Problems of Excess and Deficit

Classification of body size by use of the Body Mass Index (BMI), a version of weight-for-height (W/H2: weight in kg, height in meters), to assess for overweight and obesity has been in use since it was originally proposed by A. Quetelet in the latter part of the nineteenth century. More recently, it has been extended as a means of classifying undernutrition in adults (FAO 1994; James and Ralph 1994). Full agreement on the exact cut-off points to be used has not

Table IV. C.3.19. A proposed classification using EMI (wt/ht2)

Note: BMI (wt/ht2) is deigned using weight in kilograms and height in meters.

Source: Adapted from USDHHS (1988) and FAO (1994).

Yet been reached, but a provisional classification that ranges from severe undernutrition to severe overnutrition is shown in Table IVC.3.19.

Obesity

That obesity could be a life-threatening condition was recognized by Hippocrates, who observed in one of his aphorisms that “[p]ersons who are naturally very fat are apt to die earlier than those who are slender” (Lusk 1933:8). Because of the significant public health implications of obesity (see Pi-Sunyer 1988 and USDHHS 1988), much research activity has centered on its causation and prevention, but disagreements remain on most major issues. Nevertheless, it is generally agreed that obesity must represent the end result of a cumulative positive error in energy balance and, hence, a failure in whatever mechanism is supposed to maintain the situation. The nature of the mechanism is not agreed upon, although many hypotheses have been advanced. On one extreme is the view presented by L. S. P Davidson and R. Passmore (1969), who wrote that “since the immediate causes of obesity are overeating and under-exercising the remedies are available to all, but many patients require much help in using them” (Garrow 1974: 4). Conversely, the opposite end of the spectrum is typified by E. B. Astwood, who suggested that “obesity is an inherited disorder and due to a genetically determined defect in an enzyme; in other words that people who are fat are born fat and nothing much can be done about it” (Garrow 1974:4).