• March 8, 2018

Understanding Appetite – Grehlin and Leptin

Understanding Appetite – Grehlin and Leptin

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Understanding Appetite – Ghrelin and Leptin


Have you ever been sitting at your desk at work, out shopping, or catching up with friends and suddenly your stomach becomes vocal? There can be cramping sensations, they may leave you feeling sick, it may be something you can completely brush off, such repercussions may be significant enough to influence your mood. I am of course talking about hunger. For something as universally experienced as hunger I believe it is safe to say that the main underlying factors that can affect your appetite go wildly unknown. With 63% of the Australian adult population being classified as overweight or obese in 2013 and with overeating being arguably the most proximal cause of obesity, it is evident as to why having some general knowledge on the contributing factors to appetite is important. When considering your appetite, there are multiple influential factors, of which all lend to the overall sense of hunger/satiety. The factors I believe of the greatest relevance, the factors that will be today discussed in further detail include the number of calories you consume in a day, the sources you derive such calories from and the secretion of particular hormones that influence the function of specific neurotransmitters, subsequently either encouraging or discouraging the consumption of food at a given time. It is important to mention that even with a greater understanding of appetite and its regulation, you sadly won’t become immune to hunger, however ideally, you’ll have the tools needed to avoid periods of greater hunger and a greater understanding as to how to manipulate and influence the hormones that are at the origin of such sensations.

Ghrelin: Ghrelin is a peptide hormone both produced and released by cells of the stomach. It sends hunger signals to the hypothalamus in the brain to trigger the sensations we are all familiar with when our appetite rises. When the stomach is empty ghrelin is absorbed, and when the stomach is full, the secretory process is inhibited. Ghrelin is also produced in the presence of cortisol, which is why there is a tendency amongst some people to binge eat when stressed. Ghrelin is also believed to play a role in how quickly our appetite returns after a meal. Simply put – Increased ghrelin = Increased appetite.

Leptin: Leptin is in many ways can be considered the “anti-ghrelin”, Leptin is a peptide hormone, produced and released by adipocytes (fat cells) that suppresses appetite, by sending signals to the brain that the body has adequate energy stores, such as body fat, and current content of the stomach/digestive system. An important side note here is, much like with diabetics and insulin, an overweight person, even though they have plentiful stores of energy in the form of adipose tissue, can be unresponsive to leptins appetite suppressing effects, due to constant higher levels of exposure. The lessening effects of constant high levels of leptin on appetite suppression, is why we do not see Leptin as an available supplement to treat obesity. Recent research has also suggested that Leptin may play a more significant role in the bodies overall energy balance, than its counterpart ghrelin.

Adequate Calories / Volume dense Foods: I am sure it is no major surprise to anyone to see food on the list of ways to decrease appetite, as eating is the signal we are being sent to do, however as with most diet related topics, there is always a more efficient and effective approach. Firstly, if you are in a drastic caloric deficit and you are feeling very significant sensations of hunger, sometimes increasing calories is one of the only ways to get around it but be mindful I am talking about the reckless 1000+ calorie deficits some people put themselves through. Now, as discussed briefly when introducing Ghrelin (the hungry hormone), Ghrelin secretion is inhibited when the stomach is full, how this is achieved is by the “stretch reflex”, which occurs when the stomach is literally stretching from the food one eats, providing the hypothalamus with a signal to decrease food intake. Eating volume dense foods, that are low in calories, is by far the best method to activate the stretch reflex in your stomach, without over eating or consuming calorie dense foods that will quickly leave you wanting more food.

Water: It is of surely no surprise, that when dehydrated our bodies don’t function the way we intend to, after all, we are approximately 80% H2O. Not only is adequate hydration essential for almost all cellular process’ to take place, hydration also has a direct impact upon appetite. Experiments and studies have theorized that consuming water before meals helps to decrease an individual’s appetite by adding to the total contents and volume of the stomach, aiding in triggering the stretch reflex.

Chromium Picolinate: As with most things in science, the direct mechanism of action is debated and currently not 100% understood, however there have been countless studies that attest to Chromium Picolinate’s ability to attenuate weight gain. Studies comparing individuals taking Chromium picolinate vs a Placebo, with all other variables controlled, have consistently found there to be a direct link between Chromium picolinate supplementation and decreased hunger, decreased fat cravings, and decreased overall bodyweight. The even better news behind this supplement, is that it is relatively inexpensive, when compared to other supplements on the market, that claim to “burn fat”.

Appetite is a complex and often misunderstood concept, beneath the surface of what was presented today, there is a plethora of biochemical and nutritional science concepts that goes into truly understanding how our body regulates appetite, however having a general understanding of ghrelin and leptin, and other factors that can contribute to hunger/satiety can prove to be advantageous, especially to the health-conscious individual looking to either decrease or increase their weight. From increasing the volume of one’s meals to help trigger the stretch reflex in the stomach lining to decrease ghrelin levels, to ensuring adequate hydration for all cellular process’ to take place, there are multiple avenues one can simultaneously take when looking to gain a greater control over their appetite. It is important to mention that even with appetite regulation, the deciding factor upon weight gain/loss in the end will always inevitably boil down to overall caloric consumption, however of course, assuming one’s nutritional needs are being met and accounted for, should they apply the information provided today, they will be in the best position to truly take their composition goals to the next level, as the caloric restrictions will become easier to handle through greater satiety.