Being overweight or underweight both have their health risks. We know that being overweight is not only “unfashionable” but it is associated with higher risks of chronic diseases such as heart disease, diabetes and cancer, etc. On the other hand, being underweight puts a person at higher risks of infection because the immune system is weakened. Underweight is also associated with lower energy, osteoporosis, absence of menstruation in female, hair loss and anemia.
So how much should you weigh? The Body Mass Index (BMI) is used to estimate the healthy body weight of a person. It is calculated by taking body weight in kilogram divided by the square of your height in meters.
BMI = weight (kg) ÷ height2 (m2)
A BMI that falls between 18.5 and 25 indicates optimal weight. A BMI greater than 25 suggests overweight. BMI over 30 suggests the person is obese. Keep in mind, the BMI does not assess body composition. Not all weight gain is due to excess fat. The increase in weight could be fat, muscle or fluid.
A body builder could have mostly lean body mass with no excess fat and have a high BMI. This is because muscles weigh more than fat. The easiest way to know your body composition is to buy a scale with the function to measure your percent body fat. But again, this is just an estimate for body fat and is not an absolute scientific method for determining your body composition.