What is Leptin?

Many people believe that weight gain and loss is all about calories and willpower. However, modern obesity research disagrees and scientists increasingly say that a hormone called leptin is involved.  

Leptin is a master hormone in the body that controls hunger and feelings of satiety. 

Leptin is a hormone produced by the fat cells in your body. Its main role is to regulate fat storage and how many calories you eat and burn. It is often referred to as the “satiety hormone” or the “starvation hormone. The name leptin comes from the Greek work “leptos” which translates as “thin. Leptin is supposed to tell your brain, the hypothalamus, that when you have enough fat stored, you don’t need to eat and can burn calories at a normal rate.

Leptin is the way your fat cells tell your brain that your energy thermostat is set right meaning the more fat you have, the higher your baseline levels of leptin will be

The brain constantly monitors leptin levels and when your leptin is working properly, you’re in energy balance or homeostasis, burning energy at a normal rate and feeling good.

Leptin (2)

But what if your leptin is not working properly?

When the hypothalamus, can’t see the leptin signal the brain interprets this as a state of starvation and will direct the body to do what it must to increase energy stores. The hypothalamus relays messages to the sympathetic nervous system to conserve energy and reduce activity.

Furthermore, the hypothalamus wants the body to increase its energy storage and will therefore continue to facilitate insulin release from the pancreas in order to promote the storage of energy into fat cells and thus weight gain happens. The hormone insulin, which maintains blood sugar levels in the blood, blocks the leptin signal in the brain. The more insulin in the blood, the more energy is stored into fat cells instead of being used for energy.  Thus, defective leptin signalling in the hypothalamus is what brain starvation is all about despite obesity.

The mechanisms of defective leptin signalling occur in two ways: leptin deficiency and leptin resistance:

  • Lepton deficiency: Leptin cannot be produced and our brain is in a constant starvation mode. In this case This is a rare condition when people born without the ability to produce leptin and they are constantly hungry and quickly become obese. When people with the condition were given leptin injections, they lost weight.
  • Leptin resistance: Leptin is secreted but the hypothalamus can’t see the leptin and therefore the brain thinks that we are starving. Both insulin and leptin resistance are caused when the body is subjected to excess amounts of insulin and leptin due to a highly refined diet with an excess of sugar and refined carbohydrates, as well as excess fat storage in the body.

The more refined non-nutrient foods, the more insulin, the more fat stored, the more leptin

People who are obese have a lot of body fat in their fat cells thus also have very high levels of leptin however, their leptin signaling isn’t working. Their brain thinks that they must eat in order to prevent starvation and it also decreases their energy levels and makes them burn fewer calories at rest.

Leptin resistance is now believed to be one of the main biological contributors to obesity.

Leptin resistance is sensed as starvation, so multiple mechanisms are activated to increase fat stores, rather than burn excess fat stores. Leptin resistance also stimulates the formation of reverse T3 (a thyroid hormone), which blocks the effects of the thyroid hormone on metabolism.

When researchers tried giving leptin to ordinary overweight or obese people as a weight-loss treatment, the experiments were unsuccessful.  It turned out, Leptin didn’t have that effect in obese or nonobese individuals. That’s a strong clue that leptin is just one piece in a much larger puzzle that includes genetics, environment, and lifestyle. Also, it makes no sense to give people leptin if they have an impaired response.

High and poorly controlled leptin levels as a result of being overweight are very pro-inflammatory and play a key role in other pro-inflammatory biochemical manufacture, which leads to inflammatory disease such as heart disease, arthritis and diabetes. Leptin is probably much more important to your heart health than cholesterol, yet very few general practitioners know anything about it. Leptin is very important in keeping the immune system happy and chronic inflammation occurs in the face of inadequate leptin signaling, and that’s part of cardiovascular disease.

So, why Leptin is important for weight control?

As one of the master hormones, leptin influences the production and secretion of other hormones that regulate metabolism, such as thyroid hormones T3 and T4. When leptin levels are high, your production of T3 and T4 will also be relatively high, allowing you to burn fat faster; when leptin levels drop, these other hormones go too.

Have you ever wondered why it’s easier to drop weight when you have more excess weight to lose? One of the important reasons is the fact that leptin is produced in the fat cells. However, leptin levels also share a direct relationship with caloric intake—when you eat fewer calories, your leptin levels drop considerably. Leptin is often called the anti-starvation hormone. Your body is slowing your metabolism to keep you alive when food is scarce. This, in turn, lowers your other fat-burning hormones, bringing your fat loss to a crawl!

Fat-loss catch-22
Leptin is decreasing your hunger for survival but this also compromises your fat loss efforts.

