What is Appetite Correction and Why Does Fasting Cause You to Feel More Satisfied?
When we eat constantly, our brain can become deaf to the hormone leptin which signals satiety. Fasting heals leptin resistance and puts our brain in touch with our satiety signals.
Summary:
When we eat constantly, our brain can become deaf to the hormone leptin which signals satiety
Healing leptin resistance can take a few weeks
When you are suddenly not able to finish your food even though you really liked it, you’ll know that appetite correction is kicking in
A cascade of magical changes occurs in your body when you give it a break from food. The cells get busy recycling their damaged and misfolded proteins which cleans them from the inside and causes them to function better, a process called autophagy. (If you’re new, click here for my post on autophagy).
Another amazing process that occurs is that hormone signaling in the body gets regulated which leads to appetite correction.
Before I was into fasting, I could eat enormous amounts of food and not feel full. My appetite signals were completely broken. Now, I regularly have a hard time finishing my plate, but NOT because I’m practicing self-discipline. I just can’t take another bite.
There’s a physiological reason that fasting causes your appetite signals to work again. I’ve talked a lot about the hormone insulin but today I’m going to introduce you to a new friend, the hormone leptin.
In 1994, Dr. Jeffrey Friedman and a team of researchers discovered that there was a nutrient sensor that signaled the brain to stop eating—a satiety hormone they named leptin. They found that the body releases leptin from the fat tissues when you’ve eaten enough, and this makes you feel full.
When the researchers discovered this, they were elated. They thought they had found the holy grail of diet pills. All they needed to do was bottle up leptin and give it to people who were overweight. The leptin would make them feel full, they wouldn’t even want to eat, and they would lose weight effortlessly.
But it didn’t work. Giving leptin to people who were overweight didn’t make them feel full and didn’t cause them to lose weight. Why? Leptin resistance.
What the researchers found was that an overweight person has plenty of leptin circulating to signal them to stop eating, but their brain can no longer hear the signal. Giving them more leptin only made them more resistant to the signaling. No magic diet pill was created.
Leptin resistance is similar to insulin resistance. Remember, insulin escorts sugar out of the blood and into the liver, the muscles, and the fat cells. When someone is metabolically healthy, the fat cells open up to receive sugar when they sense a small amount of insulin. Insulin resistance occurs when more and more insulin is needed to signal the fat cells to open up. This leads to the body raising insulin levels and becoming hyperinsulinemic, meaning, chronically elevated insulin.
Hyperinsulinemia makes you hungry all the time, cranky, hangry, craving carbs, and unable to go for more than 2 hours without carbs or sugar. It’s a miserable roller coaster; I’ve been on it. Depending on how severe the insulin resistance is, you may need to do a more extreme form of fasting. I found that alternate-day fasting knocked my insulin resistance and sugar cravings out of the ballpark. But others have had success with less radical measures.
Back to leptin resistance. The brain becomes desensitized when it is exposed to a high level of a hormone too often. When you fast, you give your brain a break from exposure to leptin, causing it to regain leptin sensitivity. Then, after you’ve eaten, your fat tissues will release leptin and your brain registers that you’ve had enough nutrients.
When this system is working really well, you find that you are sometimes physically unable to eat another bite. Congrats, your appetite has been corrected. It was a very odd feeling for me the first time I looked at my food and simply couldn’t finish it. But the thing I love about appetite correction is that you leave meals feeling fully satisfied. That is what food is meant to do, to satisfy, not leave you wanting more and more.
Healing leptin resistance can take months depending on how severe your resistance is. Longer fasts and avoiding snacks between meals will speed up the process.
If you’re new around here, make sure to check out the Quick Start Fasting Guide.
[This newsletter is for informational purposes only and is not designed as a substitute for medical advice. Talk to your doctor before beginning any dietary changes, especially if you are on medications for diabetes. Fasting while taking certain medications such as Metformin and especially insulin can lead to dangerously low blood sugars. If your doctor does not support fasting, search for a physician who will support your fasting journey. Fasting is not recommended for those pregnant, breastfeeding, or for children and teens still growing and developing. For those with diabetes, personal fasting coaches are available through TheFastingMethod.com. I receive no compensation or ad revenue for anything in this newsletter including links to books, videos, websites, coaching services, podcasts, or supplements.]
I’m loving these articles! You are a voice of reason amidst all the unhelpful, misleading advice out there.
“A cascade of magical changes occurs in your body when you give it a break from food. The cells get busy recycling their damaged and misfolded proteins which cleans them from the inside and causes them to function better, a process called autophagy.”
Great explanation of the process. So many people I know are following the old “eat multiple tiny meals all day long to keep your metabolism high” advice, so as a result, they keep insulin high all day long and most of the night too.
I lost 140 pounds doing alternate-day fasting while on Mounjaro, and now that I've been off that medication for six months, Alternate-day fasting has helped me keep the weight off.
Can fasting days be tough? Yes, but on the flip side, it allows me the flexibility to not worry about counting calories and enjoy my eating days.
Another benefit of fasting is it never fails that a life stressor or emotional event happens on a fasting day, giving me the option to notice emotions I might bypass with food.