jonner said:
i am wondering how essential are these to gaining muscle?
i know good diet is very important
but just wondering...the most important are calories and protein. just how important are carbs n fruits / veggies?
How 'important are they to muscle gains"?
To be completely honest - Not very...

You could gain muscle eating a really crappy diet as long as you are:
1. meeting your calorie needs
2. meeting your protein requirements
3. training effectively (frequency, volume, load, intensity etc)
4. Hormonally/physiologically capable
*
But how important are they to general health?
Very.
They are a fantastic source of fiber, vitamins, minerals, phyto-nutrients etc etc... They have been shown to decrease your risk of developing a wide variety of diseases/conditions (eg: cancers, cardiovascular disease) and have also been shown to decrease and control/help with things like blood pressure, cholesterol levels, insulin regulation etc...
The
* is then because, indirectly, this "health" effect will feed back onto your physiological and hormonal status - as when you are in good health you will create a better physiological environment for growth.