Effects of Learning and Food Form on Intake in Humans

Due to the rising incidence of obesity, much emphasis has been placed on identifying
mechanisms of increased energy intake. At this point, the mechanisms responsible for the
recent increase in obesity prevalence have not been thoroughly examined. Pre-ingestive
influences, such as cognitive factors, may play a larger role in creating an energy surplus
than previously thought. Expectations about the satiating effect of a food may override the
post-ingestive influences in dictating further consumption. In addition, obese individuals
may exhibit a decreased compensatory response to foods as compared to lean individuals.

Understanding the effects of energy content, food form, and learning on satiation, satiety,
and energy intake will allow for a greater understanding of the mechanisms of energy
imbalance as a whole. Food choice is dictated by sensory properties and post-ingestive
effects. By utilizing foods with similar sensory properties, the acquired knowledge derived
from ingesting these foods can be monitored by analyzing subsequent intake at the same meal
and at subsequent eating occurrences. It is hypothesized that the liquid food form will
elicit weaker dietary compensation; that is, energy intake at other eating events will not
be adjusted to compensate for that food. In addition, it is posited that the lower energy
food will cause lower compensation postprandially. By having participants consume the same
test food daily over a two week learning period, it is thought that they will show improved
dietary compensation when the initial testing is repeated due to learned associations
between food properties and metabolism.