Posted 06.15.2015 | by AMRA


Eating is often an enjoyable experience, and at times we eat more for pleasure (“hedonic eating”) than to provide nutrition or reduce hunger. Since pleasure occurs in response to the brain’s release of endogenous opioids (morphine-like neurotransmitters manufactured in the brain), the opioid system plays an important role in hedonic eating. This activity can be measured indirectly by administering naltrexone, an opioid-blocking drug that triggers cortisol secretion and sensations of nausea.

Prior research has shown that overweight women with larger cortisol or nausea responses to naltrexone are more prone to binge and emotional eating and less likely to gain weight during a mindfulness-based overeating intervention. Mason et al. [Appetite] sought to replicate and extend these findings in a large-scale randomized, controlled study of weight-loss programs with and without a mindfulness component.

Eighty-eight obese women (mean age = 47, mean BMI = 36 kg/m2) were randomly assigned to five-month diet-and-exercise-based weight-loss programs which included either a mindfulness component (based on MBSR and MB-EAT) or an active control component that included cognitive-behavioral techniques and progressive muscle relaxation.

Both programs involved sixteen 2 to 2.5 hour-long group sessions and one all-day session. Prior to randomization, participants were assessed for their naltrexone-induced salivary cortisol and nausea responses. Participants self-rated their food addiction, binge-eating, and reward-based, mindful, and emotional eating before and after treatment.

Participants’ naltrexone-induced cortisol responses were significantly correlated positively with reward-based eating and food addiction, and negatively with mindful eating. Participants with the largest cortisol responses in the mindfulness group showed significantly greater reduction in food addiction symptoms than participants with the largest cortisol responses in the control group.

Women who experienced naltrexone-induced nausea reported a statistically greater reduction of food addiction symptoms in the mindfulness condition than in the control condition. They also trended towards greater weight loss, losing an average of 10 lbs., whereas their control peers lost only an average of 4 lbs.

The study supports the use of naltrexone reactivity as a biomarker for hedonic eating, and supports the hypothesis that obese female hedonic eaters may derive greater benefit in terms of weight loss and reduced addictive eating from eating programs with a mindfulness component.


Mason, A. E., Lustig, R. H., Brown, R. R., Acree, M., Bacchetti, P., Moran, P. J., . . . Hecht, F. M. (2015). Acute responses to opioidergic blockade as a biomarker of hedonic eating among obese women enrolled in a mindfulness-based weight loss intervention trial. Appetite.

[Link to abstract]