anecdotally, i always struggled focusing with caffeine. look into green tea; it's not only very healthy but it's more of a calm and alert type of focused, no jitters or bursts of energy. 3-5 cups seem to work best for me.
Pretty cool.<p>If you want to replicate this, please remember that they consumed only glucose!! Fructose, which is present in equal amounts in table sugar, sucrose, is definitely not good for you (unless you eat fibre with it, like in fruits). It's processed solely in the liver and in a way analogous to ethanol. You can get fatty liver from too much HFCS.<p>If you're interested, check out this review by Dr. Robert Lustig: <a href="http://www.scribd.com/doc/36173697/Bariatrician-Fructose" rel="nofollow">http://www.scribd.com/doc/36173697/Bariatrician-Fructose</a>
...and speed?<p>Of course, one might first want to consider the depreciated effectiveness—relatively speaking—of the sugar, and of the caffeine, were they to combine all three.<p>Related: Kumail Nanjiani on new drug called cheese
<a href="http://www.youtube.com/watch?v=k1cvKcGVy6k" rel="nofollow">http://www.youtube.com/watch?v=k1cvKcGVy6k</a>