One indicator of good health is having an ideal or a desirable body weight (IBW or DBW) which is the weight at which the body functions best. Being underweight or overweight is a health risk.
How does one know his desirable body weight? The formulas differ by age group. Upon birth, there is a set normal birth weight (2.7 – 3.2kg). A low birthweight implies growth retardation during pregnancy and puts the newborn at risk of illnesses if growth during infancy can not make up or catch up for what is lacking, and the child will continue to be underweight or wasted. The specific normal weights for infants to young children, this depends on the sex and age of the infant and can be easily seen in the “normal” column in the WHO-Child Growth Standards used by the Barangay Nutrition Scholars (BNS). In the absence of these WHO-CGS charts, the IBW of infants (until 11 months old) is calculated as age in months divided by 2 plus 3. For children and adolescents aged 1-18 years old, the ideal weight is computed as age in years multiplied by 2 plus 8, these two numbers constant. A 3 year old then will have an ideal weight of 14 kilograms (kg). The formula indicates that yearly increments are around 2 kg every year. In practice however, for children aged 5-19 years old, the “normal” column in the WHO tables on Body Mass Index (BMI) for Age is referred to for both males and females
Different formulas can be used for adults. The most common is the Hamwi Formula where 106 pounds (lbs) is automatically allotted for the first 5 ft height of a male and 6 pounds is added for every inch above 5 ft. The same 6 pounds is deducted for every inch below 5 ft. A 5’3 male will then have an IBW of 106 + (3 x 6) = 124 lbs while a 4’11 male will have an IBW of 106 minus 6 lbs. For females, the first 5 ft is allotted 100 lbs then add or deduct 5 lbs for every inch above or below 5 ft. Another common formula is the Tanhausser’s Method where 100 is deducted from the height in centimeters. To adjust the body frame of Filipinos, 10% of the result (termed as difference in math) is further deducted. Thus, a 5’1 adult Filipino female will have an IBW of 49.4 or 50kg computed as (154.94 cm – 100) – 10% of the difference. Still, the IBW can be computed by multiplying the height in meters squared by the factor 22. Any of the above formulas may be applied but health professionals have the option to use the method that is most practical to them (FNRI,2019).
