Article in English: If you're trying to bulk up because you're too lean, or you're trying to gain muscle, it's important to make sure your body is ready for gaining weight in the healthiest possible way. Just because you "look skinny" doesn't mean you have a BMI that's optimal for weight gain, and you might be doing yourself an unhealthy disservice by trying to gain before you get into shape. While it's best to visit a nutritionist first, you can measure your BMI yourself with the following calculation::  Your weight in kg (or weight in pounds divided by about 2.2), divided by Your height in meters squared If your BMI is between 18.5 and 24.9, you're at a low-normal body weight, which means you can safely gain weight, with the proper nutrition and guidance. Muscle can only be built when you create a calorie surplus, then work out in targeted ways to promote muscle growth in your body. The difference between gaining muscle and gaining fat requires that you calculate how many calories you'll need to eat to gain muscle effectively, and making sure you eat the right kinds of foods. To calculate the amount of calories you'll need: Multiply your bodyweight in pounds by 20. This is the amount of calories you'll need to eat on days that you work out, to gain muscle. If you want to build muscle and gain weight, it's absolutely essential that you take in enough protein to promote muscle growth. Without the proper amount of protein, you can do damage to your muscles by over-exerting them. To find out how much lean protein you'll need, multiply your bodyweight in pounds by about 1.5 to find out the number of grams of protein you'll need to consume in a day. Make friends with chicken and peanut butter. Lean in fat, but high in protein, these are easy-to-eat and widely available ways of making sure that you get enough protein in your diet. . An extremely common way of bulking up and gaining muscle mass after workouts is to use a protein supplement to stimulate muscle growth. Protein whey powders are widely available, which allow you to mix up...

Summary in Chinese:
先计算自己的身体质量指数（BMI）。 计算锻炼肌肉所需的卡路里摄入量。 计算蛋白质需求。 饭后喝乳清蛋白奶昔 吃低血糖、消化速度慢的碳水化合物。 通过摄入脂肪，刺激睾丸素的分泌。 制定举重或训练方案 服用纤维补充剂。