Leptin resistance is similar to insulin resistance and they go hand in hand. When you have one, you typically have the other and it can be a major contributing factor to sugar addiction, carb addiction, food addiction, compulsive overeating, type 2 diabetes and obesity.
Leptin is a hormone that is produced in the fat cells and helps regulate hunger by providing us with feelings of satiation after we eat via the hypothalamus. It works in tandem with another hormone called ghrelin.
Ghrelin is a hormone released in the stomach by endocrine cells that stimulates hunger. It increases before meals to signal us to eat and decreases after meals to reduce hunger.
So in other words, ghrelin is your hunger hormone, leptin is your satiety hormone. One says I'm hungry and the other says I'm full. They work together to maintain homeostasis. Leptin decreases the production of ghrelin and tells you your full.
Ghrelin is released to tell your brain your hungry and then leptin is released to say you've had enough. Leptin also tells your body when to burn more fat and reduce storage of fat.
Insulin decreases ghrelin and increases leptin. When you eat sugar and carbohydrates that break down into sugar this stimulates insulin. Therefore ever time you eat sugar and carbohydrates then insulin stimulates leptin. When all goes as it should, then the appetite is reduced at this point. However when you eat sugar and carbohydrates this results in insulin levels that are too high then you also have high levels of leptin.
Just like neurotransmitters and insulin, the leptin receptors become unresponsive when they are overtimulated on a continuous basis and leptin resistance develops. Leptin is circulating in the blood, but the brain never receives the message from leptin that energy is sufficient and it doesn't need anymore food, so you remain hungry and crave more sugar and carbs. Leptin is not available to reduce ghrelin, thus hunger doesn't turn off.
Additionally, the consumption of fructose (high fructose corn syrup, table sugar, honey, fruit), plays a powerful role in this condition as well, as it directly results in an increase of ghrelin and a suppressing of leptin.
You should be able to see how this process is not only involved in sugar addiction, but compulsive overeating, food addiction and obesity. Obese people are found to have high levels of leptin in their blood, but it is not performing its job - leptin resistance.
Ghrelin actives the reward center in the brain and the neurotransmitter dopamine and although the mechanism of action is not completely clear yet, research indicates that leptin has at least some role in modulating endocannobonoids, which are similar to endorphins, and dopamine. These neurotransmitters are highly involved in feelings of joy, happiness, pleasure and well-being and result in numerous symptoms like cravings for carbs and sugar when they are not functioning as they should.
Additionally leptin has been found to target receptors on your tongue and serve as a modulator for sweets. Thus when there is enough leptin desire for sweets will be reduced, but if there is not enough leptin then cravings for sweets will ensue. When there is leptin resistance and the receptors are not responding, then cravings for sweets develop.(mercola)
In an interview with ABC news, Dr Mehmet Oz stated the following: "sugary foods affect the pathways to the brain in the same way as heroin or cocaine. Sugar acts directly in the brain to inhibit the effect of leptin and increased appetite so you never feel full. So then you keep eating, and you become leptin-resistant."
A vicious cycle ensues, sugar and carbohydrates lead to leptin resistance and insulin resistance which results in more cravings for sugar and carbs, which leads to more insulin and leptin resistance. To break this cycle, the sugar and carbs have to be eliminated.
Reversing or Preventing Leptin Resistance
Just like insulin resistance, the key to preventing or reversing leptin resistance lies primarily in the foods you eat.
Since it is sugar and all the foods that break down into sugar that cause a rise in an insulin and leptin, then it is these foods that must be eliminated. Naturally, avoiding the sugar and junk food, but also the high-starch, high carb, complex carbohydrates like whole grains, potatoes, corn etc. Become familiar with the Gylcemic Index and stick with foods that are lower than 40, as these are the foods that won't cause a spike in insulin levels.
All the elements required to keep leptin, ghrelin and insulin in balance and working effectively are integral to the Paleolithic diet, the diet that you are genetically coded to eat. This includes an abundance of organic, grass-fed or free range lean meats, fish, eggs, and low-starch vegetables, and a small amount of nuts, seeds and low-sugar fruit.
One other factor you should note is that lack of adequate sleep leads to an increase in ghrelin, the hormone that says I'm hungry, and a decrease in leptin, the hormone that says I'm full. So getting that eight or nine hours sleep each night is another important component of overcoming cravings for sugar and carbs, as well as maintaining weight.
Marcelle Pick, OB/GYN NP
Professor Loren Cordain - The Paleo Diet
Dr. Joseph Mercola