Body weight refers to the mass of the individual in S.I. units of kilograms (kg). It is extremely variable both within a population and in the individual with time. It is dependent on both genetic and environmental factors.
Weight varies with height and build; attempts have been made to standardise weight independent of the latter variables to indicate nutritional state. One approach is to compare weights of populations with similar builds; however, previously, standard populations were not objectively and metrically assessed as to their build. Physique is a relatively difficult parameter to accurately and quickly quantify. Hence, the use of the body mass index, a measure of weight that is independent of height, has become a more widespread and practical guide.
In practice, the trend of weight change of an individual with time is a useful tool for monitoring pathology or therapeutic intervention. Ideally, it should be carried out by the same observer every day in standardized conditions. Yet, even weight trends must be interpreted with caution:
Nevertheless, weight is a key medical index used for:
Last reviewed 01/2018