5 Facts About Leptin: The Fullness Hormone

Did you know that stress, along with restrictive diets, can change the functioning of the fullness hormone so it doesn’t work like it should? As a result, you may actually end up eating more.
5 Facts About Leptin: The Fullness Hormone
Valeria Sabater

Written and verified by psychologist Valeria Sabater.

Last update: 15 December, 2022

Leptin is the principal fullness hormone. It’s in charge of sending out a series of messages to your brain that tell it that you’re already “full” and no longer hungry.

However, it’s not as simple as it may at first seen. That’s because appetite isn’t the same as hunger.
Appetite is an emotional desire. Because of this, it can’t always controlled by this hormone. Instead, cognitive mechanisms, perceptions, and especially emotions, are deeply involved in appetite habits.

On the other hand, what we define as “hunger” is a physiological need. It’s used to fill your nutritional needs, which then allow you to thrive.

Obviously then, you should eat when you’re hungry.

Your body needs a variety of nutrients. It uses these to maintain cellular structure and function. They also give you energy. When you get these nutrients, hunger hormones like leptin work as well as they can.

As a result, we’ll take a look at some more information on the principle fullness hormone. You’ll also see how you can “take care” of it. These good habits will keep it in good working order.

1. Leptin: the fullness hormone that’s abundant in overweight people

People who aren't overweight have less leptin than those who are overweight.

This interesting statement may have grabbed your attention. If leptin is the fullness hormone, how can it be that overweight people have it in excess?

Let’s take a look at some data to understand this:

  • Leptin is a hormone that’s mainly produced by adipocytes (fat cells).
  • This is what’s known as a “signal hormone”. In other words, it communicates with your hypothalamus to tell you when you need to stop eating after it realizes that you’ve already gotten enough fat from the food.
  • Now, what happens with people who are overweight is that they suffer from a leptin resistance.
  • Obese people have very high levels of leptin in their blood. In other words, it accumulates without acting like it should.

Because of this, it’s normal to take longer to feel full.

There’s another problem that might increase your resistance to leptin. This is if you have a problem with your hypothalamus. This causes you to lose your sensitivity to this hormone.

What can you do to reduce leptin resistance?

  • Avoid inflammatory foods
  • Eat foods with good fats: olive oil, salmon, avocados, etc.
  • Sleep between 7 to 9 hours per day
  • Exercise on a regular basis

2. Leptin, the fullness hormone, has many other functions

This woman is stressed because she's hungry, so she needs the effects of leptin.

We already know that one of the uses of this hormone is to send signals to your hypothalamus to tell it that you’ve gotten enough energy. It then tells you to stop eating because you’re full.

However, this protein also has other functions:

  • It inhibits the production of other hormones and other peptides that increase your desire to eat. This is the case with neuropeptide Y.
  • It’s also interesting to note leptin increases your caloric and metabolic usage. In other words, it accelerates your metabolism so that you lose weight or get rid of the excess fat you have.

3. Strict diets reduce your leptin levels

People who follow very strict diets reduce the activity of the principal fullness hormone.

  • Because of that, diets that require a low level of calorie consumption – the so-called “miracle diets” – aren’t really so great.
  • As your levels of leptin fall, your metabolism becomes slower and your hunger becomes more intense. Your body’s energy levels also fall.

4. Stress can make you gain weight because of leptin

The functioning of leptin an be improved with exercise.

We know that there are people who lose weight when they are going through a very stressful time. However, it’s common that those who go through “chronic stress” have the opposite happen to them.

The reasons for this are explained below:

  • A greater amount of stress means a greater amount of cortisol in your blood.
  • The more cortisol you have, the more leptin’s presence is reduced.

As a result, what happens is something that a lot of people know: you get hungrier, enjoy eating more, and use less energy.

5. Is leptin the best remedy for losing weight?

It’s very likely that more than one person reading this is thinking about how to increase the effectiveness of leptin. This would make you feel full earlier and eat a lot less.

Also Read: Tips for Eating Less

  • It’s worth mentioning that the fullness hormone works in sync with your brain.
  • As a result, it would never give a signal to stop eating when you need more nutrients and energy.
  • If it did, it would be working against your health and that wouldn’t be good.

With all this information, we want to make something very clear. It isn’t good to buy dietary supplements that say that they have leptin to reduce your hunger. Also, it isn’t good to follow diets that are too strict.

If you suffer from being overweight, you should talk to your doctor. This way you can determine whether there’s a hormonal problem behind it.

Also, if you really want to take care of your leptin levels and their proper functioning, don’t wait to change your diet. You should also exercise and manage your stress and anxiety appropriately.

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All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.


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  • Botella Carretero, J. I., Lledín Barbancho, M. D., Valero González, M. a., & Varela DaCosta, C. (2010). Leptina: implicaciones fisiológicas y clínicas. Anales de Medicina Interna. https://doi.org/10.4321/s0212-71992001000300012

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.