Number of calories needed to gain weight?

Hey everybody, I have been thinking about taking up a vegetarian diet just because I believe it is so beneficial in terms of health and athletic performance. However, I was wondering how calories work with a vegetarian diet in regards to building muscle mass. I was reading one of the Thrive books by Brendan, and he said it is the quality of the food that counts and not the quantity. He was suggesting that people do not need to count their calories. I just need conformation because I have been trying to put on muscle for years and just recently started too. It was not until I started eating about 3000 calories a day. So I guess my question is on a vegetarian diet should I still be trying to consume around the same amount of calories?

Thank you

There's no specific caloric intake as there's an infinite amount of factors that affect it for each individual.

If mass is your primary goal, the calories need to be high. You should definitely be trying to consume around the same number of calories, if not more.