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Cravings
Most people have definite food preferences and dislikes. Ronald Reagan's fondness for jellybeans and George Bush's dislike of broccoli are two highly publicized examples. Such preferences or dislikes seldom interfere with nutritional status, and are not a cause for concern.
Some people, however, are beset with abnormal or bizarre cravings. The mechanisms of abnormal cravings are poorly understood. Researchers know that centers in the hypothalamus portion of the brain control appetite and satiety, but the sources of abnormal cravings are unknown. There are, however, a number of conditions that appear to promote unusual cravings.
Causes of cravings
Bulimia
The term bulimia comes from the Greek word for ravenous hunger. Bulimia is a common eating disorder characterized by periodic food binges, usually followed by self-induced vomiting or some other means of avoiding weight gain from overeating. The disorder strikes mostly young women who are often high achievers. Sometimes it occurs along with anorexia nervosa, a serious disease marked by self-starvation. A person with bulimia consumes huge amounts of food, usually sweets or "junk food," and then, often with guilt feelings, tries to rid herself of the food by vomiting or laxative abuse. The causes of bulimia are poorly understood, but are believed to involve a combination of psychological and hormonal factors.
Medications
Many drugs alter appetite. Although loss of appetite is one of the most common adverse drug reactions, some medications have an opposite effect, increasing appetite and cravings for certain foods. Steroid medications are among the most common. People on long term steroid therapy often complain of increased hunger, and weight gain is a common consequence. Other hormonal agents, such as oral contraceptives or estrogen replacement therapy, may also produce food cravings or increased appetite.
Nutritional deficiencies
Certain nutritional deficiencies produce abnormal food cravings. Contrary to popular belief, the cravings usually are not for foods that would correct the deficiencies. For example, people with iron-deficiency anemia often have unusual appetites, craving substances such as ice, clay, dirt, or starch, rather than iron-rich foods such as liver. Less commonly, zinc or copper deficiencies may also produce unusual cravings.
Obesity
Obesity is a complex, poorly understood disorder that is thought to involve genetic factors as well as faulty appetite controls. Obese people often complain of feeling hungry, even after eating a large meal. It is thought that their excess fat cells may somehow send signals to the appetite control center in the brain, resulting in excessive hunger.
Pica
Pica is characterized by cravings for substances that are not ordinarily considered food. It occurs most commonly in children, who may crave such diverse substances as paint chips, dirt, and even feces. Such cravings usually are linked with emotional problems or mental retardation, although nutritional deficiencies may also play a role. Pica in adults is usually due to emotional problems, but in some instances, it may be due to cultural practices. For example, eating soil during pregnancy is common among certain African cultures, and is still practiced by some African-Americans.
PMS
Premenstrual syndrome is a constellation of symptoms that occurs in the week or so before a woman's menstrual period. Many of the symptoms, such as irritability, nervousness, or depression, are emotional; others, such as breast tenderness or abdominal and leg swelling, are physical. Some, such as a craving for sweet or sour foods, may be a combination of the two.
Pregnancy
There are many jokes about food cravings during pregnancy, but to the pregnant woman who wakens in the middle of the night craving a sour pickle or ice cream, they may not be so funny. Some of these cravings, particularly for salty foods, have a physiological basis. During pregnancy, a woman's blood volume doubles, and extra sodium is needed to maintain the body's proper fluid balance. Some food cravings are related to folklore. For example, eating soil or clay during pregnancy stems from the folk belief that these substances ease labor. In reality, eating these substances can cause anemia.
Sugar and sweets
Most people have a definite preference for foods that taste sweet, and many crave them. Studies show that babies are born with a "sweet tooth." When newborn infants are offered liquids of varying sweetness, they suck most eagerly on the sweetest solutions. There are two major theories to explain our preference for sweets. One is that sugar is rapidly converted to glucose, the body's major fuel. The second involves our evolution — plant foods that taste sweet are less likely to be poisonous than those that taste bitter or sour. Thus, our prehistoric ancestors may have turned to sweet-tasting foods because, through trial and error, they learned that they were safe to eat.
Advice about cravings
- Most food cravings are
harmless if kept under
control. The exception is a
craving for substances that
are not foods, such as
chalk, ice, or paint chips.
Such cravings can result in
nutritional deficiencies or poisoning.
- Some unusual cravings
may be a sign of an underlying medical problem,
such as anemia or a hormonal disorder
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