Being hungry is natural and can be due to increased physical activity or pregnancy. However, an increased appetite over a long period of time could be a result of mental health disorders or diseases:
- Stress and Anxiety
- Premenstrual syndrome
- Graves’ disease
- Social factors
I. Hunger and Mental Disorders
1- Hunger, Stress, and Anxiety
The link between appetite, stress, and anxiety is associated with the “Fight-or-Flight” mechanism that involves hormonal communications between parts of the brain, including the hypothalamus and the pituitary gland, and the adrenal glands found on top of the kidneys.
Generally, in temporary stressful situations, the hypothalamus secretes CRH (corticotropin-releasing hormone) to stimulate the secretion of ACTH (Adrenocorticotropic hormone) by the pituitary gland leading to the secretion of the hormone noradrenaline (norepinephrine) by the adrenal glands which suppress appetite .
In the event of prolonged stress and anxiety, the hypothalamus secretes CRH to stimulate the secretion of ACTH by the pituitary gland leading to the secretion of a glucocorticoid known as cortisol by the adrenal glands that increase appetite, and therefore, hunger .
2- Hunger and Depression
In case of increased appetite, there is a hyperactivation of the nervous system reward circuitry which contains pleasure centers. This circuitry includes a pathway known as the dopamine reward pathway (mesolimbic pathway) responsible for the release of dopamine that promotes motivation and desire for reward stimulus such as an increase in appetite.
3- Hunger and Bulimia nervosa
Bulimia or bulimia nervosa is an eating disorder characterized by excessive eating followed by purging (vomiting) due to feelings of shame or guilt, associated with a potential weight gain. Bulimia is often associated with anxiety and depression.
Binge eating, purging, and the feeling of hunger appear to be associated with hedonic processes that involve motivation for pleasure, such as binge eating, and avoidance of pain such as potential weight gain. Therefore, purging is associated with preventing potential weight gain resulting in a vicious circle of binge eating, purging, and hunger .
II. Hunger and Pregnancy
During pregnancy, feeling hungry is natural and common, particularly during the second semester due to cravings, morning sickness, and the necessity to feed the growing baby. For this, a pregnant woman requires an additional supply of energy that triggers hunger and the need to consume more food.
II. Hunger and Premenstrual Syndrome
Physical and emotional changes take place before the start of the menstrual period and are known as premenstrual syndrome (PMS). During this period symptoms, such as stress, anxiety, sleeping difficulty, headache, mood swings, and increased hormonal levels, are common.
The level of hormones such as estrogens, serotonin, and cortisol are significantly increased resulting in metabolic surges and enhanced appetite.
III. Hunger and Chronic Diseases
1- Hunger and Diabetes
During diabetes, there is an increase in glucose levels in the blood known as hyperglycemia. However, the glucose is not being delivered to the cells to produce the energy necessary for their function.
Insulin resistance or lack of it results in a reduction of glucose absorption by the cells resulting in excessive hunger known as polyphagia.
2- Hunger and Hyperthyroidism
Hyperthyroidism is a disorder characterized by increased production by the thyroid of the thyroid hormones thyroxine (T4), and triiodothyronine (T3) that leads to an increase of the body metabolism and energy production.
This excessive metabolic demand is associated with increased glucose consumption by the cells which lowers the level of glucose in the blood causing hunger.
3- Hunger and Graves’ Disease
Graves’ disease is an autoimmune disease that affects the thyroid and causes hyperthyroidism. The increased metabolic demand for glucose and energy production results in hunger attacks.
4- Hunger and Hypoglycemia
Hypoglycemia is associated with a reduction in glucose level in the blood reaching a level of under 4 mmol/L due to several causes such as diabetic treatment using insulin and sulfonylureas, tumors, infections, organ failure, autoimmune diseases, and endocrine diseases . This reduction reduces the level of glucose available for the cells’ function which triggers hunger.
For instance, insulinoma, a small tumor of the pancreas, results in increased secretion of insulin which increases glucose intake by the body cells.
IV. Hunger and Medication
Appetite suppressants or diet pills are used to help individuals lose weight by reducing the brain urge to consume food. Withdrawing from using these medications can trigger hunger and the need to consume more food and energy.
As mentioned above, diabetic medications, such as insulin and sulfonylureas, also reduce the level of glucose in the blood which triggers the need for more energy, and therefore, hunger.
V. Hunger and Social Factors
Several societal factors can promote hunger and weight loss over a healthier diet that provides quality nutrients to our bodies. For instance, the need to lose weight in a short period of time can be dictated by certain cultures that are concerned with body aesthetics.
Another factor is associated with a type of food. A diet rich in carbohydrates increases appetite due to the fast release of glucose in the blood and its rapid use by the cells of the body which results in increased appetite and hunger.
In general, feeling hungry is normal and common in healthy individuals due to physical and mental activities. However, hunger can also be due to more mental disorders and chronic diseases that require treatment. In the case of mental disorders such as anxiety and depression, antidepressants, anxiolytics, and cognitive-behavioral therapies are required to reduce appetite and prevent weight.
For hunger related to chronic diseases, such as diabetes, hyperthyroidism, and Graves’ disease, a follow-up by professionals is essential to monitor both treatment and excessive hunger known to be associated with these diseases.