What Is It Called When You Don't Eat at All?

December 21, 2025 •

3 min read

According to the World Health Organization (WHO), malnutrition is a major contributor to child mortality globally. When people don't eat at all, it can be described by several different terms depending on the context, severity, and intent, including fasting, starvation, and anorexia.

Quick Summary

The specific term for not eating at all depends on the context and duration, ranging from voluntary fasting to involuntary starvation. Medical conditions like anorexia nervosa and ARFID also cause severe food restriction.

Key Points

Anorexia: The medical term for a loss of appetite, which can be a symptom of a wide range of illnesses, not just the eating disorder anorexia nervosa.
Fasting: A voluntary, short-term practice of abstaining from food, often for religious or health-related reasons.
Starvation: An involuntary and prolonged state of severe caloric deficiency that eventually leads to the body breaking down its own tissues for energy.
Anorexia Nervosa: A serious eating disorder where individuals self-starve due to an intense fear of gaining weight and a distorted body image.
ARFID (Avoidant/Restrictive Food Intake Disorder): An eating disorder characterized by limited intake not driven by body image concerns, but rather by factors like sensory aversions or fear of choking.
Physical Effects: Prolonged lack of food leads to severe malnutrition, muscle wasting, and can cause fatal complications like cardiac arrest due to electrolyte imbalances.
Treatment: All severe cases of food restriction require professional medical and, often, psychological intervention to address the underlying cause and safely restore nourishment.

Fasting: A Voluntary Choice

Fasting is the intentional and temporary abstinence from food, and sometimes drink, for a specific period. It is often practiced for religious reasons, weight management, or perceived health benefits. During a fast, the body undergoes a metabolic shift to use stored energy. After the initial few hours of using blood glucose, it starts breaking down stored fat into ketone bodies, entering a state called ketosis.

Common forms of fasting include:

Intermittent fasting: Cycling between periods of eating and fasting, such as the 16:8 method.
Religious fasting: Practices like those in Ramadan or Lent.
Medical fasting: Required before certain surgeries or tests.

Starvation: A Prolonged and Severe Deficiency

Starvation is a state of severe deficiency in caloric energy intake below the level needed to sustain life, and it is the most extreme form of malnutrition. While fasting is controlled and temporary, starvation is a prolonged state of inadequate nourishment. It can be unintentional, caused by famine or medical conditions, or self-inflicted, as in severe eating disorders.

When fat reserves are depleted, the body is forced to break down muscle tissue for energy, a process that can cause severe organ damage and eventually be fatal. The symptoms of starvation are significantly more severe than those of short-term fasting and often require medical intervention to correct.

Anorexia: A Medical Symptom and Condition

The term anorexia, in a medical context, refers to a general loss of appetite or a lack of hunger, and it is a symptom of many underlying issues. This is different from the psychiatric condition anorexia nervosa, though both involve not eating. Causes for a loss of appetite can range from temporary infections to chronic diseases.

Common causes of a loss of appetite (anorexia):

Infections: Illnesses like the flu or pneumonia.
Chronic Diseases: Cancer, kidney failure, or liver disease.
Mental Health Conditions: Depression, anxiety, or high stress.
Medications: Side effects from chemotherapy, antibiotics, or opioids.
Pregnancy: Hormonal changes, especially in the first trimester.

Anorexia Nervosa vs. Starvation

It is vital to distinguish between the clinical symptom of anorexia and the eating disorder anorexia nervosa, which is a severe mental health condition characterized by self-starvation and an intense fear of gaining weight. Anorexia nervosa causes a person to intentionally induce a state of starvation, but the underlying psychological drive is the key differentiator from other forms of starvation. The Minnesota Starvation Study demonstrated that many psychological and social symptoms once attributed specifically to anorexia nervosa are, in fact, direct results of prolonged starvation.

Comparison Table: Fasting vs. Starvation


Feature	Fasting	Starvation
Intent	Voluntary	Involuntary or self-inflicted (eating disorders)
Duration	Typically short-term, with defined start and end points	Prolonged period of inadequate food intake
Bodily Fuel	Uses fat stores (ketosis), spares muscle mass	Exhausts fat, then cannibalizes muscle and organs
Physiological State	Metabolic adaptation to use stored fat efficiently	Metabolic decompensation and organ damage
Health Effects	Can offer some health benefits under supervision	Severe, dangerous, and potentially fatal consequences

The Dangers of Severe Food Restriction

Regardless of the cause, severe food restriction and prolonged starvation are life-threatening and require immediate medical attention. The body's initial metabolic response eventually gives way to critical health issues as essential nutrients are depleted.

Physical effects of prolonged starvation:

Electrolyte Imbalances: Can lead to fatal cardiac arrhythmias.
Malnutrition: Leads to muscle wasting, weakened immune function, and organ damage.
Bone Density Loss: Can be irreversible.
Refeeding Syndrome: A potentially fatal complication that occurs when a malnourished person is fed too rapidly.

Conclusion: Seeking Help is Crucial

Not eating at all is a serious condition with various potential causes and outcomes. While short, controlled fasting may offer benefits, prolonged lack of food leads to starvation, which causes severe and dangerous health complications. In cases of eating disorders like anorexia nervosa, the underlying psychological issues driving self-starvation must be addressed alongside nutritional rehabilitation. Recognizing the signs of an eating disorder or unexplained appetite loss is the first step toward seeking necessary medical and psychological support.

For more information on anorexia nervosa diagnosis and treatment, visit the Mayo Clinic at https://www.mayoclinic.org/diseases-conditions/anorexia-nervosa/diagnosis-treatment/drc-20353597.

Frequently Asked Questions

The medical term for a loss of appetite is 'anorexia.' It is important to distinguish this symptom from the eating disorder anorexia nervosa.

Yes, fasting is typically a voluntary, short-term period without food, while starvation is a prolonged, involuntary, and severe state of inadequate caloric intake. Fasting involves metabolic adaptation, whereas starvation leads to life-threatening damage.

When you don't eat for a prolonged period, your body first uses stored glucose and then fat. If deprivation continues, it will start breaking down muscle tissue for energy, leading to severe malnutrition, organ damage, and electrolyte imbalances that can be fatal.

Yes, mental health conditions such as severe depression and anxiety can lead to a significant loss of appetite (anorexia), causing an individual to stop eating. This often requires both mental health and nutritional intervention.

Initial signs of not eating enough include fatigue, difficulty concentrating, irritability, and nausea, primarily caused by low blood sugar. These symptoms worsen as caloric deficiency becomes more severe.

Refeeding syndrome is a dangerous and potentially fatal complication that can occur when severely malnourished individuals begin eating again. It involves major shifts in fluid and electrolyte balance that can strain the heart and other organs.

Eating disorders often involve specific psychological drivers, such as an intense fear of weight gain, body image distortion, or ritualistic eating behaviors, that are not present in cases of simple appetite loss from other medical issues. A thorough medical and psychological evaluation is needed for a proper diagnosis.