You answered the reason behind gaining muscles in 3 months yourself. "Protein Powder". (Even if you don't, you still do gain muscles - which is only logical since you are working out - but they won't show - the point which I embedded in the 'framing aspect' of your body).I completely disagree, you can absolutely gain muscle in three months. Ofcourse you cannot become a proper bodybuilder in 3-6 months, that takes years, but putting on 15-20 lbs of muscle in the first 3 months, is not that hard (I did it). The main reason in your diet that I can think of that contributed to you not gaining weight, is obviously the fact that you were not eating enough. I gained about 20 pounds in the first 3 months that I started working out, but along with the working out, I was taking protein powder every day, eating multiple eggs every day and drinking chocolate milk 3 times a day along with regular lunch and dinner.
You said it yourself, your body is getting in shape but not putting on much muscle which tells me you need more calories. You need a calorie surplus and plenty of proteins to build muscle, ideally 1 g for every lb of your body weight if not more.
So yeah keep working out hard, up your diet and there is no reason why you wouldn't see results.
P.S it is easiest to gain muscle and get big when you are starting out. After that it keeps getting more and more difficult to put on more muscle, which is why people resolve to steroids because they want to overcome their natural testosterone limitations.
I am completely against using other 'manufactured' means of protein. So lets just stop right here (and its not open for debate with me). If someone wants to use them, its his choice. I would prefer 'slower gains' over it any day, with proper regular food.
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If you are curious why I don't prefer manufactured material, then two reasons:
- No need to use them unless absolutely necessary, which they are not.
- These 'quicker gains' are the reason that when you leave bodybuilding, your muscles start to loosen up, and fall down like old people.
As for working hard, yea, sure. There will be a time in your life when you will consider that a possibility. And then there will be a time when you will be so busy, that you will barely get enough time for Exercise. If you are former, by all means, work hard. If you are latter, even if you take it slow you will still gain, and stay fit. And that's what matters.