Starvation is an extreme form of malnutrition. If your body doesn’t get the nutrients it needs, it won’t be able to maintain itself, grow properly and fend off disease. If you don’t eat, your body will deteriorate. First, your mental and physical performance start to suffer. Eventually, your body’s systems begin to shut down to conserve energy.
The extent, type and timeline of damage you experience depends on how much you currently weigh, whether you eat insufficient food or nothing at all, your age, medical condition and many other factors. Generally, during the beginning stages, fatigue, dizziness, dry or scaly skin, and weakness occur, along with intense hunger. Your body is responding to the lack of food, which it needs for energy, by signaling your brain to do something about it.
Starvation causes a decrease in mental function. Like every other part of your body, your brain needs nutrients and energy to function properly. Infants who starve might never develop proper brain function. People over the ages of 2 or 3 might experience temporary poor cognitive function, but recover once they receive nourishment. Your mood likely will change as you become preoccupied by thoughts of food. You also might feel anxious, irritable, angry, withdrawn and depressed.
Your lack of nutrition might lead to gastrointestinal disturbances, feeling cold, hypersensitivity to noise or light, water retention and decreased libido. Your immune system won’t be able to produce sufficient antibodies to fight infection, so you’ll get sick more often. Your gums might swell and bleed. Metabolism decreases as your body tries to conserve as much energy as possible. Weight loss occurs as your body depletes your fat stores, then begins to burn other tissues, such as muscle. These changes are reversible with proper nutrition.
Eventually, your failure to get sufficient nutrients will lead to permanent damage. Teeth decay, and bones weaken due to insufficient calcium. Your hair will fall out. Organs begin to shut down due to the lack of energy and nutrients necessary for maintenance. Heart muscles weaken, and the end result is complete system failure, or death.
Starvation and malnutrition are an epidemic in some underdeveloped countries. Children experience the most damage because they need proper nutrition to develop properly. Even if they survive long periods of starvation, they might experience abnormal growth and other forms of permanent damage. For example, nearly all bone development happens before adulthood, so children who fail to get sufficient calcium in their diets are likely to experience osteoporosis or other bone composition problems later as adults.
People with eating disorders sometimes use starvation techniques to lose weight. For example, people with bulemia force themselves to throw up after meals, which can result in malnutrition and starvation. People with anorexia avoid eating whenever possible. The specific effects of these conditions depend on the severity of the problem, but extreme cases can result in permanent damage -- such as low bone density, tooth decay or gastrointestinal problems -- and death.