This is a loaded question and can not be answered directly in a yes or no answer.... I'll say this and then leave it -Originally Posted by Machher
It is not ABSOLUTELY NECESSARY.... but pre and post workout nutrition is VERY IMPORTANT in how you train and the effect of that training.
There are MANY things that will alter the effects of your training -My friend and i were just talking and he said "i eat a can of tuna after every workout". He was 190 lbs when he was bulking and age 15 and only 5'10". Im thinking mabye this is the reason why he is substantially larger than me and most people. Obviously he has been weight training about 3 or 4 months more than me. But i really doubt 3 or 4 months could result in 20 lbs. I mean ive been up on the protein intake but since my next meal would come 2 or more hours after my workout im not optimizing my gains my having a post w/o shake/meal.
Total nutrition (for your entire day)
Pre and post workout nutrition (esp. pre workout!)
Stage of growth/puberty
Time of training (how long you workout, how many times a week)
Type of training (sets, reps etc)
Other training you do (cardio, sports)
Time you HAVE been training (months vs years)
and... drugs (steroids etc)
Your friends genetics may be VERY different to your genetics - and he might be going through a growth spurt whilst you are not. Don't compare yourself to him!
Don't get caught up in numbers or diets at your stage in life - just focus on training hard and eating well. The gains will come naturally (growth will do that for you! ).
However, I do suggest you make sure your pre and post workout meals are sufficient in both carbs and proteins to help you train hard and recover from that training.