Why you should use more maltodextrin instead of just fructose, sucrose, or glucose.

Glucose is a simple sugar and you can only absorb a fraction as much as maltodextrin before you feel sick. Maltodextrin is a starch and you can digest probably twice as much and still feel fine. Your stomach recognizes the number of molecules first, not the number of calories. Starch packs a lot more calories per molecule, as a long string of single sugars strung together, tricking the stomach and sneaking them through. Imagine eating 1,000 calories from jolly ranchers versus 1,000 calories from potatoes. Which one is going to make your stomach wretch with regret first?   

Glucose can be broken into two parts, and the part that's actually energy is dextrose. It's the right side of the molecule. "Dex" is latin for "right side". You can go buy dextrose powder no problem. So dextrose IS glucose, without being "glu"ed to the other side.  Incidentally, the name "Dexter" comes from the meaning "right-handed, skilled" if you want a way to remember all this.

If you string dextrose (which is glucose) together as a starch so you can absorb more without getting sick, it's called maltoDEXtrin. It IS dextrose, which is the usable part of glucose. 

Your stomach needs X amount of water per molecule to digest sugars and starches. Since maltodextrin is a bunch of dextrose strung together as a single molecule, it needs half as much water or less to digest it than if you just ate simple sugars like sucrose, glucose, or fructose. The pain in your stomach when eating simple sugars is your body telling you it can't get any more water to all the molecules you put in it. Those sugars are pulling water in, but there's none left to give, so you cramp and puke. If you did maltodextrin instead, your stomach can sneak the molecules by with the same amount of water or even less, no problem. 

Conclusion: Just use maltodextrin instead of getting all into glucose or dextrose. It's already what you're looking for. It turns to glucose within seconds after it passes your stomach lining and doesn't make you sick.