Glucose is C6H12O6, 6 water molecules for every carbon molecule, as Carbohydrate literally means "Hydrated Carbon".
Funnily enough, the process of Glycolysis, that breaks down Glucose and Glycogen into Pyruvate is reversible, with a process caleld Glucogeonesis, which is very similar, but has about 2 or 3 subtle differences, because if it was exactly the same, you'd have a Glucose / Glycogen to Pyruvate cycle, where the end product couldn't be used for other reasons, making it a pretty redundant product and Glycolysis a pretty pointless biological function.
The breakadown of Glucose and Glycogen involves conversion of Glucose to Fructose and other stages including scavenging of Phsophates, mainly from thr Adenosine Tri-Phosphate substance that is stored in Muscle Mitochondria and helps to facilitate Muscle movement.
Some of the Phosphate is eventually tagged onto Pyruvate, which is where the energy comes from, at the end of the process. Incidentally Pyruvate can be bought as a supplement, but the consensus as I've read, is it's not that great.
The Carbon is not an energy source as I am aware, hence Carbon Dioxide, a substance the body expells.
As Humans are Carbon based life forms, then logic dictates, (well to me anyway), that if a person consumes edible Carbon from substances like Carbohydrates, there will potentially be an excess and like most excess things in the body, they get stored, excreted, sweated, urinated orbreathed out, or alternatively vomited, if the body detests them and may have zero tolerance to them, hence the expulsion of Carbon Dioxide, if excess Carbon exists in the body. the two Oxygen molecules being also potentially due to excess, where the body has no use for some of the Oxygen present, so like many things you can consume, expulsion would probably occur before some kind of storage.
The reason why you get things like Selenosis from Selenium, Copper Toxicity and Wilsons Disease from exess Copper, Gout, (from too much Xanthine from Methylxanthine consumption and Nitrogen conversion from Proteins), heavy metal toxicity, Vitaminosis, etc, are probably, (I think), because you consume so much at once, or over a prolonged period of time, your processing and waste systems are working at maximum capacity forcing the leftover unprocessed material, to be store in places like the muscles, Brain, Eyes and organs, which then results in toxicity issues, as such substances in question are normally either removed or processed. In a raw natural state, even when stored in the part(s), of the body they go when processed, you'd have a serious issue, as they aren't meant to be there unprocessed, as then they're unusable.
Think of it like taking the raw ingredients for Diesel, making some unrefined / unprocessed concoction, putting it in a car, then expecting the car to move when you turn the ignition and slip into gear. Without the refinement process first, you wouldn't have something usable by the engine.
I may have said more than I needed to, touchwood I was accurate too, but hopefully you get the gist