several books about leptin and its role in weight loss and health (8).

A lot of principles of the leptin diet are similar to those of other weight management programs. It recommends avoiding eating late at night, consuming additives like those found in soda, and eating too much carbohydrates (8).

The leptin diet also emphasizes the need for portion control. These recommendations represent sound nutritional advice. Furthermore, the diet is also accompanied by easy-to-maintain exercise guidelines that don’t require you to work out endlessly in order to lose weight (8).

Points to Ponder

Obesity is not usually caused by laziness and a lack of willpower. Instead, it may be due to leptin resistance, wherein people gain weight and have a difficult time losing it (2).

If you are concerned that you may be resistant to leptin, there are several steps you can take to live a healthier lifestyle (2). The best ways to avoid leptin resistance and a cycle of hunger and obesity is to lose weight, sleep regularly and consume a healthy diet (3).