Bulking is a muscle-gaining phase. It is simply eating more calories than your body needs, for a set period of time (usually 3-6 months). These extra calories provide your body with the necessary fuel to boost muscle size and strength while weight-training. Most people bulk when they are naturally underweight and have a hard time putting on muscle.
Imagine you are building a house, but you want to make the house bigger and build it faster… you will need more bricks and more help. In this example, the house is your body, and the (right) foods are the extra bricks and help.
But there is a right way to bulk. You don’t want to just start eating everything in sight, and you don’t want to eat just any food either. It's important to focus on nutritious choices like lean proteins, whole grains, and fruits and vegetables.
It is normal to gain some fat when bulking. To make sure you don’t go overboard, most people eat around 300-400 calories above their normal caloric intake. To avoid ruining your bulking journey, avoid the many bulking myths that go around.