Um, I think you must have been absent that day...
You may be suffering under this common misconception about carbs due to confusing carbs and glucose. You do need glucose to survive. your body can manufacture glucose from protein, so you don't need to eat carbs to get what you need. That's not to say the best diet has no carbs, it's just that our amazing bodies can get what we need to survive without them.
This is great news for people (like me) who no longer tolerate many carbs, I can eat ignore much of the common wisdom on fueling bike rides (and other sports) and do quite well without harming my body with the sugars and starches.
So many half-truths to sell products on the internet...after all, if it's on the internet, it MUST be true.
Glucose, sucrose, fructose, sugar, starch, etc are ALL carbohydrates, no matter the source. They are all digested into the simplest form and absorbed into the bloodstream. The only thing that really changes is the timing from ingestion to absorption. This may
have a differential effect on the blood sugar levels of those with type 2 diabetes mellitus, depending on whose research you subscribe to. The body of evidence is currently equivocal on that topic.
Yes, our bodies, under extreme conditions, do catabolize protein in a way that ultimately can generate glucose. This DOES NOT, however, happen directly from the protein in your meal. Those proteins are digested into their building blocks, just like complex carbohydrates, amino acids. At that point, the amino acids are delivered to where the body deems them most needed. The proteins catabolized and ultimately converted to glucose primarily come from the stored form of amino acids (proteins)...skeletal MUSCLE. As an active cyclist, this sounds like a rather poor choice.
We are all free to choose what ever diet we want, based on food availability and our willingness to carry other options. The nutritional guidelines published and supported by science are constantly being reevaluated based on current knowledge. These guidelines do change over time as our understanding of biochemistry, nutrition, exercise physiology (my background) and other specialties evolves.
I applaud everyone for finding what works for them but worry when basic science gets twisted beyond its intended purpose and develops into something else. Unfortunately, this too often occurs when some book, product or next best diet solution is being marketed.
Enjoy the ride,