after lifting weights, ASAP, no need to wait 30 minnutes, it should be consumed within the first 30 minnutes.
a good thing to do is to take something with you to the gym, get it immidietly. I bring a bottle of chocholate milk (im bulking).
Thing is, after you have worked out, there is a window right to your muscles, what you eat/drink will go to your muscles to build them, this window getts more and more closed the longer you wait. Liquit protein and carbs are usually through the system and at the muscles within half an hour after you drink it, as opposed to propper "food" which takes 3-4 hours. + if you drink something right after, ive heard this "window" will expand, making your real meal you eat once you get home more benificial
and banana made me come up with something.. maybe i should mix some bananas in my shake.. the only thing its low on is protein.
how much protein aprox is in a banana?
EDIT:
Banana (edible parts)
Nutritional value per 100 g
Energy 90 kcal 370 kJ
Carbohydrates 23 g
- Sugars 12 g
- Dietary fibre 2.6 g
Fat 0.3 g
Protein 1 g
Vitamin C 9 mg 15%
Potassium 358 mg 8%
thats not protein rich :S