User Manual

Lafayette Instrument Skinfold Caliper II
3700 Sagamore Parkway North Lafayette, IN 47904
.
Phone: [phone]
Interpretation
Without a precise norm for everyone, it seems reasonable to maintain body composition proportions
at their level at physical maturity. The average 18-22 year-old male is 15% body fat, and the average
female of the same age group is 25% fat. The standard deviation for percent fat is ±5%. Two standard
deviation units above the average (25% for men and 35% for women) is generally considered as absolute
obesity. One standard deviation above the average (20% for men and 30% for women) is considered
too fat. Most experts agree that the ideal standard upper limit for men should be 16% to 19%, and for
women 22% to 25%.
In giving advice on weight reduction, an estimated weight loss can be calculated theoretically to get
the patient down to ideal or desired weight. Using the standard of 16% for men and 23% for women, a
patient’s desired weight is calculated as follows:
Weight = actual body weight, percent fat = the estimated percent body fat
Desired Weight (men) Desired Weight (women)
(weight - (weight * % fat))/100 (weight - (weight * % fat))/100
0.84 0.77
For example, a 40-year-old male patient who is 23% fat and weighs 210 pounds would have to reduce to
192.5 pounds to attain his goal of 16% fat. A 35-year-old female who is 28% fat and weighs 145 pounds
would have to reduce to 135.6 pounds to attain her desired goal of 23% fat.
The numerator of the formulas takes all the fat weight away from the total body weight, leaving the
lean body mass. The denominator adds back the desired amount of fat weight to the lean body mass. If
another desired weight (percent fat goal) is wanted, it is simply necessary to change the fraction value in
the denominator.
This technique for estimating desirable weight is not without error, and it is suggested that two pounds
be added and subtracted from the desired weight to provide a desired weight range. For the above
example, this would mean 190.5 to 194.5 pounds for the male and 133.6 to 137.6 for the female.
Although these desired weight formulas are useful in working with patients and giving them objective
goals for fat and weight loss, they have certain limitations. Weight loss depends on calorie intake and
expenditure, but diet and exercise affect body composition differently. When weight loss comes from
diet alone, both fat and lean tissue is reduced, which exercise alone will increase and/or maintain lean
body mass and reduce body fat. Therefore, the accuracy of the ideal weight formulas depends on how
weight and fat are lost. Periodic checks of body composition during the weight reduction program will
help rene estimations.
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