Why there's always room for dessert: Pleasure eating triggers body's reward system



10:37 GMT, 8 May 2012

Why is it that after a huge meal you can always find a corner for a delicious dessert… even though you know you shouldn't

It's because this type of eating is motivated by pleasure rather than by hunger, scientists say.

 Your brain is wired to 'reward' you when you eat a sweet treat - even when you're full

Temptation: Your brain is wired to 'reward' you when you eat a sweet treat – even when you're full

The team from the University of Naples found that when we eat for pleasure rewarding chemical signals in the brain are activated when we eat for pleasure, which can lead to overeating and obesity. This phenomenon is known as 'hedonic hunger'.

Lead author Dr Palmiero Monteleone, said: 'It refers to the desire
to eat for pleasure, and to enjoy the taste, rather than to restore the
body's energy needs.

'For example,
desiring and eating a piece of cake even after a satiating meal is
consumption driven by pleasure and not by energy deprivation.

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-AG are involved.'

The phenomenon ultimately affects body mass and may be a factor in the continuing rise of obesity.

In the study, researchers assessed eight satiated healthy adults, aged 21-33 years, feeding them each their personal favorite food and, later, a less-palatable food of equal caloric and nutrient value.

Researchers periodically measured their 2-AG and ghrelin levels. They found the plasma levels of ghrelin and 2-AG increased during hedonic eating, with the favorite foods, but not with non-hedonic eating.

This increase suggests an activation of the chemical reward system, which overrides the body's signal that enough has been eaten to restore energy.

'Hedonic hunger may powerfully stimulate overeating in an environment where highly palatable foods are omnipresent, and contribute to the surge in obesity,' said Monteleone.

'Understanding the physiological mechanisms underlying this eating behaviour 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.'

The study will appear in the June Issue of The Endocrine Society's Journal of Clinical Endocrinology & Metabolism.