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High Fructose Cram Session

Processed sugar isn’t just a recipe for obesity—it may also hurt your ability to learn.

With final exams bearing down, college libraries are in their twice-yearly transformation to squatter camps. Students hunker down in squalid carrels, fisting Doritos, or wander vacantly through the stacks, Diet Cokes in hand. What’s a little sinful sugar to get you across the finish line?

But that pint of Ben and Jerry’s could cost you. A new study from the University of California, Los Angeles suggests that an unhealthful diet of too few omega-3 fatty acids and too much high fructose corn syrup might do real damage to the brain’s ability to learn and recall information.

It’s long understood that eating too much sugary food can be a surefire path to diabetes and heart disease. But UCLA’s Rahul Agrawal and Fernando Gomez-Pinilla wanted to know what effect it might have on the brain. To find out, they trained two dozen rats to do a simple Barnes maze, requiring them to find a hidden escape chamber. For five days the rats slowly got faster. Then the researchers serated the rats into two groups, and deprived one group of dietary omega-3s while allowing them to binge on fructose-sweetened water. Six weeks later, they ran the maze again. Rats who’d been given plenty of omega-3s and no sugar had a relatively easy time recalling how to escape. But rats that were omega-3 deficient and hopped-up on sugar took five times as long to do so.

In post-mortems, the researchers found that the gluttonous rats had elevated levels of insulin resistance (the same condition responsible for America’s diabetes epidemic). Agrawal and Gomez-Pinalla hypothesize that insulin resistance may be linked to cognitive impairment, a decrease in brain plasticity, and perhaps even mental illness—theories that, if borne out, could have serious implications for the more than 60 percent of overweight Americans.

One bright spot, however: a regular diet of omega-3s ameliorated some of the sugar’s deleterious effects on insulin resistance and learning. So if a pack of Ding Dongs is the only thing getting you through that Chaucer cram session, do your body—and your GPA—a favor and wash it down with a little fish oil.