Hunger, Eating, and Obesity

HUNGER, EATING, AND OBESITY

It is often said that the surest path to the heart is via the stomach, and for many peo-ple, eating is indeed one of the great pleasures in life (Figure 12.5). This pairing of food and pleasure is no accident—the survival of every animal requires an adequate supply of energy and nutrients. These are provided via the process of digestion, through which nutrients from food are converted into energy that supplies body heat, enables the mus-cles to contract, and supports all our other life functions. An organism insensitive to these needs would have a short life span, and so it is no surprise that all animals have sophisticated internal mechanisms to monitor the availability of various nutrients within the body. Of course, when the need arises, these mechanisms can cause the ani-mal to seek food.

How does the organism manage this feat of self-regulation? Is there an “appestat” that controls appetite and the behaviors that govern the intake of nutrients, the same way a thermostat controls the body’s temperature? The answer turns out to be yes, but only within the context of a complicated, multipart control system. To understand this control system, we must consider its physiological, cultural, and cognitive aspects.