Its so confusin, some people say cardio is catabolic, some say it doesnt matter because its all a matter of Calories in vs Calories out, some say never to do it after weight lifting because you will be burning muscle??? Whats the deal here, there are so many mixed opinions its hard to buckle down and choose one. What are your opinions on this?? What about nutrition when it comes to cardio? Post Workout shake after?

I used to do cardio in the morning on an empty stomach and a l;ittle bit of weights but not much, I lost weight but I lost alot of muscle too, so Maybe just adding weight trainig to the equation will balance me out.

Your opinions please.

OK, its all relative to your goals. If you are bulking up, running your ass off will confuse your body and make the muscle building process difficult. If you want to shed fat, cardio is a very helpful tool. The key to not losing muscle though is keeping those intense weight lifting sessions 3-4 times a week. I lift 3 times a week, run after every session, do HIIT on 2 off days, run 6-8 miles on another off day, and I haven't lost a shred of muscle.

Substrate utilization during cardio will vary depending on your intensity. For example, the more intense the activity (like sprinting), the more glycogen (stored carbohydrates) your body is using; while lower intensity will use a higher ratio of fat as fuel. Overall though, the substrate utilized during exercise doesn't matter - it is indeed calories in v.s. calories out. The only time your body would go in a muscularly catabolic state is if you're doing high-intense cardio with your glycogen stores on empty.

It's fine to do a short, light session of cardio after weight lifting. Aside from the fat burning effects, you get the added benefit of increased blood flow, oxygenation of the muscles, and more efficient nutrient partitioning. Increased blood flow alows for better recovery and is just all around good for the muscles you just worked out.

Now with post-workout nutrition, your goal is to replenish your glycogen stores as quickly as possible because your body is in a vulnerable state. Having a high carbohydrate intake (especially starchy ones) will definitely help, and they don't necessarily all have to be high-GI.

The reason why people take whey protein shakes after their workout is to help repair muscle tissue with amino acids. Whey is digested quickly, especially with water.

Steer clear of consuming fats post-workout.

What type of cardio do you do after youre lifting sessions? Do you immediatly have your PWO shake after lifting then do cardio?
My goal is to lose fat and maintain muscle so I guess some light intensity after workout is ok and high intensity like HIIT for off days.
Sounds about right.

I do my lifting, then a 20 minute run, then have my dextrose/whey shake. On off days, I do HIIT, and still have the same dextrose/whey shake, so you are on the right thought track.