Blood Sugar Levels Shown to Affect Reward Preferences
Study finds people with high blood glucose are more likely to prefer future rewards
THURSDAY, Feb. 4 (HealthDay News) -- Blood glucose levels appear to affect whether a person is more likely to prefer a reward now or later, according to a study published online Jan. 20 in Psychological Science.
Xiao-Tian Wang, Ph.D., and Robert D. Dvorak from the University of South Dakota in Vermillion studied 65 undergraduate students who were asked whether they would prefer a specified sum of money tomorrow or a larger sum (14 choices ranging from $90 to $570) after a specified delay (4 to 939 days) before and after drinking a caffeine-free soda containing either sugar or an artificial sweetener.
The researchers found that after controlling for sex, age, body mass index and the taste of the drink, students whose soda contained sugar had high blood glucose levels and showed a reduced rate of future discounting, preferring to receive money at a later date. In contrast, students whose soda contained an artificial sweetener showed an increased rate of future discounting, preferring to receive money immediately.
"Our results showed that human preferences for future versus current rewards fluctuated from moment to moment based on blood glucose levels," Wang and Dvorak conclude. "This study adds to the list a metabolic mechanism of using daily fluctuating blood glucose levels as cues in regulating body-energy balance and its behavioral manifestation in future discounting."