Im writing this article today to talk about a certain hormone that despite its significant role in weight management, ill bet you havent heard of it before.
This article is Part I which will talk about Leptin, different factors affecting it and how it influences fat burning as well as appetite control.
What is Leptin?
Leptin is a hormone found in fat cells. It’s name is derived from the Greek name ‘Leptos’; meaning thin. It is responsible for many functions such as maintaining your immune system’s health, reproduction, stress, etc.
Any hormone functions as an initiator of a response, meaning that every hormone produced in our body is responsible for initiating an action. They are released into the blood stream and transported to their appropriate channel in another location in the body. Now let’s see what Leptin does in terms of weight management.
After consuming a meal, depending on the amount, macronutrient make up and other factors, Leptin is first released into the blood stream (from the fat cells) and is directed to your brain where it’s channeled through Leptin Receptors. Once it reaches its destination, it tells your brain that you are full and that your body has adequate energy levels.
Think of Leptin as a “messenger”. Upon receiving the message, your brain reacts by managing ghrelin levels (Another hormone that affects your appetite as well as satiety feeling) and influencing other chemical reactions that control your metabolism.
So Leptin lets your body know that you are fueled up and not at a risk of starvation, which allows the body to use your fat stores as energy.
Another way to look at it is your car’s fuel gauge. Leptin is the level of fuel (fuel indicator) displayed on your dashboard. By reading your fuel level, you either keep driving knowing you have adequate energy for your destination or fuel up if you don’t have enough fuel. That’s exactly how Leptin works.
You rely on the indicator because you can’t physically see the level of fuel in your tank.
If I’ve lost some of you, here’s a recap;
– Leptin is a hormone found in fat cells (the amount of Leptin is proportionate to your body’s fat levels)
– Simply put, Leptin functions as a “messenger” to regulate appetite and other chemical reactions influencing fat storage and metabolic rate by telling your brain that you have adequate energy levels.
– Leptin Levels fall as calories are restricted and in turn slow down metabolism and increase appetite.
Leptin Levels and Body Fat Level
Let’s now take a look at how different fat levels affect the signals sent to your brain.
Leptin Levels have a direct linear relationship to the amount of fat you carry. I.e. the more overweight you are, the more Leptin is released. That should be a good thing.
In an ‘IDEAL’ world, the more Leptin you have, the more signals sent. Thereby telling your brain to decrease appetite, increase fat metabolism and stop sending out hunger signals.
Reality however begs to differ. If Leptin levels are high, you should feel fuller & theoretically burning more fat. This brings me to the next issue of the dreaded “Leptin Resistance”
People who are overweight do have high levels of Leptin. The level though is not the issue.
Higher levels of Leptin should allow optimal fat burning and appetite control which is usually the opposite with people who have weight issues and that’s due to the fact that they have become Leptin resistant.
This means that even though there is an abundant supply of Leptin, it’s not doing the job it’s supposed to be doing. This happens for the following reasons;
– Desensitizing of Receptors
Overweight people tend to constantly overeat which leads to a constant surge of Leptin being released into the bloodstream and eventually to the brain through the Leptin receptors. Sensing the latter, the brain thinks that there is a problem and in turn shuts down the receptors. As a result, you have high levels of ‘circulating Leptin that doesn’t serve its purpose.
To better understand, think of what happens when you place a glass under a running tap (where the water = Leptin). Once the glass is full, its starts to overflow surpassing the cups capacity and in turn you cover the top of the glass. Even though the tap is still flowing (Leptin released) the water is not getting into the glass but rather spilling around (i.e. not serving its purpose). So instead of being full, you’re saying “Pass them cookies that-a-way!!”
– Insulin Resistance
Insulin resistance is the condition where your body creates insulin but is unable to use / allocate it. Your body becomes resistant to insulin (which as we know is converted into glucose for energy) which causes you to store it as fat.
Insulin resistance is thought to inhibit the function of Leptin.
– Pleasure center of the brain
Your brain, amongst other things is responsible for releasing pleasure hormones that give you that “good feeling”. These hormones can override Leptin’s signal of feeling full.
Ever felt full yet at the sight of cake or chocolate completely regained your appetite? Chocolate is believed to make the brain release those “feel good” hormones like endorphins and opiates.
It has been proven that just thinking of food kick starts chemical responses in the body. So, just thinking of chocolate for the matter will cause the release of those hormones and thereby overriding the message of Leptin.
Now that you’ve understood Leptin and its implications, you can see how adequately managing Leptin levels can either help or stray you away from your goals
In part II, I will talk about different strategies to manipulate Leptin levels while dieting and ways to manage Leptin Resistance.
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