The Appetite Regulating Hormones

One common trait exhibited by a great majority of overweight individuals is that they have a somewhat uncontrollable appetite and tendency to engage in overeating. Although the general opinion has been that such individuals lack a degree of willpower, science is however now indicating that it may have a lot more to do with hormones.

Generally, being hungry is a fundamental part of human physiology but which tends to take on an entirely new dimension when dieting. For its survival and optimal performance, the human body has a very efficient pair of hormones that helps the brain to know when the body needs to eat and when it has eaten enough. People generally tend to overeat when the brain either does not receive the relevant signals from the respective hormones or fails to properly interpret them.

There are two hormones namely leptin and ghrelin which are responsible for letting the brain know when the body is hungry and needs to eat or otherwise. These hormones are what control our desire to eat and also play a part in determining whether the excess calories are used for immediate energy provision or stored as fat in adipose tissues.

Therefore, a good understanding of the interaction between these hormones and how they influence our eating habits is important because the differences in their overall levels in the body and also how the body responds to them appear to play very significant roles in our ability to achieve and maintain a healthy body weight.

Leptin

It is a protein hormone secreted by fat cells (adipose tissues) and which sends signals to the hypothalamus of the brain indicating that the body has ingested enough calories and should stop eating. When leptin is secreted, it makes you feel full and satisfied, speeds up your metabolism, and makes the body to focus on burning stored fat.

Usually, increased levels of leptin in the body let the brain to know that there is enough stored fat and therefore no further need to ingest or store anymore fat. Decrease in leptin secretion can however lead to an individual indulging in overeating as the brain may not be receiving the "full" signal.

Although a lot of people were initially of the view that overweight and obese individuals had genetic problems that made them unable to produce adequate amounts of leptin, scientific studies have however shown that the reverse is actually the case. Several research studies have discovered that overweight and obese individuals instead tend to have higher levels of leptin than slimmer individuals due to the fact that they have become leptin resistant.

Some factors that can be responsible for this include the fact that when people engage in overeating either as a "conditioned response" (a learned habit) or an "emotional eating" problem, the leptin receptors in the hypothalamus over time become "numbed" or "de-sensitized" to the effect of leptin.

Also, it might be possible that the cells transmitting the leptin signals to the hypothalamus are not making it through the blood-brain barrier either due to inflammation of arteries or the low cerebrospinal fluid (CSF) to plasma ratio in overweight and obese individuals. Either or a combination of these factors might cause a vicious cycle of increased weight gain and elevated leptin production which consequently makes the body all the more leptin resistant.

Ghrelin

This peptide hormone was recently discovered to be produced in the gastrointestinal tract and not much is at yet known about its overall function.

Ghrelin secretion by the cells lining the stomach stimulates the appetite. Ghrelin therefore plays an important part in regulating appetite and maintenance of energy balance in the body. The production of ghrelin stops once food enters the stomach as it is known to increase before meals and decrease after meals and thus basically serve to increase appetite to eat.

It becomes pretty obvious that ghrelin is the main culprit sabotaging the weight loss effort of a lot of people especially those using low-calorie diets. Using low-calorie or deprivation based weight loss diet generally results in uncontrollable hunger pangs and eventually leads to overeating.

Furthermore, a research study by University of Bristol scientists found that sleep deprivation may trigger appetite and cravings for sugar-rich, calorie-dense junk food. This according to the research is because sleeping for five hours or less a night causes a 15% reduction in leptin production while interestingly causing a countering 15% increase in ghrelin (the hunger-promoting hormone) production.

Certain lifestyle changes can however help in regulating leptin levels to help in reducing frequent hunger pangs and eliminating cravings for sugary snacks. Some of these changes include avoiding excess sugars and saturated fatty foods; engaging in regular physical exercises; and improving sleeping habits to help increase melatonin production which has been shown to restore normal leptin functions.