What causes leptin resistance?
What causes leptin resistance? Leptin is a hormone secreted by the body’s fat cells and its main function is to regulate the appetite1. Therefore, it plays a key role in the development of obesity, medical, social, and economic problems in society. Leptin and its receptors are identified as pivotal for the regulation of body weight and for energy homeostasis. Similarly, even a minor deviation in the concertation of leptin causes appetite to decrease and an increase in body weight. However, the anorexic effect of leptin is decreased in cases of obesity, despite an increase in leptin concentration 2.
Leptin resistance develops because of a defect in the intracellular signaling linked with a decrease in the transport of leptin across the blood brain barrier3. Although there are still no clear criteria for defining leptin resistance and it is difficult to highlight the underlying molecular mechanism of leptin resistance. Most studies that examine the effect of leptin resistance are performed on mice with a defected leptin receptor gene, which is rare in humans.
This further complicates research on leptin resistance and identifying diagnostic markers. In addition, there are several questions that need to be answered when it comes to assessing leptin resistance. It also raises the question whether the presence of a high leptin concentration is adequate for establishing the diagnosis. Similarly, if leptin resistance should be defined based on a one-time increase in the concentration of leptin. However, there has been a significant increase in studies concerning leptin resistance because of its association with cancer, cardiovascular and autoimmune disease.
Leptin, the “satiety” or “starvation” hormone
Leptin hormone is commonly referred to as the “satiety hormone” or the “starvation hormone”. The main function of this hormone is to target the hypothalamus in the brain when you have enough fat stored and that you do not need to eat more. Hypothalamus is the part of the brain which controls how much you eat. Leptin has several other functions, including brain function, immunity, and fertility. Although the main role of the hormone is to regulate energy and the number of calories you eat and spend. Moreover, the amount of fat stored in your body. The leptin system is continuously evolving to keep humans from starving and overeating – both of which are necessary for survival in the natural environment. Leptin is very effective in keeping us from starving and overeating.
What impact does leptin have on your brain?
The more fat your body has, the more leptin your body’s fat cells will produce. Leptin is carried to the brain via the bloodstream where it sends a signal to the hypothalamus. These fat cells are using leptin to tell the brain how much fat your body can carry. High levels of leptin in the body will tell the brain that you have enough fat stores. Whereas low levels of leptin will signal the brain that there are low fat stores in the body and that you need to eat.
Your body fat goes up every time you eat, and this leads to your leptin levels also going up. Hence, you burn more. Likewise, your body fat goes down when you don’t eat, this causes your leptin levels to drop. At this point you are eating more and burning less. This system is referred to as the negative feedback loop. It is like the control mechanism of different physiological functions, for example, blood pressure, body temperature and breathing4.
What impact does leptin have on dieting?
Leptin resistance is one of the reasons several diets fail at long-term weight loss. If you are leptin resistance, losing weight does reduce fat mass but it also leads to a significant reduction in the levels of leptin. However, the brain does not reverse this leptin resistance. Decreased levels of leptin lead to an increase in appetite, a decrease in the number of calories burned and reduced motivation to exercise.
Your brain thinks that you are starving and triggers a mechanism to regain the lost body fat. This is one of the reasons why so many people on crash diets lose a significant amount of weight only to gain it back shortly after.
When people lose fat, the levels of leptin also drop significantly. The brain thinks that this is a starvation signal and changes your biology to make you regain the fat that is lost. The hormone plays an important role in regulating your energy expenditure. While more fat cells should mean more leptin causing hunger levels to shut down, it is the complete opposite. Leptin resistance is often common in people who are overweight.
What happens when leptin resistance develops?
When leptin resistance develops, signaling of leptin is also interrupted. So, no matter how much leptin is produced, the brain does not get the signal to stop eating. Instead of interpreting that extra leptin a sign to stop eating, the metabolic and endocrine systems read it as a starvation alert. Leading to an uncontrollable craving for foods high in fat and carbohydrates to increase the stores of fat. Leptin is ineffective to satiate hunger. Correcting leptin resistance can help with hormonal balance, controlling appetite and shedding stubborn pounds.
