Because of the current obesity epidemic and its considerable effect on health, lifestyle,
and longevity, there is a pressing need to further understand the neural pathways involved in the
control of body weight, and the motivational states underlying ingestive behaviors. In a number of
obese individuals, the homeostatic mechanisms that regulate energy consumption are overpowered
by environmental influences, such as an abundance of highly palatable foods which are difficult to
resist, and which can lead to their consumption beyond caloric need [1]. A strong liking for highly
palatable foods has been linked to increased consumption [2, 3] and research has established that
obese people show a greater liking and selection of sweet and fatty foods than their leaner
counterparts [4-6]. Opioid peptides and opiate receptors are believed to mediate the affective
response to highly palatable food [7-10]. Evidence suggests that the opioid system modulates one’s
perception of the hedonic properties of food and, consequently, food consumption [10, 11].
Therefore, the endogenous opioid system is likely to play an important role in food preferences and
risk for obesity. Research suggests that targeting the opioid system may be an effective treatment
option for certain individuals suffering from obesity. The following chapter will review the
literature on the role of the opioid system in food consumption and examine the possibility that
certain drugs, which target this system, are beneficial for weight loss and the treatment of obesity.
Keywords: Obesity, endogenous opioids, opioid antagonists, palatability, food intake.
