
0004 Despite a great deal of individual variability in
the perception of these sensations, hunger can be
associated with clear symptoms; it is partly through
reference to these that people can make judgements
about the intensity of their hunger experience. The
measurement of hunger, desire to eat, or urge to eat is
most commonly conducted using fixed-point or
visual-analog scales. Respectively, these require the
subject to choose a number from a scale or a point
on a line that corresponds to their current state of
hunger. Careful presentation of these scales to people
who understand what is being asked of them will
yield meaningful information. More importantly,
quantifying the subjective experience of hunger
makes it a state, which is amenable to scientific inves-
tigation. Consequently, hunger can be described
qualitatively in terms of the sensations with which it
is associated, and it can also be measured quantita-
tively. This means that the significance of hunger can
be understood through its structure and by its inten-
sity. In recent years, the visual analog scale technique
has been incorporated into the screen of a small hand-
held computer. This device, called the Electronic
Appetite Rating System (EARS) provides a conveni-
ent and user-friendly way of monitoring hunger
during the course of a day.
Hunger, Eating Patterns and the Satiating
Power of Food
0005 If hunger is the feeling that reminds us to seek food,
then the consumption of food is the action that di-
minishes hunger and keeps it suppressed for a certain
period of time, perhaps until the next meal or snack.
The capacity of food to reduce the experience of
hunger is called the satiating power or satiating
efficiency. This power is achieved by certain proper-
ties of the food itself engaging with various physio-
logical and biochemical mechanisms within the body
that are concerned with the processing of food once it
has been ingested. The satiating power of food there-
fore results from a variety of biological processes and
is an important factor in the control of hunger. Some
foods have a greater capacity to maintain suppression
over hunger than other foods. (See Satiety and Appe-
tite: Food, Nutrition, and Appetite.)
0006 How is hunger related to the overall control of
human appetite and food consumption? The feeling
of hunger is an important component in determining
what we eat, how much we eat, and when we eat.
However, it must be seen in a context of social and
physiological variables. On the one hand, eating
patterns are maintained by certain enduring habits,
attitudes, and opinions about the value and suitability
of foods and overall liking for them. These factors,
derived from the cultural ethos, largely determine the
range of foods that will be consumed, and sometimes
the timing of consumption. The intensity of hunger
experienced may also be determined, in part, by the
culturally approved appropriateness of this feeling.
0007On the other hand, normal hunger is more import-
antly associated with the events surrounding meals –
so-called periprandial circumstances – and the
periods between meals. Thus, hunger can be con-
sidered to arise from an interaction between the
physiological requirements of the body for food
(or particular nutrients) and the capacity of food to
satisfy these requirements. Hunger will therefore be
successively stimulated and suppressed, giving rise to
a diurnal rhythm. This rhythm, and the relationship
between hunger and eating, may be modulated by
certain social factors (e.g., distressing psychological
events) or interrupted by some disease states.
Hunger and the Satiety Cascade
0008When food consumption reduces hunger and inhibits
further eating, two processes are involved. For tech-
nical precision and conceptual clarity, it is useful to
describe the distinction between satiation and satiety.
Both terms may be assigned workable operational
definitions (i.e., definitions that depend upon meas-
urable events). Satiation can be regarded as the pro-
cess that develops during the course of eating and
eventually brings a period of eating to an end.
Accordingly, satiation can be defined by the measured
size of the eating episode (volume or weight of food,
or value of the energy content). Hunger declines as
satiation develops and usually reaches its lowest point
at the end of a meal. Satiety is defined as the state of
inhibition over further eating that follows the end
of an eating episode and arises from the consequences
of food ingestion. The intensity of satiety can be
measured by the duration of time elapsing until eating
is recommenced, or by the amount consumed at the
next meal. The strength of satiety is also measured by
the duration of the suppression of hunger. As satiety
weakens, so hunger is restored. Figure 1 indicates the
changes that occur in the rating of hunger during a
meal (as satiation develops) and following a meal (as
satiety evolves). It can be seen that the measurement
of hunger is an important index of the degree of
satiation and satiety.
0009In the view of some researchers, satiation and
satiety can be referred to as intrameal satiety and
intermeal satiety, respectively. What mechanisms are
responsible for these processes? It is clear that the
mechanisms involved in reducing hunger and in
maintaining the suppression over hunger range from
those that occur when food is initially sensed, to the
HUNGER 3179