Most people are now becoming more and more concern on their relative body weight, the actual one that is more appropriate. And in order to gain a positive response to this query, several key factors and aspects to be looked into. Some of these relative aspects about that should be seen include the person’s sex, his age, the relative density of his bones and many more. Another aspect to note is the person relative body mass index at a certain age. The body mass index is one of the most reliable yardsticks in suggesting the ideal body weight of a certain person. Notwithstanding, certain studies and observations may be inferred that the body mass index provide the user a perfect and reliable measurement results. This is due to the fact that it does not allow inclusion of considerations in terms of the person’s hip ratio and muscle weight or mass. One could basically note that in comparison with the body mass index of a certain individual against that of another would be said to differ. This is essentially true as suggested by the underlying natural aspects like the person’s age, density of the bone, height and sex.