Eat to gain muscle by being conscious and smart. Loading up on protein shakes and increasing calories too much will put on belly fat, not lean muscle mass like you want.
Guys make huge mistakes in their quest to get big fast. They fall for all kinds of hype on the Internet promising significant muscular gains in a short amount of time.
Trust me, there are only two types of guys who gain muscle easily: those who are injecting steroids...and those who genetically predisposed with freaky DNA.
The rest of us have to eat to gain muscle, progressively, over a much longer period of time. (Olympic and professional athletes know they can only gain 1 to 1-1/2 lbs of rock solid muscle PER MONTH from diligent off-season training. What does that tell you?) Time, along with patience, is a major factor.
* First, get a clear and realistic vision of what you expect. The idea that you will look like a professional body builder (whose steroid dosages are tracked by a personal physician) is NOT a realistic vision.
* The more lean and defined you become, the heavier and more muscular you will look. Women are in love with the Lean Hollywood Look. This is much easier to attain than a bulky, steroid look.
* Eating to build muscle does NOT work unless you are lifting heavy and utilizing interval training workouts to increase lean muscle mass.
* Protein has been said to be the key to muscle growth, but you will have a tough time getting the ideal of 1g per pound of body weight. (For a 150 lb guy, that would be three 8oz grilled chicken breasts each day.) Just strive to get close, without force-feeding or over-eating.
* Carbs are necessary for energy to workout, but foods like pizza, spaghetti, sandwiches, and pancakes do NOT build muscle. (They are broken down and stored as male belly fat.
* Sugar foods provide absolutely NO nutritional benefits...other than tasting good. There is no reason for you to even get near things like sugar cereals, donuts, pop, pastries, or desserts if you are truly intent on eating to build muscle.
* Eat as many fresh fruits and green vegetables as you want throughout the day.