If you find you are not gaining any weight increase your calorie intake by about 300 per day; but if you find you are gaining fat decrease it by 300 per day. (whatreallybuildsmuscle.com)
Another factor at play here is the increased energy levels that come by way of increased calorie intake. (physiqonomics.com)
That means they will fill you up without increasing your calorie intake. (coachcalorie.com)