You need to eat less to burn fat, but eating less compromises your body’s ability to produce leptin. And the less leptin you produce, the hungrier you become and the more likely you are to eat more than you need. As your body starves or loses weight, leptin release reduces and appetite should return due to ghrelin, the hunger hormon, release from the stomach. 

The Leptin Cycle (2)

Not only is leptin part of the hunger system, it’s also part of the reward system. When your leptin levels are low, food is even more rewarding. When your leptin levels are high, that’s supposed to extinguish the reward system so that you don’t need to eat so much, and food doesn’t look nearly as good.

Many dieters struggle with weight loss because of their feelings of hunger.  They try to lose weight trying unsafe fad diets but their appetite gets in the way.

So, what is the solution?

The answer is convincingly diet…food choices and getting rid of excess fat stores, as well as lifestyle; movement, sunlight and sleep are important

Not only the size and frequency of meals have an effect on circulating leptin levels, but also the composition of a meal is a determinant of leptin levels.

How to increase leptin levels to control hunger?

  • Moderate exercise for 30 minutes 5 days per week.  This helps with both weight loss and hunger but the research is mixed on leptin levels. 
  • Get 7-8 hours of sleep each night.
  • Adequate protein intake (1 mg per Kg body weight)14.  Higher protein diets decrease appetite also to decrease leptin resistance. 
  • Add fish oil supplementation
  • Avoid high fructose corn syrup and sugar
  • Manage your stress.  It helps with cortisol levels and hunger. 

How to restore leptin sensitivity?

  • Ensure enough sleep. Sleep regulates your leptin and ghrelin levels. Not enough rest and your body starts producing too much ghrelin. Make sure to get about 8 hours every night.
  • Say no to sugar and simple carbs. Simple carbs (refined, sugary, and generally white) spike your insulin levels. Eat complex carbs in moderation like darker, unprocessed grains, such as whole oats, quinoa, and some whole wheat pastas tend to have more nutrients.
  • Cut out highly processed food pre-packaged food and high fructose corn syrup. Fructose that occurs naturally in fruit, is not enough to affect your leptin sensitivity.
  • Avoid snacking too much. When you are constantly eating, even small amounts, during the day it keeps your liver working and doesn’t give hormones a break.
  • Avoid severe calorie restriction. Like cutting out carbs pretty much entirely. If you’re not getting enough nutrients, your body will start shutting down and your hormones will be thrown out of whack causing you to be so hungry.  Evidence suggests that women’s hormones are sensitive to energy availability, meaning that too few calories or carbs can cause imbalances. Follow a healthy balanced diet you can maintain for the long-term.
  • Don’t yo-yo diet. It just messes with your metabolism and messes with your hormones, leaving a permanent mark. And you will probably wind up gaining the weight back and then some! So, pick a diet that is sustainable and healthy.
  • Eat mindfully avoiding distractions with 3 – 4 meals a day. Try to space meals at least 4 hours apart and don’t eat for at least 4 hours before bed.
  • Eat High fiber/high volume and low-density foods like veggies, fresh fruit, salads, broth-based soups, beans, legumes and whole grains.
  • Eat Healthy fats. Try to include at least a small serving of healthy fat with every meal, such as coconut or olive oil, avocado, nuts, seeds or fat found naturally in animal products like dairy, beef or eggs.
  • Eat more protein. Since protein helps control hunger and retain lean muscle mass, increasing your protein intake can help you eat less overall and keep your metabolism up. Include protein with every meal, like yogurt, grass-fed beef, wild fish, eggs, pasture-raised poultry, legumes and beans.
  • Increase your zinc. Load up on spinach, beef, lamb, seafood, nuts, cocoa, beans, mushrooms, and pumpkin to boost your leptin production.
  • Increase omega-3, lower omega-6. Eat (or take) more omega-3s by eating fish, grass-fed meats, or chia seeds) and minimize your omega-6 consumption (vegetable oils, conventional meats, grains, etc,) to get lower inflammation and help support healthy leptin levels.
  • Practice intermittent fasting. Various forms of intermittent fasting (like 16 hours fasting and 8 hours eating window), including alternate day cycling and time-restricted eating, have been associated with improvements in leptin sensitivity and help with fat loss.
  • Get Physically Active. High intensity workouts HIIT and weight lifting, give the hormone benefits of working out without the stress from excess cardio. Too much cardio (the endurance, long-lasting kind) raises cortisol levels, increases oxidative damage, causes systemic inflammation, depresses the immune system, and decreases fat metabolism. Aim for at least 30 minutes daily, but ideally more like 45–60 minutes. Make time for rest and recovery.
  • Detox. Remove toxins from your life as these are a stress on your body. Get rid of processed foods, commercial deodorants, and switch to natural cosmetics and cleaning products.
  • Spend time in nature. Get outside during the day, preferably barefoot on the ground, in mid-day sun with some skin exposed.
  • Manage Stress to Reduce Emotional Eating. Do at least one thing that relaxes you each day, such as exercising, going to the beach, meditating, praying, stretching or doing yoga, taking a bath with essential oils, reading, journaling or doing something social.
  • Have a Cheat Day. A cheat day is a once weekly, or sometimes once bi-weekly, day when you typically consume much more calories (especially carbs) than you normally eat. Cheat days are meant to be used as a helpful tool when you normally follow a very healthy diet. They work by increasing your calorie intake temporarily, which “tricks” your body into thinking it’s being overfed, causing an increase in your leptin levels.
  • Track progress. This helps you to keep accountable and know you are on the right track making progress. Progress is not just your weight but also how you feel.

