Underweight is classified as having a body mass index (BMI) below 18.5. In order to preserve optimum fitness, this BMI is estimated to be less than the necessary body mass required. There are cases in which slim persons have excellent fitness, but are nevertheless counted as underweight. While obesity has been known to be one of the greatest health issues in the world, underweight conditions can also be a significant health issue.
It leads to the weakening of your immune system, raises your risk of infections, can lead to osteoporosis and fractures, and problems with fertility. It can make people more vulnerable to developing sarcopenia loss of skeletal muscle mass and strength due to aging in extreme underweight conditions, dementia, and raise the risk of early death.
For people who are underweight, weight gain is fundamental. In underweight people, safe weight gain allows them to eliminate harmful underweight-related reactions.