What is leptin?

Many believe that gaining and losing weight is all about calories and willpower. Yet modern obesity research disagrees, and scientists seem to argue that a hormone leptin is heavily involved in this process.

Leptin resistance is a condition where the body no longer responds to this hormone. It is now considered the primary driver of fat gain in humans.

This article provides an update on everything you need to know about leptin, and how it is involved in obesity.

Leptin and the regulation of body weight

Leptin is a hormone produced by our fat cells. It is also called ” hormone of satiety” or “hormone of hunger”.

Leptin is mainly absorbed in the brain, particularly in an area called the hypothalamus.

Leptin is believed to express to our brains, when we have enough stored fat, that we don’t need to eat and can burn calories at a normal rate.

La leptine, l'hormone de régulation de la faim

It also has many other functions related to fertility, immunity and brain function.

However, the main role of leptin is the long-term regulation of energy: the number of calories that we consume and expend, as well as the amount of fat that we store in our body.

The leptin system evolved to prevent humans from starving or overeating, which would have made us less likely to survive in the natural environment.

What is leptin resistance?


Given the way leptin is supposed to work, many obese people should naturally limit their food intake. In other words, their brains should know that they have a lot of stored energy. However, their leptin signaling may not work . Although leptin is present in plenty, the brain may not see it.

This disease, known as leptin resistance , is now thought to be one of the major biological factors in obesity.

When our brain does not receive the leptin signal, it mistakenly thinks that our body is starving, even if it has more than enough stored energy.

The impact of leptin on diets

L'impact de la leptine sur les régimes

Leptin resistance may be one of the reasons many weight loss diets are ineffective. Losing weight still reduces body fat, resulting in a significant reduction in leptin levels. But the brain does not necessarily reverse its resistance to leptin.

When leptin levels are low, our hunger increases. But that’s not all. Our motivation to move collapses, as does the number of calories we burn while at rest!

Our brain then thinks we are starving and initiates various powerful mechanisms to regain that lost body fat.

This leptin function could explain why so many people yo-yo: they lose a lot weight and regain it soon after.

What are the causes of leptin resistance?

Several potential mechanisms of leptin resistance have been identified.

  • Inflammation : Inflammatory signaling in the hypothalamus is likely an important cause of leptin resistance in animals and humans.
  • Free fatty acids : Too much free fatty acids in the bloodstream can increase fat metabolites in the brain and interfere with leptin signaling.
  • Elevated Leptin Levels : Naturally elevated leptin levels can cause leptin resistance!

Most of these factors are amplified by obesity, which means you could be trapped in a vicious cycle: you gain weight and become more resistant to the leptin over time.

Can leptin resistance be reversed?

The best way to tell if you are leptin resistant is to look at yourself in a mirror. If you have a lot of fat on your body, especially on the midsection, then you are most definitely leptin resistant.

Reversing leptin resistance is still a little-known mechanism, although theories abound.

Some researchers suggest that the reduction in inflammation induced by diet may help reverse leptin resistance.

Suis-je résistant à la leptine ?

Focusing on a healthy lifestyle is also likely to be an effective strategy.

How to increase your sensitivity to leptin?

  • Avoid processed foods : Highly processed foods can compromise the integrity of your gut and cause inflammation.
  • Eat soluble fiber : Eating soluble fiber can help improve your gut health and protect you against obesity.
  • Exercise : Physical activity can help reverse leptin resistance.
  • Sleep better : Lack of sleep is linked to leptin problems.

Lower your triglycerides : Having high triglyceride levels can prevent leptin from being transported from your blood to your brain. The best way to lower triglycerides is to reduce your carbohydrate intake.

Eat protein : Eating lots of protein encourages automatic weight loss which may lead to improved leptin sensitivity.

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