A Psychobiological System Approach
to Appetite and Weight Control
JOHN E. BLUNDELL
Appetite control implies a control over energy intake. Some researchers argue that habitual addition of only 20–30 kcal per day over a number of years will lead to significant body weight increases. If human beings are the most intelligent life force on this planet, why can they not adjust their eating by the very small amounts required for weight stability? Some explanation for this may be found in an examination of the processes involved in the regulation of appetite.
The power of a systems approach is that it allows the simultaneous evaluation of a number of factors that influence the expression of appetite and the control of body weight. It permits an assessment of the relative strength of each factor rather than concentrating only on one domain. Research is certainly needed on specific mechanisms that control particular aspects of our physiology, biochemistry, nutrition, and behavior related to eating and weight control. Also required is a conceptualization of how these mechanisms act cohesively to influence the physiology, conscious sensations, and actions of people functioning as individuals. This can be provided by the psychobiological system.
The essence of this view is the intention to understand the control of appetite and body weight (and disorders of these phenomena) as the products of a network of interactions among elements forming part of a psychobiological system. A simplified model of the system is set out in Figure 8.1.
A consideration of anthropological, epidemiological, and experimental evidence suggests that it is easier for human beings to gain weight than to reduce weight. This implies that the control of appetite (by the psychobiological system) is asymmetrical. Figure 8.2 illustrates a simple conceptualization of how this arises. The extension of Claude Ber-