I started working out quite recently and my trainer at the gym gave me the following diet plan as soon as I joined:
As you can see, most of the items are regular day to day meals (I'm an Indian and the menu is mostly Indian cuisine). I try my best to follow this plan. Since I'm lactose intolerant, I replaced Milk with Soy Milk. My intention of joining a gym was simple - workout to keep me fit (and keep my tummy flat). But seeing other folks there, I got motivated and asked my trainer how to put on a couple of inches on my chest, one inch on my biceps and half to three-quarter of an inch on my forearms. He immediately suggested taking protein supplements. I have seen my cousin (who was quite a body builder in his early youth) who now has a sagging body which he thinks is the result of taking supplements earlier. I don't want that to happen to me. Now, after about 4 months of regular workouts, I have gained roughly half an inch on my chest and biceps and about a quarter of an inch on my forearm. I did get a few tips from here and here, but nothing specific to my case.
How right was my trainer? Is it hard to achieve my target with a supplement-free diet?
P.S.: I'm a 27 year old, measuring 170cms (5'7") in height and weighing 58 kgs.