The degree of malnutrition is calculated based on a childs body size compared to the median weight for their age. The risk of death increases with increasing degrees of malnutrition.An adaptation of Gomezs original classification is still used today. While it provides a way to compare malnutrition within and between populations, this classification system has been criticized for being "arbitrary" and for not considering overweight as a form of malnutrition. Also, height alone may not be the best indicator of malnutrition; children who are born prematurely may be considered short for their age even if they have good nutrition. Definition by Waterlow
In the 1970s, John Conrad Waterlow established a new classification system for malnutrition. Instead of using just weight for age measurements, Waterlows system combines weight-for-height (indicating acute episodes of malnutrition) with height-for-age to show the stunting that results from chronic malnutrition. One advantage of the Waterlow classification is that weight for height can be calculated even if a childs age is unknown. The World Health Organization frequently uses these classifications of malnutrition, with some modifications. Effects
Malnutrition weakens every part of the immune system. Protein and energy malnutrition increases susceptibility to infection; so do deficiencies of specific micronutrients (including iron, zinc, and vitamins). In communities or areas that lack access to safe drinking water, these additional health risks present a critical problem. Malnutrition plays a major role in the onset of active tuberculosis. It also raises the risk of HIV transmission from mother to child, and increases replication of the virus.
Over 800,000 neonatal deaths have occurred because of deficient growth of the fetus in the mothers womb.Deriving too much of ones diet from a single source, such as eating almost exclusively potato, maize or rice, can cause malnutrition. This may either be from a lack of education about proper nutrition, or from only having access to a single food source.It is not just the total amount of calories that matters but specific nutritional deficiencies such as vitamin A deficiency, iron deficiency or zinc deficiency can also increase risk of death. Overnutrition
Overnutrition caused by overeating is also a form of malnutrition. In the United States, more than half of all adults are now overweight—a condition that, like hunger, increases susceptibility to disease and disability, reduces worker productivity, and lowers life expectancy. Overeating is much more common in the United States, since most people have adequate access to food. Many parts of the world have access to a surplus of non-nutritious food. Increased sedentary lifestyles also contribute to overnutrition. Yale University psychologist Kelly Brownell calls this a "toxic food environment," where fat- and sugar-laden foods have taken precedence over healthy nutritious foods.In these developed countries, overnutrition can be prevented by choosing the right kind of food. More fast food is consumed per capita in the United States than in any other country. This mass consumption of fast food results from its affordability and accessibility. Fast food, which is low in cost and nutrition, is high in calories.