How to gain muscle?

My boyfriend is trying to bulk up he says he needs 4000 cal a day to build muscle. Am I wrong in saying that he will gain weight but in fat not in muscle trying to be supportive here but 4000 cal a day.......kinda high no?

In my opinion, and limited knowledge from the last time I was trying to build muscle, here's what I found.

You do need extra calories to build muscle, but you need to work out, or else it will turn to fat.  Depending on his size, and how many calories he already burns in a day, 4000 may not be all that high.  For instance, a 190 lb very active male will burn 3500 calories in a day, so upping that to 4000 while adding in weight training could be fine.  Seems high but it might not be.  I don't need to eat more because I have all of this stored fat that can be used.

Most of the additional calories should be extra quality protein.  You won't gain much muscle feasting on 4000 calories of cola and cake.  Also, if he drinks, thats out too.  Alcohol reduces testosterone so it will be harder to build muscle.  As a computer programmer, we have the line "Garbage in, garbage out".  Same goes with your body.  If you don't feed it right, you aren't going to get what you thought you were.

If you go to the 'Tools' section and do 'Expenditure' you can put in his information to see what he's burning now and then he can better judge how much additional he should eat.  Something like Body for Life or Tom Venuto's Bun the Fat Feed the Muscle eBook are good information.  I forget which one, it is, but it tells you what to eat if you aren't trying to lose weight and instead are just trying to build muscle.

Claudius is correct.  You cannot gain muscle very well while on a calorie defecit unless you are a beginner.  As a beginner it is possible to lose fat and gain muscle at the same time while on a defecit but that usually doesnt last more than 6 months to a year.

After that you have to cycle between bulking and cutting.  While bulking you are actually on a calorie surplus (clean calories as claudius mentioned) which will help build muscle but will also build a little bit of fat as well.  After he obtains the amount of muscle he wants then he need to go on a cutting stage where he is on a calorie defecit of about 500 calories a day while still lifting weights in order to keep his muscle gains.  As we all know, cutting will burn the fat off and he will soon show the muscle definition much better especially in the mid section and the abs will soon start to pop out and the much desired 6 pack will appear.  In order for the 6 pack to appear he will probably need to be around 10% body fat.

So to sum it up, without knowing his stats we cannot say that 4000 calories is to high for him or not but it is a definite possiblity.  Yes it seems like a lot but us guys burn a lot more calories than you gals especially when trying to pack on the muscle.