Beware: Fructose Can Make You Hungry, Study Finds

Twenty healthy adults were included in the featured study, published in the journal JAMA on January 2.3 fMRI was used to measure the hypothalamus response when the volunteers consumed a beverage containing identical amounts of either fructose or glucose (75 grams). The two drinks were given in random order to all participants during testing sessions spaced eight months apart.

Your hypothalamus helps regulate hunger-related signals involving a number of hormones, including insulin, leptin, and ghrelin. The scans revealed that when drinking glucose, within 15 minutes the activity in the area of the brain involved with reward and desire for food was suppressed, which leads to a feeling of fullness or satiety. According to co-author Dr. Robert Sherwin:4

"With fructose, we don't see those changes. As a result, the desire to eat continues — it isn't turned off."

In fact, fructose not only did not suppress hypothalamic activity, it actually caused a small spike instead. Furthermore, glucose boosted the links between the hypothalamus, thalamus, and striatum, while fructose strengthened the connectivity between the hypothalamus and thalamus, but not the striatum. This is important, as the striatum also deactivates once your body senses it has eaten enough... According to the authors:

"These findings suggest that ingestion of glucose, but not fructose, initiates a coordinated response between the homeostatic-striatal network that regulates feeding behavior."

What all this means in everyday terms is that when you consume fructose, you may actually be "programming" your body to consume more calories, as fructose fails to trigger that feeling of fullness, and may even trigger continued hunger pangs.