The prevalence of obesity has provided a strong incentive to understand the motivation to consume high-fat foods. Taste palatability of high-fat food is cited as the primary influence in the over consumption of dietary fat (Drewnowski, 1997; Drewnowski and Greenwood, 1983; McCrory et al., 1999, 2000; Warwick and Schiffman, 1990) and there is a strong positive correlation between obesity and daily high-level intake of dietary fat (McCrory et al., 1999; Miller et al., 1990, 1994). Traditionally, the sensory perception of dietary fat during ingestion has been characterized in terms of textural and postingestive effects. Certainly, dietary fat contributes to the mouthfeel of food-stuffs and can act as a positive reinforcer through fatty acid receptors found in the digestive tract that stimulate pathways leading to the natural reward centers of the brain. However, across the last decade, accumulating evidence from both molecular and behavioral research has begun to challenge the traditional perspectives on dietary fat perception by introducing the concept of chemoreception of dietary fat within the oral cavity, specifically through the gustatory system, as providing immediate and selective signals during dietary fat consumption. Like humans, rodents demonstrate a robust preference for high-fat foods (Greenberg and Smith, 1996; Smith et al., 2000; Warwick and Synowski, 1999; Warwick et al., 1990) and represent the most typical animal model in which the reception, transduction, and neural signaling of the peripheral gustatory system has been explored. This chapter reviews the behavioral evidence supporting a role of the gustatory system in the chemoreception of fatty acids, the principle chemical component of dietary fat.
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