Foods that increase leptin sensitivity (decrease leptin resistance) some examples are oatmeal, grapefruit, hot peppers, lean protein, fish, yogurt, green tea, broccoli, almonds, eggs, olive oil, turmeric, apples and sesame seeds.

Once leptin sensitivity is restored, taste buds shift into high gear, and there is much more pleasure in eating natural foods

Once you have regained your leptin sensitivity your appearance will change:

  • Hair and nails will improve in colour and looks, you will have less dead skin on your feet, your skin will get softer and tauter and you will have better colour.
  • Moods will change as well as your personality and thinking. You will become more mindful, things won’t upset you quite the same, and you will cope with moments that may previously have taken you over the edge.
  • Thoughts about food will be the biggest change as you begin to awaken a sixth sense and intuition about what you really should be doing for health.
  • Appetite changes, your carbohydrate and sweet cravings will go away, you will notice the amount of food you need decreases and your taste buds and smell will become more acute. Sleep and energy will also improve once leptin sensitivity is restored.
  • You won’t feel the cold quite as much; even though you will exude body heat your body temperature will be lower as the thyroid settles.
  • Migraines should decrease along with prolonged muscle soreness after exercise; your libido will also heighten.

Leptin resistant people

  • have uncontrollable cravings, especially sweet foods and refined carbohydrates
  • like to eat late into the night
  • are stress eaters
  • have weight gain around the middle
  • have an inability to reach a goal weight
  • are yo-yo dieters
  • have thyroid symptoms, and
  • have problems with fertility.

Leptin sensitive people

  • are less hungry
  • feel satiated very quickly
  • crave fewer sugary foods
  • have faster metabolisms
  • have more energy, and
  • retain the ability to burn fat efficiently.

In conclusion, The leptin science has only been unraveling since 1994, so there are a lot of unanswered questions. Leptin appears to have many functions that scientists are still exploring. The hormone plays a role in heart and bone health. We know that leptin is very important in keeping the immune system happy and that chronic inflammation occurs in the face of inadequate leptin signaling, and that’s part of cardiovascular disease.

Food and lifestyle are the ways to change from being leptin resistant to leptin sensitive – there are no drugs, there are no supplements, just good quality foods that our body evolved to eat and improved lifestyle habits.

Remember, this takes time and everyone is different so to figure out what works best for you, you should experiment and adjust your lifestyle depending on how you look, feel and perform.

The great thing is you have the ability to make the changes yourself, and all you have to do is make the required food and lifestyle changes and see and enjoy the abundant health.

References for further reading:

  1. Leptin and Leptin Resistance: Everything You Need to Know (2018) https://www.healthline.com/nutrition/leptin-101#leptin-resistance
  2. What is the hormone Leptin and how does it relate to my weight? (2018) https://healthjade.com/what-is-the-hormone-leptin-and-how-does-it-relate-to-my-weight/
  3. Leptin the Appetite Suppressor Hormone (2016) http://walkingoffpounds.com/leptin-the-appetite-suppressor-hormone/
  4. How to Fix Leptin Resistance to Control Weight, Cravings & More (2019) https://wellnessmama.com/5356/leptin-resistance/
  5. How to Turn On Your Fat-Burning Switch, Leptin (Your “Starvation Hormone”) (2017) https://draxe.com/health/leptin/
  6. 23 Foods That Increase Leptin Sensitivity (2016) https://medlicker.com/1038-foods-that-increase-leptin-sensitivity
  7. Do Very Low-Carb Diets Mess Up Some Women’s Hormones? (2020) https://www.healthline.com/nutrition/low-carb-and-womens-hormones
  8. Applied Functional Nutrition Course (2019), Module 1, Lesson 2, Your Relationship to Food.
  9. Changing Habits https://changinghabits.com.au/

Courses for further learning:

Introduction to Nutrition Course https://thenutrition.academy/introduction-to-nutrition-course/
Functional Nutrition Course https://thenutrition.academy/functional-nutrition-course/

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