Doesn’t work for everybody, but the above part is not right. There is no muscle deterioration even on zero carbs per day. Why? Because your body doesn’t build muscle mass from carbohydrate. It builds it from amino acids that your body produces or gets from protein you eat (“essential amino acids”).
What does happen is people feel weaker (usually temporarily) when they start doing very low-carb because of lack of electrolytes and stored glycogen (glucose stored with water molecule in the muscle and liver tissues). The body adjusts quite easily to that.
So here is the way muscle mass and dieting work together, regardless of what kind of diet:
If you are eating at a caloric deficit, it is likely that you will lose some muscle mass (although it can be negligible if you get enough protein and you work hard physically).
If you don’t eat enough protein per day, it is likely you will lose muscle mass, regardless of whether you are eating at a deficit or not.
Energy used to actually “work” the muscles comes from four places: free blood glucose (we’re all familiar with that); stored muscle glycogen; stored liver glycogen (this is what gets “dumped” in the morning during dawn phenomenon and also why you get high BG during stress events); or fatty acid metabolism (ketones produced from stored or free fatty acids).
So, the thing is, while many people in the “traditional” nutritional and sports physiology groups stick to the old “you have to consume carbs to perform,” there is plenty of other evidence out there at this point. The Volek group from Ohio State University has produced good peer-reviewed literature on ketogenic diets and ultra-endurance sports. Summary available from ScienceDirect, with a link to the actual article.
I myself ride (and train for triathlons) at low levels of carb consumption (I’m in between your level and “ketogenic” or Bernstein levels at around 50-70 grams per day of digestible carbohydrate), and once I got used to it and was consuming enough electrolytes, I really quite enjoy it. I haven’t run a triathlon since being diagnosed, so I can’t promise you what it is going to feel like.
I can’t imagine how my energy will wain with almost eliminating carbs. Alright, the first hour should be alright, but, after that, I imagine my energy levels hitting a brick wall (aka bonking).
I would definitely not suggest trying low-carb riding for the first time during an event. I’d want to train to see how my body responds under similar circumstances. One of the advantages of what Volek (and others) call “fat adaptation” is that you don’t “bonk” when your body runs out of stored glycogen…you burn ketone bodies for fuel instead, and this isn’t limited by the amount of consumed or stored glycogen (glucose).
Anyways, it’s something you have to figure out for yourself. Lot’s of Type 1 (and even non-diabetic) athletes are now using keto or Bernstein-like diets and doing fine in endurance sports. But it does take some getting used to. I prefer it myself.