How fructose, glucose affect our appetite

Scientists have disclosed how fructose and glucose have different effects on physiological and behavioral responses to food.

To assess the different effects of the two sugars on hunger and food cue responses in the brain, Kathleen A. Page and co-workers organized MRI scans on 24 people who had been given drinks sweetened with fructose on one day and glucose on another day.

Participants were shown images of high-calorie foods and then reported their level of hunger and desire for the foods. Volunteers stated greater desire and exhibited greater activity in the orbitofrontal cortex and visual cortex of the brain in response to the food images after eating fructose, compared with responses after in-taking glucose.

Further, the authors found that fructose produced a smaller plasma insulin response than glucose. When offered with a choice between delayed monetary rewards or immediate high-calorie food values, participants showed greater willingness to give up monetary rewards for food rewards after ingesting fructose than after ingesting fructose. The results provide that intake of fructose may not produce the same satiety effects as fructose, according to the authors.

Due to differences in digestion, fructose may enhance the reward value of high-calorie food and promote eating, compared with glucose.