Modulation of Sleep by Obesity, Diabetes,
Age, and Diet

Diet, or the consumption of calories from the external envi-
ronment, is an obligatory task of all metazoans. Yet the

effects of the nutritional environment are not simply a binary
fed/not-fed switch. The type and density of a nutrient source
can have profound secondary effects. In a medical sense, the
dietary components can be considered good or bad, either
preventing or enhancing the onset of disease due to both
caloric load and the presence of auxiliary chemicals that can
be beneficial or toxic to cells and organ systems. However,
from a broader perspective, the dietary composition can also

provide essential information about the state of other attri-
butes of the environment. These factors may have shaped the

life history characteristics and behavioral responses of all
organisms. For instance, the ripeness (amount of sugar) in
fruits can provide seasonality information. The availability
of food may also, directly or indirectly,