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What Is Leptin & Leptin Resistance (From a Dietitian)

Isaac Robertson
Published by Isaac Robertson | Co-Founder & Chief Editor
Last updated: August 2, 2023

Leptin is a hormone that prompts your brain to stop eating when your body has enough energy stored.

From the Greek word Leptos meaning "thin," this fat-derived protein is also known as your "satiety hormone," "fat controller hormone," and "starvation hormone."

So, if you're still wondering why you can't trim belly fat after countless diet plans and workouts, you might want to stick around to learn more about what leptin is and how it can help you manage your overall body weight.

Let's dig in.

Quick Summary

  • Leptin is a hormone, which commands the brain to stop eating food when your body has had enough.
  • This hormone also helps preserve bone mineral density, reduce cravings, and also supports good metabolism.
  • Exposure to high levels of circulating leptins triggers a condition called leptin resistance.

Do Fat Cells Affect Leptin Secretions?

person pinching her stomach

Yes, fat cells affect leptin secretions because leptin is directly connected to body fat.

The fat cells or the adipocytes of white adipose tissues produce the hormone leptin in proportion to its size, then secrete them in the bloodstream.

Consequently, the more fat deposits, the higher the leptin level is expected to circulate in the blood.

But when fat deposits drop over time, leptin secretion is also likely to reduce.

How Does Leptin Work?

empty plate on table and a person's hand tied with a measuring tape

Leptin works mainly in body fat mass regulation.

The leptin secreted by the fat tissue travels through the blood and acts on the hypothalamus, which then maintains energy balance to maintain fat stores within a stable level.

Leptin also stimulates and counteracts the effects of other hormones to inhibit food intake.

Leptin counteracts the effects of an appetite stimulant hormone, Neuropeptide Y, by reducing Ghrelin secretion in the gut.

Conversely, leptin can also promote the production of the alpha-melanocyte-stimulating hormone (α-MSH), which acts in the hypothalamus to suppress appetite.

Does Leptin Play a Role in Food Intake?

mouth view of a lady eating an apple

Yes, leptin plays a significant role in the regulation of energy intake and body weight.

Studies show that low levels of leptin in the body can lead to uncontrolled hunger and weight gain.

Also, leptin involves other areas of our body.

Other Roles of Leptin

  • Heart - Leptin helps to curb your appetite, which may further lead you to lose fat mass in your belly. By maintaining a healthy weight, you also prevent the risks of chronic heart diseases.
  • Bone - Leptin helps preserve bone mineral density (BMD) by reducing osteoclast activity [1], the process of degrading bone to initiate rebuilding and remodeling. It also regulates osteocalcin [2], a protein that strengthens bone health.
  • Fertility - Leptin helps reduce cravings and supports good metabolism. These help to improve obesity, the leading cause of infertility. Promoting weight loss through regulating leptin concentration is a significant consideration for normal reproductive function [3].

How Do Leptin Levels Affect Body Weight?

black woman in gym clothes with measuring tape on her neck and holding a scale thinking

Leptin levels may affect body weight if they fall at a certain leptin threshold.

When the brain recognizes the leptin signal and senses that you have enough energy stores, your brain instructs your body to eat enough and burn energy at an average rate.

In cases where there is too much or too little amount of leptin in the body, potential problems and issues may arise.

Potential Problems of Leptin Deficiency

woman in a food coma with chips and pizza on table

The absence or deficiency of leptin makes the brain think it does not have enough fat stores.

This condition results in uncontrolled eating and severe obesity.

Also, when leptin levels decrease, it may cause problems, including delayed puberty and a poor immune system.

Luckily, the absence or too little leptin conditions are rare and may be treated with leptin injections.

It is seen in the cases of Congenital Leptin Deficiency, a hereditary condition in which the body cannot produce leptin, and Congenital Generalized Lipodystrophy, in which an individual has nearly no body fat to produce leptin.

Without leptin to reduce huge appetite and food cravings, it is even more challenging to lose weight.

Potential Issues of Too Much Leptin

stomach view of person pinching his belly fats

Excessive or too much leptin may happen to an obese individual.

Since they have extra-large fat deposits, they produce more leptin in the bloodstream.

In effect, the brain is constantly bombarded with satiety messages until the brain stops responding to these signals.

The brain then develops a lack of sensitivity to the hormone and becomes leptin-resistant.

What Is Leptin Resistance?

man holding up a big burger with his mouth wide open

Leptin resistance is a condition that has profound implications on obesity and metabolic dysfunctions.

Katie Tomaschko Tout, a registered dietitian and nutritionist, explains that if you are lacking leptin or are leptin-resistant, your body is not telling your brain properly that you are full/satisfied — thus presenting an easy possibility of overeating.

Individuals suffering from obesity have large deposits of fat cells in their bodies, equating to more leptin production.

Thus, increased levels of the hormone secreted bring constant leptin signaling to the brain.

When this happens, the brain develops an insensitivity to leptin signals, and the signaling pathway is disrupted.

The brain no longer receives the message and assumes that your body is starving.

So, leptin-resistant individuals continue to eat despite excess fat storage, thus accumulating more fat cells, and in turn, leptin levels rise but are unavailable for the body to utilize.

Related: How to Boost Your Leptin Levels?

What Causes Leptin Resistance?

table filled with junk food and sweets, and a man frustrated in bed

Hyperleptinemia or chronic exposure to high levels of circulating leptin [4] causes resistance to leptin.

Julianna Coughlin, registered dietitian and contributor at Ghostbed, explains that circulatory levels of leptin, a hormone that signals energy balance to the brain, are influenced by sleep duration. This then affects homeostasis which is affected by leptin levels.

Aside from insufficient sleep, this condition may also develop due to poor diet and lifestyle, undue stress, and inflammatory foods

Other factors also include having high triglycerides [5] and insulin levels [6].

Is Leptin Resistance Manageable?

Yes. If you are leptin-resistant, you can manage this condition by reducing the intake of inflammatory foods and focusing on an overall healthy lifestyle.

Some things you can do include: 

  • Preserve gut health. Eat foods rich in soluble fiber and avoid processed foods.
  • Lower triglycerides level. Get regular exercise and eat fewer carbs.
  • Maintain an ideal weight. Reduce insulin resistance to reduce fat cells and eventually cut your cravings short.

While getting rid of this condition may not be possible, making better choices every day may help you manage this condition.

Can Managing Leptin Levels Help in Overall Body Fat Loss?

Yes, managing leptin levels can help you lose overall body fat.

Leptin can be friendly and help you reduce food intake by curbing your appetite, burn more calories by increasing metabolic rate, and support normal weight loss by controlling your energy expenditure.

So, if you want to get rid of the risk factors of belly fat, you might want to work on your levels.

With a healthy lifestyle and diet, supplements to boost your workouts, you can put those hormones back in balance.

Regaining your health is essential and a better quality of life is waiting for you today.


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