Leptin is a hormone secreted by fat cells, the body uses Leptin like a dipstick in car to help us measure, and regulate energy intake and expenditure.
Even though leptin was only discovered in 1994 it is regarded as one of the most important hormones when its comes to adequate function of the human body.
Leptin is a manager for many other hormones, and helps with the signaling pathways for sex hormones, thyroid hormones, pancreatic hormones and adrenal hormones as well. Sounds kind of important eh ?
The proper functioning of those hormones listed above require leptin, however it’s not a two way street, because leptin doesn’t require them for its function.
Problems with leptin signaling in the body are related to bone loss, immune and digestive problems, liver dysfunction, cognitive and nerve issues.
Both too much and too little leptin can cause dysfunction, we need our leptin levels like goldi locks needs her porridge… just right!
Since the discovery of leptin the idea of body fat as only a storage place on the body for excess calories has evolved into viewing fat more as an organ.
When leptin is secreted from the fat cells it communicates with the hypothalamus in the brain to regulate our body weight and fat stores.
Your Body Fights Your Fat Loss
While we all have our own idea of what a healthy or fit bodyweight is, your brain is only concerned with your survival and reproductive capabilities.
Your brain doesn’t care about you having abs, it wants to make sure you aren’t depleting those precious fat stores too much!
Body fat is a good insurance policy for ensuring your survival, and the brain gauges how much body fat we have based on leptin levels.
When leptin levels are normal the brain gets the signal that there is no need to eat more and store excess calories, and appetite is normal.
Leptin allowed our ancestors to survive when they encountered famines and food was scarce by lowering the metabolic rate.
As a response to famines fat stores would be broken down and used for fuel. As fat stores decrease so would leptin levels, signaling the body to slow the metabolism and conserve energy.
You body works more like a thermostat than a calculator meaning the body tries to match energy expenditure to the intake. If you eat less for long enough the body will burn less.
To restore leptin levels it takes a time frame dedicated to eating more calories and carbohydrates , and sending the signal that you are in a time of abundance.
Leptin is an important hormone when it comes to metabolic health because it adjusts your metabolism, endocrine function and behaviors to match the demands of your environment.
We now have the opposite problem of our ancestors, our food is too abundant and easy to obtain, while being extremely calorically dense.
This over nutrition creates a problem we haven’t encountered in mankind before, and leads to leptin resistance.
What Is Leptin Resistance ?
Almost all people who are overweight or obese have higher levels of leptin due to the fact that leptin is secreted from the fat cells.
Remember we want the goldi locks effect with leptin not too high or too low. When the brain gets bombarded with leptin constantly it will pull the receptors inside the cells.
When your brain pulls these receptors for leptin inside the cell it makes you leptin resistant meaning that the brain thinks there are no fat stores because it can not see the circulating leptin.
The brain will increase the appetite to help ensure we have adequate fat stores for survival, even if you have plenty of fat stores already.
The brain uses leptin like a fuel gauge showing how much fuel (bodyfat) we have in the tank of the car (body). The signals from leptin in the brain help to regulate the amount energy burned or stored.
Even when leptin levels are normal if the brain doesn’t receive the signal from leptin it will think there is not enough fat in storage, and increase appetite to refill stores.
This is the equivalent of having a car with a full tank of gas and broken gas gauge that’s stuck on empty. As a result you are constantly stopping the car to put gas in the tank even though it’s full.
The gas will overflow when you try to add more gas to the full tank. This is the equivalent of excess calories that aren’t needed becoming body fat because your brain thinks there aren’t enough fat stores, when in actuality there is plenty!
As always thanks for reading, and stay tuned for Part 2 of this series next week when we discuss the causes of leptin resistance, and how to avoid/reverse it.
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