What causes leptin resistance?
Leptin resistance develops because of three factors: decreased sleep, increased stress and eating too much of the wrong foods. Other factors that may lead to leptin resistance include, excessive snacking, late night snacking and snacking on overly processed foods, simple carbohydrate and high fructose; little or no exercise; less exposure to the sun; yo-yo dieting; high stress; overload of toxins; increased intake of sugar; high levels of triglyceride; high levels of insulin and overeating.
These factors lead to a damaged endocrine system and metabolic function, causing leptin resistance. In addition, the factors that contribute to leptin resistance can also increase and become a symptom of leptin resistance, for example, overeating causes leptin resistance which then triggers overeating.
Symptoms of leptin resistance
How does one tell that they are suffering from leptin resistance? Here are some symptoms of leptin resistance:
• Uncontrollable food cravings, especially of high-fat and high-sugar foods.
• Inability to lose weight.
• Increased inflammation.
• Increased leptin levels.
If you think that you are suffering from leptin resistance, your healthcare provider will review your medical history and conduct a physical examination. After assessing symptoms, your healthcare provider may also advise a blood test to measure leptin levels. This will help confirm the diagnosis of leptin resistance.
What causes leptin resistance can you reverse leptin resistance?
Leptin resistance can be treated in various therapeutic ways, most of which are related to your diet. Following a leptin diet is the key to reversing leptin resistance and losing weight. While it may be difficult to control overeating with leptin resistance, controlling the types of foods you eat is the first step to heal your leptin resistance. An ideal leptin resistance diet should consist of omega-3 fatty acids and lean proteins.
Reduce the amount of omega-6 fatty acids, sugar, high-fructose corn syrups, refined processed foods and carbohydrates. Also, avoid snacking in between meals and increase the time between your meals in a day5.
• Cut down on processed foods: processed foods compromise your gut’s integrity and cause inflammation.
• Add soluble fiber to your diet: soluble fiber can help with improving your gut health and will protect you against obesity.
• Lower triglycerides: a diet high in triglycerides can hinder the transport of leptin from your blood to the brain. An easy way to reduce triglycerides from your diet is by eliminating carbohydrates.
• Add more protein to your diet: studies have shown that eating plenty of protein automatically causes weight loss. This may be because of an improvement in leptin sensitivity.
A few lifestyle components are also important to consider when it comes to combatting leptin resistance.
• Reduce stress
• Get more sleep. Poor sleep is implicated with leptin resistance.
• Exercise daily, focus on strength and resistance training. This will help reverse leptin resistance.
• Speak with your healthcare provider about supplements that may help with leptin balance and signaling.
What is the best way to know that you have leptin resistance? The best way to know is by looking at yourself in the mirror. If you have a lot of body fat, especially around the belly area then you are most likely suffering from leptin resistance. While it is not entirely clear how leptin resistance can be reversed, there are theories that have shown to be useful. Some researchers believe that following a leptin diet may help reverse the resistance.
However, an overall healthy lifestyle is also an effective strategy to reverse leptin resistance.
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2. Allison MB, Myers Jr MG. Connecting leptin signaling to biological function. The Journal of endocrinology. 2014 Oct;223(1):T25.
3. Banks WA. Role of the blood–brain barrier in the evolution of feeding and cognition. Annals of the New York Academy of Sciences. 2012 Aug;1264(1):13.
4. Schwartz MW, Woods SC, Porte D, Seeley RJ, Baskin DG. Central nervous system control of food intake. Nature. 2000 Apr;404(6778):661-71.
5. Izquierdo AG, Crujeiras AB, Casanueva FF, Carreira MC. Leptin, obesity, and leptin resistance: where are we 25 years later?. Nutrients. 2019 Nov;11(11):2704.