The bottom line is that we need to consult with nutritionists, read books, and select our foods with considerable care taking note of their ingredients and the level of processing involved.
There is a plethora of excellent books on nutrition available. A good one to start with is Sugar Blues, by William Dufty published by Chilton Book Company in Radnor Pennsylvania in 1975.
Stimulation through other modalities, particularly the Haptic can raise the arousal level and hence improve the level of perceptual organization and understanding.
Tactile: One of the best methods to improve attention is message. Of course, this is also one of the best ways to be sent to jail.