Hi! I'm 16 years old, 5ft8, I weighted about 172 lbs and because I start my diet, I went down to 157 lbs now, I have 17-18% of body fat. Am I overweight and how heavy should I be if I'm 16 years old? Also I do not play any sport but I do work out in the gym, train 1-2 body parts per day. How much protein should I intake right after my workout (I use Whey Protein Gold Standard 100%)? I don't want to gain anymore weight because of my back pain. Also, if I start my diet at the early age 15 years old until now, will it slow my body to grow? And if I got back problem,back pain, will it stop my body to grow higher? And finally, how much water should I drink per day, now I drink about 2-2.5 litres per day.