Whatever your estimated maintenance level is, you’d now have to add 250-500 calories to it and start to consume this number of calories every day. (For example, if your estimated calorie maintenance level was 2000 calories, you’d now begin to eat between 2250-2500 calories per day.) You will now be consuming the excess of calories required for your body to build new muscle. You should end up gaining weight at the ideal rate of between 0.5 and 1 full pound per week.
Of course, you must keep in mind that this is nothing but an estimate. The only way to ensure that you are A) eating an excess of calories and B) not eating too BIG of an excess of calories is by keeping track of what your weight is doing and then adjust calorie intake accordingly if needed. Here’s what I mean…
If you are gaining somewhere between 0.5 and 1 pound per week, you are doing everything perfectly. All you need to do now is continue eating this amount of calories every day while at the same time continuing to weight train properly. If you ever stop gaining weight at this ideal rate (for at least 2 or 3 weeks in a row), just adjust your calorie intake until you are back to gaining in this 0.5 – 1 pound per week range.
If you are gaining more than 1 full pound per week for more than a couple of weeks in a row, you are probably eating too much and will end up gaining too much extra fat. Slightly lower your daily calorie intake (by about 250 calories) and see what your weight does then after a week or two. Still gaining too much? Lower it some more. Basically, adjust your calorie intake until you are gaining in the ideal 0.5 -1 pound per week range.
If you are gaining less than 0.5 pounds per week for a couple of weeks in a row, you are probably not eating enough. Slightly increase your daily calorie intake (by about 250 calories) and see what your weight does then after a week or two. Still not gaining in the 0.5 – 1 pound per week range? Increase it a little more. Basically, adjust your calorie intake until you are gaining in the ideal 0.5 – 1 pound per week range.