Starvation

Starvation is a condition resulting from a severe and prolonged deficit of caloric intake, in which the body's energy needs are not met. It leads to mobilization of stored fats and, later, body proteins to sustain essential functions, with loss of body mass and multiple physiological changes.

Causes of starvation include famine and food insecurity during disasters, chronic poverty, displacement, or illnesses that impair intake or increase energy requirements. Prolonged voluntary fasting or extreme dieting can approach starvation in some contexts, but clinically significant starvation typically involves a sustained energy deficit beyond ordinary fasting.

Physiological changes: after a short period of food deprivation glycogen stores are depleted within about 24–48 hours. The body shifts to increased lipolysis and ketogenesis to supply energy, while protein breakdown provides glucose for the brain and other tissues. Hormonal changes (low insulin, high glucagon and cortisol) slow metabolism, conserve energy, and eventually reduce organ function. Electrolyte disturbances and immune impairment can occur; prolonged starvation may cause cardiac and renal dysfunction.

Clinical features and complications: rapid weight loss, weakness, fatigue, cold intolerance, hair and skin changes, bradycardia, hypotension. In children, growth delay and developmental impairment may occur. Refeeding after starvation carries risk of refeeding syndrome—electrolyte shifts that can be life-threatening without careful management of fluids and minerals.

Treatment and prognosis: management focuses on restoring energy and nutrient intake gradually, correcting electrolyte and vitamin deficiencies (notably thiamine), and treating infections or comorbid conditions. In humanitarian contexts, food security and nutrition support are essential. With timely, careful refeeding, many effects are reversible; prolonged starvation can cause lasting damage or death.