Supplementation can turn a mediocre diet into a good one, supplementation can make getting the correct nutrients far easier than through solid food alone while adding a convenience factor that you won't have if you are preparing all your own foods yourself.

Every muscle cell in your body is primarily protein and water with a membrane made of fat holding it together. Without the relevant supply of protein your muscles will not get any bigger. Without a substantial supply of water you will not grow either and may well become dehydrated which in turn restricts your ability to function optimally never mind get bigger and stronger.

Without good fats your body is more inclined to hold onto bad fat in the hope it can manufacture the good fats it really needs, it can't. All you end up with is fat/calorie reserves which are usually stored in full view of everyone through your spare tire or fat ass or both!

To gain SIZE AND STRENGTH you need to be lifting weights that are heavy enough to make you fail relatively quickly, if you can train for a long period of time the weight is not heavy enough or your lacking intensity.

You need to train 3-5 times a week, subject to your training program and personal situation and genetics. Some people will recover faster than others, that is why some can train 3 times a week and make progress while other need to train 5 nights a week to make progress.

You also need to be taking in enough protein to allow your body to repair itself from the rigours of day to day life whilst leaving enough protein to be pushed into your muscle cells to allow them to grow, on top of recovering from the daily grind.