can you guys please suggest me a dieting plan or something to gain weight or to add some muscle around my body and face. I'm a 21 year old guy , very slim for my age and want to gain weight really fast without body building. Thanks in advance
If you don't want to bodybuild I understand. The idea of lifting weights for purely aesthetic reasons doesn't really appeal to me. However, there are several activities you can do that are useful, fun, and accomplish the goal you want.
Gaining weight is the easy part. Just eat. As for activities, you have some options:
If you have absolutely no idea where to begin, but like challenge and variety, Crossfit may be a good starting place. There is a lot of difference in the way different "boxes" (name for Crossfit gyms) work, and there isn't enough consistency in the programming to push through strength plateaus. If you have a well run box you will become a good athlete, otherwise you can push yourself too hard very easily. The other downside is that a Crossfit box is very expensive--though very well furnished.
In general any program you do is balanced if it has the following components:
You won't be able to gain lean mass without putting in work to tell your body to build that lean mass. It's part of the general adaptation syndrome that governs our bodies. When you add stress that tells the body the strength it has is inadequate, it will respond by building more muscle. When you add stress that tells the body you need those muscles to endure heavy stuff for a long time, it builds the energy systems in the muscle--which adds to their size but not their strength. If you add no stress to your body, it will assume the amount of muscle available is enough.
The rest is up to you. Take this as a jump off point to look into these different activities to see if it appeals to you.
If you just want to gain weight, eat more. You say you eat a lot, but with no results. That means you're not really eating a lot. Eat more. You'll put on fat.
If you want that weight gain to be muscle instead, follow Berin's advice in his answer.