On and off throughout the past year, I have been lifting weights on and off. Now that summer vacation has started, I want to get more involved in body building. So as I lift weights, I'm planning on slowly increasing my calorie intake. In addition to this, I'm also thinking about using protein drinks...But my question is, are there any negative side affects to taking this? And would it be a good choice to start drinking protein drinks at my age (I'm 15 and turn 16 in December)?