DIETARY INSUFFICIENCY sufficient energy, in the form of carbohydrates, fats, and proteins, for the body's daily metabolic needs amino acids and fatty acids to be used as building blocks for synthesis of structural and functional proteins and lipids vitamins and minerals, which function as coenzymes or hormones in vital metabolic pathways or, as in the case of calcium and phosphate, as important structural components.

several conditions lead to dietary insufficiencies. Poverty Infections Acute and chronic illnesses Chronic alcoholism Ignorance and failure of diet supplementation Self-imposed dietary restriction. Anorexia nervosa, bulimia, and less overt eating disorders affect many individuals who are concerned about body image and are obsessed with body weight Other causes. Additional causes of malnutrition include gastrointestinal diseases and malabsorption syndromes, genetic diseases, specific drug therapies

PROTEIN-ENERGY MALNUTRITION (PEM) Severe PEM is a serious, often lethal disease affecting children. It is common in low-income countries, where up to 25% of children may be affected, and where it is a major factor in the high death rates among children younger than 5 years. In the West Africa country of Niger, which suffered a severe famine in 2005, United Nations reports estimate that there were, respectively, 150,000 and 650,000 children with severe and moderate malnutrition. In that country, malnutrition was a direct or indirect cause of mortality in 60% of children under age 5. Decreased food intake can also occur due to sharp increases in prices, as was seen in the first half of In developed countries, PEM occurs in elderly and debilitated patients in nursing homes and hospitals.

Marasmus A child is considered to have marasmus when weight falls to 60% of normal for sex, height, and age. A marasmic child suffers growth retardation and loss of muscle, the latter resulting from catabolism and depletion of the somatic protein compartment. This seems to be an adaptive response that provides the body with amino acids as a source of energy. The visceral protein compartment, which is presumably more precious and critical for survival, is only marginally depleted, and hence serum albumin levels are either normal or only slightly reduced.

Kwashiorkor Kwashiorkor occurs when protein deprivation is relatively greater than the reduction in total calories This is the most common form of PEM seen in African children who have been weaned too early an subsequently fed, almost exclusively, a carbohydrate diet (the name kwashiorkor is from the Ga language in Ghana describing a disease of a baby due to the arrival of another child). The prevalence of kwashiorkor is also high in impoverished countries of Southeast Asia

ANOREXIA NERVOSA AND BULIMIA Anorexia nervosa is self-induced starvation, resulting in marked weight loss; bulimia is a condition in which the patient binges on food and then induces vomiting. Anorexia nervosa has the highest death rate of any psychiatric disorder. Bulimia is more common than anorexia nervosa, and generally has a better prognosis; it is estimated to occur in 1% to 2% of women and 0.1% of men, with an average onset at 20 years of age. These eating disorders occur primarily in previously healthy young women who have developed an obsession with body image and thinness. The neurobiologic underpinnings of these diseases are unknown, but it has been suggested that altered serotonin metabolism may be an important component.

Bulimia In bulimia, binge eating is the norm. Large amounts of food, principally carbohydrates, are ingested, only to be followed by induced vomiting. Although menstrual irregularities are common, amenorrhea occurs in less than 50% of bulimic patients, probably because weight and gonadotropin levels are maintained near normal. The major medical complications relate to continual induced vomiting, and the chronic use of laxatives and diuretics. They include (1) electrolyte imbalances (hypokalemia), which predispose the patient to cardiac arrhythmias; (2) pulmonary aspiration of gastric contents; and (3) esophageal and gastric cardiac rupture. Nevertheless, there are no signs and symptoms that are specific for bulimia; the diagnosis must rely on a comprehensive psychologic assessment of the person. A recent trend in bulimic patients has been the combination of binge eating with high ingestion of alcohol. Needless to say, the combined effects of bulimia and alcoholism are devastating.

Obesity Excess adiposity (known as obesity) and excess body weight are associated with the increased incidence of several of the most important diseases of humans, including type 2 diabetes, dyslipidemias cardiovascular disease, hypertension, and cancer. Obesity is defined as an accumulation of adipose tissue that is of sufficient magnitude to impair health. As with weight loss, excess weight is best assessed by the body mass index or BMI.

The normal BMI range is 18.5 to 25 kg/m2, although the range may differ for different countries. Individuals with BMI above 30 kg/m2 are classified as obese; those with BMI between 25 kg/m2 and 30 kg/m2 are considered to be overweight. For the sake of simplicity, unless otherwise noted, the term obesity will be applied to both the truly obese and the overweight.