“At no other time has Nature concentrated such a wealth of valuable nourishment into such a small space as in the cocoa bean”— Alexander Von Humboldt

Walk down the candy aisle of any major grocer and you will find a variety of chocolates. The overwhelming majority of these goodies are milk chocolates. If you look closely, you will also see a small selection that contains high concentrations of cocoa that range from 70 to 90 percent. Those preparations are not as popular as milk chocolate. A recent study investigated why we prefer milk chocolates over these high cocoa preparations.

The combination of cocoa, sugar, and fat in chocolate underlies chocolate’s ability to reduce tension, improve mood and elicit an addictive-like eating response. [If you would like to read more about how food affects the brain, see “Your Brain on Food.”] Cocoa contains at least ten different psychoactive compounds, such as methylxanthines (caffeine and theobromine), PEA (similar to amphetamine), and anandamide (a cannabinoid), however, the other attributes of chocolate, such as sweetness and texture, are important too. Chocolate’s allure is likely due to the synergistic interaction of fat, sugar, and these psychoactive molecules on endogenous reward systems in the brain.

A recent study attempted to determine which factor plays the biggest role in chocolate cravings. The scientists hypothesized that the amount of chocolate consumed would correlate with the increasing sugar content and decreasing cocoa and fat content of the chocolate. The subjects ate five grams of chocolate with varying amounts of cocoa (90, 85, 70 percent, and milk chocolate at 30 percent), sugar, and fat. Chocolates were tested in order from least to the most amount of sugar, and then the subjects completed standardized tests of addiction and craving using, among others, the Binge Eating Scale.

The study revealed a significant psychoactive dose-effect relationship: the subjects reported more cravings and rewarding feelings as the sugar content increased and the cocoa and fat content decreased. Overall, the sugar content, which plays a key role in chocolate’s pleasurable taste, was the most important factor in determining chocolate’s reinforcing potential.

Consuming milk chocolate, which has a higher sugar content and lower cocoa content, elicited the greatest increase, as compared to all the other chocolates, in the total number of feelings of well-being and euphoria. Previous studies have reported that these feelings are typical of the activation of both the dopaminergic and the opioid neurotransmitter systems.

Consuming chocolate containing 90 percent cocoa increased the total number of positive responses, which is surprising given its bitter taste. The higher concentrations of psychoactive compounds found in dark chocolate may explain these positive results. Studies have shown that the consumption of dark chocolate increases energetic arousal without inducing cravings for more chocolate. The stimulant effect of pure cocoa powder is likely due to the combined effects of theobromine and caffeine as well as PEA.

In conclusion, the allure of chocolate is due to the aggregate interactions of many different molecules, however, the sugar content of chocolate, more than any other molecule, was directly related to our cravings for milk chocolate and explains why we all buy and consume mostly milk chocolates.