One theory that prompted research on how food intake affects the
average person was the glucostatic theory. Several researchers in the
1940s and 1950s suggested that the brain regulates food intake in order
to maintain a blood-glucose set point. The idea was that people become
hungry when their blood-glucose levels drop significantly below their set
point and that they become satisfied after eating, when their blood-glucose
levels return to that set point. This theory seemed logical because glucose
is the brain’s primary fuel