Hi Hurdity!
Have to disagree. I don't think you lose muscle on low carb. Perhaps on low cal diets.
My understanding - on a very simple and basic level ( not even mentioning all the bodyweight/glycogen stuff, which is far too techy for me) ... is this.
If you are on a low calorie diet, your body first burn the carbs you ARE still eating for fuel, followed by muscle tissue, and only after that, it burns fat.
However, if you starve yourself, (ie no recently eaten carb stores) you lose muscle, water, then fat.
On low carb diets, there are no carbs in your body to burn but plenty of fat stores, as your body
automatically burns fat for fuel. And it burns it quickly. Only once the fat stores are depleted do you lose muscle tissue. You eat fat, to lose fat.
Anyone interested should read Gary Taubes' Why we get Fat, and Good Calories, Bad Calories.
All I know is I am eating lots, (apart from bread, potatoes, rice, sugar, cakes, sweets etc..and hey, where is the loss) I never go hungry, eat veg, no fasts.... and my waist is down by three inches!
Edit: My spelling!! aaargh