High-sugar diets are bad for your waistline but they may be bad for your brain too.

Researchers trained rats to successfully navigate a maze and then for six weeks the rats' water was replaced with syrups that were 15 percent fructose. But half the rodents were also given flaxseed oil and fish oil—both rich in omega-3 fatty acids, which may protect against damage to synapses in the brain.

After six weeks of the fructose syrup, all the rats were slower at running the maze. However, those that had received omega-3s were slightly faster than their counterparts. 

Lesson: Don't replace your water with syrup.

Read Can Sugar Make You Stupid? "High Concern" in Wake of Rat Study by Charles Q. Choi, National Geographic News - ignore the spelling error in the article, all their money is going into "Doomsday Preppers" these days, not editors.

And then read Confusing messages about sugar are stupid by David Despain at Evolving Science and 

Sugar makes embargoes stupid, and doesn’t do wonders for a press release, either by Ivan Oransky at Embargo Watch and

Does Sugar Make Journalists Stupid? Not as Much as You Might Think by Deborah Blum at Knight Journalism Science Tracker

All make the point I started way back when Big Bleached White Sugar started successfully marketing the notion that high fructose corn sugar was somehow worse for you than bleached table sugar - it's rubbish, just don't eat a lot of sugar either way.