The sneaky hunger hormone that can stall weight loss

Your body is pretty great at letting you know what it does and doesn’t need—and that includes food. Your stomach grumbles when you’re hungry and feels full when you’ve had enough to eat. And that’s where leptin comes in. Leptin is a hormone released by your fat cells, and it’s the MVP for signaling your brain (and then belly) when you’re full.  

Leptin also affects your metabolism. It helps you maintain a normal body weight by balancing what you eat and how your body burns through it. The discovery of leptin in 1994 opened new doors for obesity treatment. It also shed light on the fact that fat cells aren’t just, well, fat. They’re actually an active part of your endocrine system. 

Meet metabolic adaptation

So how could leptin be throwing a wrench in your weight care journey? For starters, research shows that when you lose 10% of your body weight, leptin levels can fall by as much as 53% through a process called “metabolic adaptation.” 

“When leptin drops so disproportionately, the signal to your brain and body is that it needs to eat and conserve energy,” explains Found’s Rekha Kumar, M.D., M.S. Unfortunately, this may cause you to overeat—even if you’re already getting plenty of sustenance—and your metabolism to slow. 

Frustrating? For sure! But metabolic adaptation is another important way your body protects itself from starvation. However, according to some studies, it can lengthen the amount of time it takes to reach your weight care goals.

In one trial, researchers looked at premenopausal women with high BMIs who had lost an average of 16 percent of their body weight over some five months. However, after dropping those initial pounds, it took them longer to lose additional weight due to metabolic adaptation. In fact, for each 10-calorie increase in metabolic adaption the participants had, the amount of time it took them to reach their weight-loss goals went up by a full day.

How obesity affects your leptin levels

On the other hand, too much leptin can also cause problems. When you have excess body fat, your body can pump out excess leptin, leading to a build-up and tolerance known as “leptin resistance.” That means your brain doesn’t respond to this hormone as it usually would—and you may not feel full or satiated. Leptin resistance can make you eat more even though your body already has enough fat stored.

Remember how we talked about your body’s “survival mode” during metabolic adaptation? The same idea applies to leptin resistance. Since your body doesn’t register that it already has enough leptin, it shifts into energy-conservation mode—and your metabolism slows. Unfortunately, while this happens, your fat cells continue to make more leptin, which furthers this vicious cycle. So you can guess what happens next: you’ll gain weight rather than lose it. 

Can you balance your leptin levels?

It’s complicated. Although leptin is both a driver of obesity and a major appetite suppressant, preventing and treating leptin resistance remains one of the biggest challenges in overcoming obesity.

You do have some options. “Although we are not directly replacing leptin, some of the medications Found prescribes can help, possibly by allowing the brain to respond to existing leptin better, or by reducing appetite through other signals,” explains Dr. Kumar. 

And you can work with your coach on two other lifestyle factors that impact leptin levels: your sleep and stress levels. Lack of Zzzs and too much angst in your life negatively affect your leptin metabolism. And that can lead to weight gain and even type 2 diabetes. So prioritize getting them dialed.

Oh, and one last thing: While it might seem like a no-win situation that the more body fat you have, the more leptin you have, and the less body fat you have, the less leptin you produce, there is a sweet spot. How do you hit that sweet spot? By following a slow-and-steady approach to losing weight, rather than trying to drop too much all at once. (Maybe not what you want to hear, but it’s honestly the best way to win at weight care!). Set realistic goals, go gradually, and give yourself time and space to develop healthy habits that support long-term success.   

About Found

Found is among the largest medically-supported weight care clinics in the country, serving more than 200,000 members to date. To start your journey with Found, take our quiz.