The feeling of hunger represents a physiological state that is controlled by a variety of factors: hormones, nutrient levels in the blood, neural signals from the gastrointestinal tract, and psychological factors. A certain region of the hypothalamus, known as the hunger center, elicits feelings of hunger when stimulated by low blood glucose levels. The signals from the brain may also cause hunger pangs or churning of the stomach.
Even when blood glucose levels are normal, stimuli such as smell, sight, taste, and thoughts of food may stimulate the hunger center. Emotional states, such as stress, may also affect the hunger center. Once hunger is satisfied through intake of sufficient food, a feeling of satiety prevails. Feelings of satiety prevent further intake of food. Thus, the feelings of hunger and satiety are mechanisms to regulate intake of food into the body.
Why would hunger be constant?
Under some conditions, one may feel a constant hunger for food. This is often, but not always, a symptom of an underlying disease. A constant feeling of hunger may also be accompanied by other symptoms. One may even confuse feelings of low energy and stomach pain with feelings of hunger. Left untreated, constant hunger can lead to excessive eating and weight gain.
Constantly feeling hungry does not always indicate an underlying pathology. Constant hunger sensations may sometimes occur even during normal physiological states. Pregnancy is one example of a normal physiological state that is characterized by constant feelings of hunger. However, these feelings are short-lived. A constant hunger sensation can be a cause for concern when accompanied by other symptoms, such as weight gain or weight loss. Medical attention must be sought in such cases.
Excessive Eating vs Excessive Hunger
Although hunger sensations normally drive our eating habits, hunger and eating are not always linked. People may overeat even when they do not feel hungry. Alternatively, a hungry individual may not be able to tolerate a large quantity of food. Sometimes, one may not even be able to take small meals despite feeling hungry. Therefore, a distinction must be made between sensations of excessive hunger and the act of excessive eating. Excessive hunger refers to feelings that either return a short while after eating a meal, or feelings that do not subside even after eating.
Read more on hungry after eating.
Causes of Excessive Hunger
As mentioned previously, a variety of physiological, pathological, and psychological states can elicit constant hunger sensations. In some cases, a feeling of constant hunger may be the only symptom. In other cases, constant hunger sensations may be accompanied by other signs and symptoms. The following are some of the common conditions that may elicit feelings of constant hunger.
- Diabetes mellitus: Diabetes mellitus is a common condition in many developed countries. It is also one of the leading causes of constant hunger. Diabetes is classified into two major types: type I and type II diabetes. In type I diabetes, there is insufficient production of insulin hormone by the pancreas. In type II diabetes, the cells of the body become unresponsive to the insulin hormone. Insulin is required by most cells of the body to take up glucose from the blood stream. In diabetes, the dysfunction of the insulin pathway results in many cells not being able to utilize the glucose in the blood, resulting in cellular starvation and a rise in blood glucose levels.
- Hypoglycemia: Excessively low levels of blood glucose (termed hypoglycemia) also cause stimulation of the hunger center. This results in constant feelings of hunger. One of the common causes of hypoglycemia is poorly managed diabetes.
- Pregnancy: Pregnancy is a normal physiological state that causes excessive feelings of hunger in women. This hunger is the result of an increased demand for nutrients required for the growth of the fetus. In addition to constant hunger, pregnant women frequently have cravings for certain types of foods. These cravings are usually short-term in nature.
- Stomach problems: Changes in appetite may also result from problems in the stomach and the upper intestine. Peptic ulcer disease and gastritis commonly produces a dull or burning abdominal pain that eases upon intake of food. This may lead one to erroneously believe that the pain in the abdomen caused by these conditions is a signal for feeding.
- Intestinal worms: Constant hunger, especially in children, is often attributed to an infestation of the intestine with worms. However, this is true only in a few cases.
- Thyroid dysfunction: One of the determinants of hunger and food intake is a person’s metabolic activity. People with higher metabolic activity feel more hungry, and take in more food, than people with slower metabolism. Thyroid hormones play a key role in regulating the metabolic activity in the body. In hyperthyroidism, an overactive thyroid gland may lead to feelings of constant hunger.
- Stress: Some of the causes of constant hunger are psychological in nature. Stress is one of the common psychological factors that can influence feelings of hunger and food intake. The hormones released during stress can disrupt blood glucose level. A stressed person may, therefore, feel excessive hunger and may eat just for the comfort it provides. Alternatively, stress may also lead to diminished appetite.
- Eating disorders: Constant feelings of hunger may also occur in certain eating disorders such as bulimia. These eating disorders are actually mental health issues that influence eating patterns. In bulimia, a person may go on binge eating. This overeating is usually followed by guilt that may lead a person to purge by inducing vomiting.
- Mental health conditions: Apart from eating disorders, other mental health conditions may also influence feelings of hunger in a person. An increase in appetite may occur when a person feels anxious or depressed. Food in these circumstances provides psychological comfort. However, seeking comfort in eating can easily lead to overeating and obesity.
- Medications: Constant feelings of hunger and increased appetite may also result from intake of certain drugs. Examples of such drugs include antidepressants, anti-anxiety drugs, corticosteroids, and antipsychotics. Some drugs, such as antibiotics and non-steroidal anti-inflammatory drugs, may also aggravate peptic ulcers and gastritis. The resulting abdominal pain may be mistaken for hunger pangs.
- Other causes: Alcohol and illicit drugs may also cause increased feelings of hunger. Alcohol worsens symptoms of peptic ulcer disease and gastritis. Marijuana is known to increase appetite.