Decreased appetite is generally caused by psychological factors, such as stress or depression. When stressed, the body gives signals as if it is in danger. The brain then releases the hormone adrenaline which makes the heart beat faster and digestion slows down. This is what reduces appetite.

However, decreased appetite was not only motivated by psychological factors. Decreased appetite accompanied by other symptoms could be a sign that the body is stricken with disease. The following is a list of diseases that are often associated with reduced appetite:

 Patients with acute or chronic kidney failure can experience impaired filtering of toxic substances in the body, reduced red blood cell production, electrolyte disturbances, and high blood pressure. Patients with kidney failure often lose their appetite or find the taste of the food they eat is different.

In addition, one of the causes of decreased appetite in patients with kidney failure is nausea. Nausea appears due to the buildup of toxins in the blood (uremia), because the kidneys are no longer able to work properly.

Thyroid disorders, such as hypothyroidism, can also cause decreased appetite. This is thought to be because thyroid disorders can affect the taste sensation on the tongue when eating, as well as interfere with the work of the brain that regulates appetite.

Decreased appetite in AIDS sufferers occurs because they are susceptible to infections, including infections of the gastrointestinal tract. This condition is characterized by symptoms of nausea, vomiting, and diarrhea. As the disease progresses, people with AIDS can also experience a yeast infection or thrush in the mouth that interferes with the eating process.

According to one study, decreased appetite in HIV/AIDS sufferers is also associated with hormonal disorders, chronic inflammation in the body due to infection, side effects of HIV treatment, and brain disorders that lead to dementia.

Many people with cancer experience decreased appetite. The cause can be cancer itself, it can also be a side effect of cancer treatment that can affect the sense of taste and desire to eat.

In addition, cancer patients also often experience digestive problems, such as nausea, vomiting, flatulence, and diarrhea. This condition also causes reduced appetite in people with cancer.

Heart failure is a condition in which the heart is unable to pump blood to meet the needs of the body's organs optimally. The sufferer will experience shortness of breath and swelling in the legs and feet due to fluid buildup. If this fluid buildup occurs in the digestive tract, the patient will feel bloated and nauseous, resulting in a reduced appetite.

Certain medications have side effects of nausea and drowsiness. These side effects can reduce appetite. Drugs known to cause this side effect include antibiotics, blood pressure lowering drugs, sleeping pills, cough drops, codeine, diuretics, and anabolic steroids.

Leptin is a hormone whose function is to regulate appetite. In one study, it was found that leptin levels in patients with tuberculosis (TB) decreased due to prolonged inflammation. This condition causes the appetite of TB sufferers to decrease and their weight to fall.

Immediately consult a doctor if your appetite decreases for no apparent reason, so that the doctor can find out the cause and provide the right treatment. What's more, if you lose weight drastically even though you are not on a diet.