The appestat is a hypothetical region of the brain, probably located in the hypothalamus or near the pituitary gland, which helps to regulate appetite. Research on the appestat suggests that if you listen to your body’s feelings of fullness, your body weight will be naturally controlled, since you won’t overeat. Another component of interest is the adipostat, a region of the brain or a series of hormonal outputs that tell people when they are full. In most cases, the adipostat’s function may explain why people who are overweight don’t lose weight, since it may lower the body’s metabolic reaction to smaller amounts of food, causing a person to store weight when calorie intake is lowered.
Together, these two functions, or brain centers, when working properly explain why some people do not lose weight, and why others maintain a stable weight. Yet they can be overridden, especially by people who eat quickly, who have eating disorders, or who use food as a comfort source. Craving for food that is emotional rather than physical may override any messages the appestat sends to the body to convey a feeling of fullness. People who eat too little, as in the case with diseases like anorexia, may be able to successfully ignore feelings of hunger. People who eat too much may also have a appestats that don’t function well and do not successfully communicate feelings of fullness.
Whether the appestat is really a piece of the brain, or describes a series of neurotransmitters and functions that communicate satiety to the body, there are certainly some things we know about hormonal messages sent from the stomach to the brain. For instance, people who discuss the appestat say essentially the same thing as those who just talk about gut to brain messaging. It takes about 20 minutes for the brain to register a feeling of fullness and communicate this so that a person is conscious of feeling full.
People who eat quickly, while reading or watching TV, generally eat too much, since they’re not paying attention to their “fullness” signals. Before long, and well before 20 minutes have passed, they may have eaten much more than the body actually needs. This is why nutritionists and diet experts suggest taking your time while eating, relishing each bite and controlling portions. If you must eat quickly, portion control is vital, since even if you leave the table not feeling completely full, you will likely feel full 20 minutes after your meal is finished. If you begin to feel full before the 20 minutes has passed, you have probably overeaten significantly.
There are many hormone malfunctions that can render the brain appetite control useless. People with low thyroid levels, or excessively high levels can get improper reads from their appestats, making mindful eating a problem. Too little activity can create poor reads from the appestat, or even switch it off. The chemical and neurotransmitter leptin, when in short supply, may create cravings for food. Further, some of the artificial sweeteners on the market, like aspartame, may mistrigger the brain readings of fullness, causing hunger that outstrips nutritional needs. This last has been used as an explanation for why so many people who drink diet sodas develop tummy fat or are overweight.
Some medications and appetite suppressants have been shown to help regulate or turn off the cravings of an appestat out of balance. Fenfluramine or Fen-phen was popular for a time, since it increased serotonin levels, reducing appetite. Unfortunately, fen-phen was linked to dangerous heart arrhythmias and was pulled from the US market in 1997. It did help with weight loss, but did so at a potentially lethal cost to its users. Since then, both pharmaceutical companies and many alternative health companies have come up with a variety of compounds that theoretically control the appestat and adipostat. These include medications that contain leptin, cortisol, and a variety of other hormones or natural compounds. None that are considered safe have as of yet shown significant promise as weight loss agents.