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What Is Leptin?

Leptin is derived from the Greek word leptos which means slender, frail, or weak. The hormone was discovered in 1990 in genetic testing on obese mice by Rudolph Leibel and Jeffrey Friedman. This was the first adipokine ever discovered (adipokines are hormones secreted by fat cells that influence appetite, fat storage and systemic inflammation). Initially researchers and doctors alike were convinced weight loss was a simple problem; calories in vs calories out. If you eat more calories than you burn, you would gain weight. Conversely, if you eat less calories than you expend, you will lose weight. What could possibly alter this overly simplified view off human metabolism? Hormones! Hormones are the masters of our metabolic processes. These chemical signals over ride calories in the argument about weight gain or weight loss. How many times have we heard stories of people swearing that they are eating perfect, but their body just wont drop any weight? It comes down to hormonal cascades and issues that arise when they end up off kilter. This article will focus on leptin and it’s role in weight loss specifically. Let’s try to simplify this to easy to understand terms, not make this a lesson in biochemistry.

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What Does Leptin Do?

Simply put, Leptin signals your brain to say “you have enough body fat stored, you don’t need to eat!” The body then goes about burning calories at the normal metabolic rate for your body. Leptin also plays roles in fertility, immunity, and brain function, but those subjects are for another discussion. The role we are concerned with in this article is how it affects weight loss or weight gain. Leptin’s main role in metabolism is controlling our long term energy balance and how much body fat we store. This is what most people want to know about anyhow. Every single cell in the body is programmed to survive. So at the basic level, every component in our body is designed to survive. The role Leptin plays is to make sure the organism doesn’t over eat or under eat, both scenarios don’t bode well for long term survival. So, how does something so simple in function go off the tracks you might ask? Well here is how Leptin works in two simple scenarios.

  1. You eat -> body fat goes up -> more Leptin is secreted-> you eat less and burn fat.
  2. You don’t eat -> body fat goes down -> less Leptin is secreted -> you eat more and store fat.

This system is known as a negative feedback loop. An increase in one thing is met by a decrease in another and vice-versa. So what happens when this system falters and a person develops a condition known as Leptin resistance?

What Is Leptin Resistance?

Obese people not only have more fat cells than the average person, they also have a lot more fat stuffed into these cells. Because the fat cells release Leptin in relation to their size and number, obese people have very high levels of Leptin circulating in their bodies. Considering how Leptin works, these people should stop eating correct? There is a ton of Leptin floating in their bloodstream, this should be signaling the brain that they are full and don’t need to eat. The problem with Leptin resistance is that even though there is a plethora of it in the blood, the brain “can’t see it.” This is how obese people can get so large, like cases when you see gargantuan 600 pound plus people. The brain doesn’t see the Leptin signal, thinks that it is starving, and kicks hunger into high gear. It’s a very vicious cycle. The following shows how it works.

You eat -> your body stores fat -> your fat secretes Leptin –X–> your brain doesn’t see Leptin and thinks it is starving -> you keep eating and getting larger.

The end result is a two pronged problem. First, you are eating more and storing more fat because your body thinks it is starving. Secondly, your metabolism slows down and makes you sluggish, further causing more weight gain. However, eating more and exercising less is not the cause of the weight gain, it is a consequence of Leptin resistance. Trying to exercise willpower over a complex hormonal system is next to impossible. Leptin resistance is much like insulin resistance. The body has high circulating levels of a hormone, so to combat this, the Leptin receptors become desensitized to the signal. Once this happens, it is difficult to reverse.

What Causes Leptin Resistance?

Scientists have been trying to unravel the metabolic mess that is Leptin resistance. They have come to somewhat of a consensus regarding what is the root cause. So far, the main 3 theories are: 1) Inflammation- In both human and animal studies, inflammatory signaling in the hypothalmus results in Leptin resistance. 2) Free Fatty Acid Levels- Too much free fatty acids floating in the blood may cause fatty acid deposits in the brain resulting in interference of the Leptin signaling. 3) Having High Leptin Levels- Elevated levels of Leptin result in decreased sensitivity to the Leptin signal.

Leptin Resistance Makes Dieting Difficult

Most people who have dieted realize that long term success is the exception rather than the norm. Why is this the case? In simple terms, reduced fat mass reduces Leptin levels which results in increased hunger and a slower metabolism. Even though the levels of Leptin have decreased, the Leptin resistance doesn’t just reverse itself. The state you are left in is increased hunger, reduced motivation to exercise, and reduced caloric burning at rest. That is a pretty daunting triad of factors to overcome. When people start a diet, they are highly motivated and things go well, but pretty soon Leptin resistance rears its ugly head, cravings kick in and the desire to exercise is greatly reduced. So how do you know if you have Leptin resistance?

the size of stomach of children with overweight.

Signs Of Leptin Resistance And How To Prevent It

If you have a lot of body fat, specifically in the midsection, you are highly likely to be Leptin resistant. So the biggest tool in preventing this issue is the mirror. Much of the reason for Leptin resistance is due to an inflammatory diet. The average western diet is much to high in pro-inflammatory foods.

  1. Avoid processed foods-They compromise the health of the gut and increase inflammatory response.
  2. Eat soluble fiber- Fiber protects the gut and also protects against obesity.
  3. Exercise- Being active physically can reduce or even reverse Leptin resistance
  4. Get sleep- poor sleep increases stress, which increases inflammation, this increases Leptin resistance
  5. Lower Triglycerides- Lowering levels of circulating triglycerides can lower fat deposits in the brain. This prevents Leptin from enetering the brain and doing its job. To lower triglycerides, decrease carbohydrate intake.
  6. Eat protein- Protein can cause a decrease in Leptin resistance, thus promote weight loss.

Leptin Resistance: The Take Home Message

Leptin resistance is just one of the way biochemistry can destroy a persons ability to lose weight. Insulin, Glucagon, Ghrelin and a host of other hormones also play a role. The bottom line, when it comes to weight loss, there is no bigger player than Leptin. If you have your Leptin functioning properly, your body is likely in a good place physique wise. If your Leptin is not, it is likely due to the western diet. Everywhere this diet rears it’s ugly head, chronic disease is sure to follow. This isn’t because the diet turns people into slobs an over indulgers; it is due to how it alters biochemistry in a negative manner. To say Leptin is the only cause of obesity would be incredible shortsighted, but it is without a doubt, one of the main players in a cast of hormones. Get you Leptin under control and you are on the way to a much healthier body and a more pleasing physique. If you are having a hard time losing weight, buy our Cutting Meal Plan and our Cutting Workout to help you tackle your issues with Leptin.