Metabolism
Overweight and Hunger Cravings
Leptin is your body's satiety hormone—and when it falls out of balance, hunger cravings and weight gain follow. Learn how to restore your leptin system to equilibrium.
Metabolism
Leptin is your body's satiety hormone—and when it falls out of balance, hunger cravings and weight gain follow. Learn how to restore your leptin system to equilibrium.
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Have you ever dieted and then experienced terrible hunger cravings after a while? And after your weight dropped nicely at first, did you eventually see the same number on the scale every day? Eventually you gave in to your hunger, and since then you've even gained 2–3 kilos. Even though you're not eating that much?!
Overweight is also a widespread phenomenon in Switzerland. Here's how this happens and what you can do about it.
The Master Metabolic Hormone
Leptin is a satiety hormone produced in fatty tissue. The more body fat, the more leptin is produced. In this way, leptin serves the brain as a kind of body fat sensor.
Beyond this "long-term component," there's also an acute one: high energy availability and strong insulin signaling also stimulate leptin production in fatty tissue!
Leptin works, among other ways, by binding to specific receptors in the hypothalamus, the brain's command center. This is where energy expenditure and energy intake are controlled.
When the body has enough stored fat—that is, when the body's energy status is in the green—a lot of leptin is produced. This in turn ensures that excess energy is burned through various processes. At the same time, further energy intake is reduced.
Leptin gives us
That sounds wonderful!
So what's the catch? Let's look at what happens when the leptin system goes off the rails in one direction or another.
Scenario 1: Leptin Resistance
Someone who is overweight (= has a lot of fatty tissue) has high leptin levels. In theory, this person should experience the leptin effects mentioned above—that is, have no hunger and burn their excess stored energy.
To a certain extent, that's even true, which is why the body resists further fat gain as fat mass increases. But this mechanism can be overtaxed…
Then the opposite happens: overweight people suffer from intense hunger cravings. This is due to what's called leptin resistance.
This means: leptin is high, but it can no longer work. We know this from insulin resistance (insulin high, but effectiveness poor).
Several causes are discussed for this, such as reduced leptin transport across the blood-brain barrier due to high leptin levels or excess triglycerides.
But also low-grade inflammation—that is, chronic inflammation triggered partly by overweight itself—can reduce the sensitivity of leptin receptors and thus cause resistance. And: there's evidence that wheat protein gliadin also inhibits the binding of leptin to its receptor.
This creates a vicious circle: the overweight person no longer has an adequate feeling of satiety and thus tends to gain more weight.
Scenario 2: Leptin Deficiency
Ironically, a well-trained bodybuilder in a cutting phase with 5% body fat can suffer from the exact same reason as an overweight couch potato—intense hunger cravings, lack of energy, and low libido.
It can also happen in very athletic, slim people that leptin doesn't work, this time due to too little leptin.
Excessive exercise and radical diets cause leptin levels to drop faster than you lose body fat. This is probably a protection mechanism in the body to preserve valuable fat reserves in case of starvation.
If you maintain too large a calorie deficit for too long, you reduce your leptin levels and thus your metabolism. When you raise calorie intake again after the diet, the dreaded yo-yo effect sets in.
The body is still in "energy-saving mode" and happily stores everything as fat. It doesn't check whether you're in a life-threatening famine—it just thinks you want a six-pack ;-)
Sleep deprivation has a similar effect, by the way: short sleep duration is associated with reduced leptin and elevated ghrelin (hunger hormone), and thus with increased appetite. The authors of the relevant study come to the following conclusion:
"Habitual sleep duration of less than 7.7 hours was associated with elevated BMI."
Let Leptin Work
By now it should be pretty clear what needs to be done to enjoy leptin's effects.
A healthy body fat percentage—neither too high nor too low—is worth striving for. With overweight, this is initially difficult due to the vicious cycle of leptin resistance mentioned above.
A first step would be to switch your diet to unprocessed, protein-rich foods and reduce inflammation, for example with Omega-3 fatty acids.
You should also choose a moderate calorie deficit during diets (300–500 kcal) and include regular refeeds—individual meals or entire days where you eat more, especially more carbohydrates.
Try to adjust your leptin balance so well that you don't need a leptin boost from McDonald's. Instead, through adequate energy and carbohydrate availability, you'll produce enough leptin on your own to feel properly satisfied.
And finally: get enough sleep (at least 7 hours) to prevent leptin levels from dropping.
Let's sum up: work with your biology, not against it. We need to understand that our body uses these mechanisms only to protect us. If you regularly give it the signal that it's safe (enough calories, enough sleep), weight loss will follow.
Schienkiewitz, A., Kuhnert, R., Blume, M. & Mensink, G. B. M. Overweight and obesity among adults in Germany – Results from GEDA 2019/2020-EHIS. *J. Health Monit. *7, 21–28 (2022).
Banks, W. A. et al. Triglycerides induce leptin resistance at the blood-brain barrier. *Diabetes *53, 1253–1260 (2004).
Gruzdeva, O., Borodkina, D., Uchasova, E., Dyleva, Y. & Barbarash, O. Leptin resistance: underlying mechanisms and diagnosis. *Diabetes Metab. Syndr. Obes. Targets Ther. *12, 191 (2019).
Jönsson, T. et al. Digested wheat gluten inhibits binding between leptin and its receptor. *BMC Biochem. *16, 3 (2015).
Landt, M., Horowitz, J. F., Coppack, S. W. & Klein, S. Effect of short-term fasting on free and bound leptin concentrations in lean and obese women. *J. Clin. Endocrinol. Metab. *86, 3768–3771 (2001).
Chin-Chance, C., Polonsky, K. S. & Schoeller, D. A. Twenty-four-hour leptin levels respond to cumulative short-term energy imbalance and predict subsequent intake. *J. Clin. Endocrinol. Metab. *85, 2685–2691 (2000).
Taheri, S., Lin, L., Austin, D., Young, T. & Mignot, E. Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index. *PLoS Med. *1, e62 (2004).
