I am too thin, with a height of 170cm and a weight of less than 100J. I am a thin man, and I am very distressed. I can't go to the gym often because of my work. How can I keep fit?

Too thin for a reason. Poor absorption, the body does not exercise often, and it needs less energy. Naturally, it does not absorb, so it is not fat. If you want to gain weight and muscle, you must break the previous daily habits and consume a lot every day, so that your body can gradually get used to absorbing more food to supply the energy your body needs now. Over time, your body is used to absorbing a lot of energy. At this time, if you exercise and absorb again, your body contour will increase rapidly. To increase body intake, you must exercise more, consume energy, and be more eager to consume energy. You'd better spend 1-2 hours exercising after work, provided that your work is not very tiring. Go jogging around the community at night, or do push-ups at home, 100-200, uninterrupted, one group 10, and the rest time should not exceed 1 minute, and then continue.