Want to lose fat, get up, do your cardio, eat breakfast within 20 minutes. After lifting weights and depleting your muscle glycogen do more cardio, eat within 20 minutes of getting done. Some believe that in order to avoid muscle waisting on the morning cardio that you should take some amino acids before you begin, I have done that and I have not done that and I have never seen any deference.
this is a very controversial subject and always will be. The body at rest burns almost 100% calories from fat. However, when you become active that number changes depending on intensity. For example, a marathon runner at maximum intensity will be burning almost 100% carbohydrates for energy. A moderate intensity cardio activity like jogging or incline walking will (depending on the person) use 60-70% fat and 30-40% carbohydrates (in the form of glycogen) for energy. The body is an amazing machine and it is very difficult for it to go into a catabolic state. That being said, if you are on a completely empty stomach, already on a low carbohydrate diet, and all your glycogen is depleted, that same moderate intensity activity will use more in the range of 80-90% fat and 10-20% muscle proteins for energy. So to answer your question, you will burn more fat on an empty stomach and glycogen depleted but only at the cost of 10-20% muscle. Fat loss is dependent on calories burnt and that will remain the same. I see no real advantage for somebody to do cardio on an empty stomach with no glycogen stores to use. My suggestion is to get some aminos in you and a light amount of carbohydrates before doing a low to moderate intensity cardio for a longer duration of time.
It depends what your priority is. If wanna loose fat no matter what than cardio on an empty stomag is the way to go but if you wanna keep that hard earned muscle mass than I would avoid it. When you wake up your body is in a very catabolic state, by doing cardio withoud getting any food would make it worse which could lead to muscle breakdown for energy.
Try some HIIT, imo a far better choice than cardio on a empty stomag.
Good point Philo!
About the 8oz water and whey that you mentioned miami is the idea that the amino acids in the whey can be converted to carbohydrates in the body if needed and the body can then use that for energy. Fact is, if you are already on a calorie restricted/low carbohydrate diet, you are not going to store your carbohydrates as fat anyways. I think that it would be better than nothing but I think the perfect combination would be to combine it with a light amount of carbohydrates.