I heard a guy at the gym saying it takes about 5 or 6 hours for protein to be digested - so when should i take my protein supplement, before or after lifting?

Hi:

Your guy at the gym is right - almost.  Protein is digested slowly - about 2 hours for whey, 5 hours for soy and egg, 7 hours for casein.

Research does suggest that a key in the process of muscle growth is the saturation of the muscles with essential amino acids after working out, so it does actually make sense to take a protein supplement before working out.  If you wait till afterwards, it will be hours before your muscles get the animo acids they need.

that's interesting - i'll have to tell my gym rat friends about this!

I had not realised that protein digested so slowly! 

that's really interesting - I'll have to experiment with that and see if it makes a difference.

Sounds good, but how long after working out should I have a protein shake then?

My trainer told me to take my protein shake before i work out, then have something like a banana after my workout.

Ideally you should take your protein shake a few hours before a gym session and then again after to reap the benefits. Also, try adding some carbohydrate with the shake to maximise uptake.

Right!  After a workout, assuming you've taken a protein shake beforehand, you need some carbs as quick as possible to let the muscle have the fuel it needs to grow.