How to Keep from Losing Muscle on Empty Stomach Cardio

i see a couple options to keep you from going catabolic with empty stomach cardio, btw i use both of these in conjunction and they work very well..

1) if you can, order some bulk glutamine (around 15-20$ for 500g) and take around 5-10g before cardio, this will give your body a large amount of glutamine to use to replenish it's amino acid pool. The reason this is important is because when your body enters a catabolic state it breaks down muscle tissue into it's constitute amino acids and transports those to your liver where they are broken down into alanine and converted into glycogen via gluconeogenesis. But this can be avoided by providing your body with either protein for it to break down into amino acids or the aminos themselves. Btw, glutamine makes up about 60% of the aminos in muscle tissue and therefore is the most used amino during gluconeogenesis, that's why i recommend it.

2) Drink a whey protein shake before cardio (i prefer whey for this because whey is a fast acting protein so the aminos in it are digested within 45 minutes), this will supply your body with the aminos it needs and will spare your muscle from being burned for energy, and if your wondering if it will be counter-productive to drink a shake because the protein will be used and you won't be burning fat, don't worry, it won't unless your training with high enough intensity for it to be used to fuel gluconeogenesis, cool huh, lol. Btw, most protein shakes are infused with amino acids, just look on the jug and you'll see a list of the aminos in it, so you're getting glutamine from it.

i normally will drink a small shake (about 20g of protein), made with water and add glutamine and caffeine(if you didn't know, caffeine increases fat-oxidation, lowers perception of workout intensity, and spares muscle glycogen, making it a perfect companion during cardio), this combination increases my ability to perform cardio in both duration and intensity and gives me peace of mind knowing that my muscle has very little chance of being tapped into for energy.