Eating leads to widespread opioid release in the brain, which signals feelings of satiety (fullness) and pleasure, according to a study in the Journal of Neuroscience. “Together, these sensations make us more keen to eat good-tasting, as well as nourishing, food in the future,” says Lauri Nummenmaa, PhD, senior author of the study at the University of Turku in Finland.
The scientists did brain scans in 10 healthy-weight, Finnish male volunteers (ages 20 to 35) after eating pizza and after drinking a nutrition shake, which were matched for calorie and nutrient content. Both meals triggered a significant release of opioids in the brain (more-so after the pizza than nutrition shake) and increased self-reported satiety, compared to the fasted state. But, only the pizza led to a notable increase in self-reported feelings of pleasure.
This science comes with a caution to avoid overeating. “Because the body’s opioid system is involved in appetite control, its repeated overstimulation following overeating can make it less sensitive, as we’ve shown in previous research,” Nummenmaa says. “This, in turn, may lead us to crave even more pleasure from food. When coupled with increased food intake, this may contribute to obesity.”
To learn more: The Journal of Neuroscience, August 2017