1. Sustagen is definitely not a good post-exercise shake to have. It is too high is sugars and carbs, and contains inferior quality protein. There are far better options available on the market. If you visit your local health food store they will be able to offer you a much better option.
I have noticed that many doctors and nutritionists recommend Sustagen and it's simply because they don't know any better!
2. If your goal is to build muscle and/ or improve sports performance then I would definitely suggest having your post-exercise shake within 30 mins of exercise. However, if you goal is to burn off maximum amounts of body fat then I suggest waiting 30 mins (but no longer) before having your shake.
