Step 2 in glycolysis turns glucose 6-phosphate into fructose 6-phosphate. And I'm not convinced that every glucose molecule undergoes glycolysis. According to the MD in the video (minute 45 or so), 80% of glucose gets turned to CO2 and water by the organs in the body before the rest of the glucose even makes it to the liver, where eventually, ~.4% of it turns into VLDL (which is bad for you). You only need a bit of pyruvate (the end product of glycolysis) to get the Krebs cycle going, and then that takes care of the glucose, turning it into CO2 and water, without turning it into fructose in the process. And at no point is there any native fructose involved. And besides, in the video, it says fructose can't be metabolized by the brain.

I'd also like to point out I'm not drinking a shitload of this stuff all at once. The reason I avoid this is to avoid an insulin spike, which would, without question, defeat the purpose of using dextrose.

While correct in some details, yours is an incorrect description of the bigger picture of glucose catabolism. Pyruvate is consumed the TCA (Krebs) cycle, so to say that you only need a "little" is like saying you only need a "little" gas to run your car. Your car runs on gas, consuming it. The Krebs cycle runs on pyruvate, consuming it.

Glucose gets broken down into pyruvate via glycolysis, which is by far the primary way in which you generate pyruvate. This process generates a bit of energy, but the vast majority of ATP is generated during the Krebs cycle, which is where glucose metabolites (namely, pyruvate) get oxidized into CO2 and H20.

To respond more directly to your point: if 80% of glucose is immediately metabolized to CO2 and H20 (I don't recall but I'll take your word), that means that 80% of glucose enters the body, undergoes glycolysis, and then enters the TCA cycle. This means that 80% of the glucose in your body is quickly converted into fructose (yes, F6P). You could easily make this into a pure fructose molecule with a phosphatase (though this doesn't happen in vivo). The upside is that phosphorylated sugars cannot be transported by facilitated diffusion, so F6P will remain intracellular.

If you watch the video linked in the parent post, it claims/explains that doing the same with fructose would not be equivalent.

If you carefully read my post, where I emphasize that you restrict yourself to 250kcal of either, I think you'll find that we're all in agreement.

The video explains why fructose drives you to eat more (namely, it doesn't fulfill the hormonal role that glucose does). It also states that fructose is more likely to form advanced glycation endproducts, but this is far less important than the hormonal differences.

So from all practical viewpoints, I agree with you. Fructose is way worse! From the most limited perspective (basically, lock someone up and feed them 250kcal of glucose vs 250kcal fructose and don't let them have additional food), they will be very similar.