The researchers, led by Palmiero Monteleone of the University of Naples SUN in Italy, suggested that so-called ‘hedonic’ hunger – triggered by a desire for pleasure, rather than hunger – may lead the body to release certain substances, such as the hormone ghrelin, which stimulates hunger, and 2-arachidonoylglycerol (2-AG), which may drive further consumption even when satiety has been reached. This could help explain the rapid increase in obesity rates, as tasty food has become more readily accessible to many.
"'Hedonic hunger' refers to the desire to eat for pleasure, and to enjoy the taste, rather than to restore the body's energy needs," said Monteleone. "For example, desiring and eating a piece of cake even after a satiating meal is consumption driven by pleasure and not by energy deprivation. The physiological process underlying hedonic eating is not fully understood, but it is likely that endogenous substances regulating reward mechanisms like the hormone ghrelin and chemical compounds such as 2-arachidonoylglycerol (2-AG) are involved."
The pilot study involved eight participants, who ate either highly palatable foods (traditional Italian cakes) or macronutrient-matched less palatable foods (bread, butter and milk). The researchers then periodically tested blood levels of ghrelin and 2-AG, and found that these increased with hedonic eating, but not with non-hedonic eating.
The authors wrote that the idea of eating for pleasure alone, rather than homeostatic eating – eating for survival – is relatively new, but it is intuitive that the desire for pleasurable food “may powerfully stimulate food intake in an environment where highly palatable foods are omnipresent, and contribute to the diffusion of overweight and obesity.”
Monteleone added: “Understanding the physiological mechanisms underlying this eating behavior may shed some light on the obesity epidemic. Further research should confirm and extend our results to patients with obesity or with other eating disorders in order to better understand the phenomenon of hedonic eating."
Source: Journal of Clinical Endocrinology & Metabolism
June 2012, JCEM jc.2011-3018; doi:10.1210/jc.2011-3018
"Hedonic eating is associated with increased peripheral levels of ghrelin and the endocannabinoid 2-arachidonoyl-glycerol in healthy humans. A pilot study”
Authors: Palmiero Monteleone, Pasquale Scognamiglio, Alessio Maria Monteleone, Benedetta Canestrelli, and Mario Maj