Appetite Control – Factors that Stimulate and Suppress Hunger

Food intake is controlled by multiple areas of the brain, particularly in the hypothalamus. The two most important centers are the the hunger center and the satiety center. While hunger is the need to eat, appetite is usually defined by the desire to eat, especially certain foods or large quantities of food that extends beyond what is necessary. When the hunger center is stimulated, it will drive a person to seek and consume food. once the satiety center is stimulated, it will then inhibit the hunger center. This stops a person from eating.

Control of Appetite by Feeding Centers in the Brain

The hunger center is also known as the lateral nuclei because of its location in the hypothalamus, while the satiety center is known as the venteromedial nuceli.

Regulation of food intake is not isolated to just these areas. There are three other areas in the brain that influence feeding and this includes :

• Paraventricular nuclei
• Dorsomedial nuclei
• Arcuate nuclei

These feeding centers do not just drive a person to eat or stop eating. It also influences blood sugar levels, energy storage in fat cells and energy utilization in terms of the body’s metabolism.

The feeding centers can be affected by :

• nerve signals through the vagus nerve as the stomach fills (distends) or when it is empty – refer to Hunger Pangs
• chemicals released from the stomach (ghrelin) and small intestine (CCK) – refer to Digestive Hormones
• chemicals in the blood particularly from food breakdown like glucose (carbohydrate), amino acids (protein) and fatty acids (fats)
• chemicals from the fat cells (leptin)
• cerebral nerve signals as a result of sight, smell and taste

The arcuate nuclei plays an important role in the coordination of all these signals (chemical and nerve) and influencing appetite by the different types of neurotransmitters that it produces :

• orexigenic neurotransmitters that increase feeding
• anorexigenic neurotransmitters that decrease feeding

Any substance that increases appetite, even chemicals not produced by the arcuate nuclei, are referred to as orexigenic substances, like cortisol produced by the adrenal gland. Similarly, any substance that decreases appetite is known as anorexigenic substances, like insulin produced by the pancreas.

However, these substances do not just increase or decrease appetite, they also influence energy expenditure – the body’s metabolism. Many weight loss drugs act as anorexigenic substances by decreasing appetite and increasing energy expenditure.

Related Articles

1. Medical Weight Loss
2. What are Hunger Pangs?

Article reviewed by Dr. Greg. Last updated on August 2, 2010