If the body is very thin, body mass index can be calculated, weight divided by height squared, if less than 19, it is only considered that the person is indeed very thin, this situation requires an appropriate increase in nutritional intake, such as high protein food, such as milk, yogurt, beef, eggs and such foods. In addition to increasing nutritional supplements, but also appropriate to strengthen exercise, you can exercise every day for half an hour to an hour, it is recommended to use medium-intensity exercise, such as brisk walking, jogging, swimming, cycling this kind of exercise, supplemental nutrition plus more exercise, after a long time, slowly make the physique stronger, not so thin and weak. So, only by supplementing nutrition and strengthening exercise to solve this problem.