Leptin is a hormone produced by fat cells that was first discovered in 1994 by Jeffery Friedman. It’s the original “hunger hormone.” Like all hormones, leptin is a chemical messenger. When it comes to leptin, the message leptin sends is “I’m full.” Leptin is produced by fat cells, travels through the bloodstream, and then acts on the brain’s appetite centers, signaling feelings of fullness. When leptin levels are low, you feel hungry and motivated to search for food.
People with leptin deficiency are hungry all the time and very overweight. They can take leptin injections and lose a lot of weight without diet or exercise. The problem is that leptin deficiency is extremely rare. In my career, treating thousands of overweight and obese patients, I have never seen a case of leptin deficiency (nor have any of my colleagues).
So if leptin deficiency is so rare, why all the hype about this hormone? It turns out that most overweight or obese people have dysfunctional leptin. In fact, your fat cells produce large amounts of leptin. But since leptin is not working properly, the huge amount that is produced is still not enough to suppress appetite, making a person feel hungry all the time. Indeed, even if leptin levels are high, since they are not working properly, the body thinks that leptin is low. With leptin resistance, the brain doesn’t get the message that it’s time to stop eating, time to lose weight. Leptin resistance causes the brain to protect the body from perceived starvation, even in people who are profoundly overweight.
The following are symptoms of leptin resistance.
- Do you feel hungry all the time?
- Do you have unexplained weight gain?
- Is your weight slowly increasing over time?
- Do you have cravings for comfort foods, fast food, or high-calorie foods?
- Not hungry for breakfast or skipping breakfast?
- Do you overeat at dinner?
- Do you have excess body fat?
- Do you have unusual eating patterns or does your diet vary significantly from day to day?
- Does weight loss stop after losing only 5-10 pounds?
- Do you have insulin resistance, metabolic syndrome, prediabetes or diabetes?
- Do you have arthritis, asthma, lupus or allergies?
- Do you have high blood pressure or high cholesterol?
- Do you have bad sleep, interrupted sleep or short sleep?
If you answered “yes” to 3 or more of these questions, you most likely have leptin resistance.
Leptin resistance means your brain thinks you’re starving when the reality is quite the opposite. Dysfunctional leptin drives appetite and especially cravings for high-calorie foods and junk food. The brain is doing everything it can to avoid hunger.
Leptin resistance also causes lower metabolism and can lead to a host of other hormonal problems like insulin resistance, type 2 diabetes, polycystic ovary syndrome, low testosterone levels (in men), and thyroid problems.
How is leptin resistance resolved?
Next week, I’m going to show you ways to make your leptin work better and more efficiently so you can lose weight permanently.