Gastroenteric hormone responses to hedonic eating in healthy humans

Hedonic eating differentiates from homeostatic eating on two main aspects: the first one is that eating occurs when there is no need for calorie ingestion and the second one is that the food is consumed exclusively for its gustatory and rewarding properties. Gastroeneteric hormones such as ghrelin, colecystokinin-33 (CCK) and peptide YY3-36 (PYY3-36) are known to play a pivotal role in the homeostatic control of food intake. To the contrary, their role in hedonic eating has been never investigated. Here we report peripheral responses of CCK, PYY3-36 and ghrelin to the consumption of food for pleasure in well-nourished satiated healthy subjects. Plasma levels of CCK, PYY3-36 and ghrelin were measured in 7 satiated healthy subjects before and after ad libitum consumption of both a highly pleasurable food (hedonic eating) and an isoenergetic non-pleasurable food (non-hedonic eating). The consumption of food for pleasure was associated to a significantly increased production of the hunger hormone ghrelin and a significantly decreased secretion of the satiety hormone CCK. No significant changes in plasma PYY3-36 levels occurred in the two eating conditions. These preliminary data demonstrate that in hedonic eating the peripheral hunger signal represented by ghrelin secretion is enhanced while the satiety signal of CCK production is decreased. This could be responsible for the persistence of peripheral cues allowing a continued eating as well as for the activation of endogenous reward mechanisms, which can drive food consumption in spite of no energy need, only for reward.