Navy Method Body Fat Measurement Calculator

How does the navy method body fat measurement calculator work?

This health tool can be used to determine the body fat in percentage and mass and the lean body weight. Alongside, the BMI and BMR values are calculated and a fitness level is declared. The last item in the result comprises of the minimum calorie requirement, that can be used as a starting point for those who want to consume the adequate amount of calories to maintain their weight.

The navy method body fat measurement calculator requires the following input:

■ Age and gender;

■ Weight – can be expressed in pounds or kilograms;

■ Height – can be expressed in inches or centimeters, this is used to determine BMI and BMR;

■ Neck measurement – in either inches or centimeters, by measuring the neck circumference in the middle;

■ Waist measurement – in either inches or centimeters, the tape follows the waist line and the most accurate reading is input;

■ Hip measurement – in case the gender selected is female, this extra field is required, in inches or centimeters;

■ Activity level – ranging from sedentary to extra active, with explanations for each level. This is used to determine the minimum calorie requirement.

The calculations are based on the US Navy formulas:

For men: 495 / (1.0324 - 0.19077 x (Log(Waist - Neck)) + 0.15456 x (Log(Height))) - 450  

For women: 495 / (1.29579 - 0.35004 x (Log(Waist + Hip - Neck)) + 0.22100 x (Log(Height))) - 450

The body fat percentage is then transformed according to the subject weight in body fat mass based on the following:

Body fat mass = BF% x Weight / 100

The lean body weight is computed as the difference between body weight and fat mass.

The BMI formula is weight divided by squared height.

The BMR equation gender specific:

For women: BMR = 655 + (9.6 x Weight) + (1.8 x Height) - (4.7 x Age)

For men: BMR = 66 + (13.7 x Weight) + (5 x Height) - (6.8 x Age)

Body fat percentage

This is an indicator of the general fitness level of the body and reflects the amount of fat mass to the total body mass.

There are several means of estimating body fat percentage and most of them account for the gender of the subject because females tend to have higher levels of fat due to hormonal regulation and preparation for bearing children.

Body fat is separated into two components, essential fat (which supports basic processes) and reserve or storage fat (the variable amount from the adipose tissue).

One of the most accurate methods of estimating the amount of fat is through measuring skinfolds through the caliper test which is applied in certain anatomic places. For example, the Durnin and Womersley 4 site method uses the biceps, triceps, subscapular and suprailiac sites.

Jackson and Pollock have devised other formulas for 3, 4 and 7 skinfold sites.

Subcutaneous fat can be measured through ultrasound but this is a more complex method and requires special conditions.

Example calculation

In the case of a female, aged 35, weighing 76 kg at a height of 170 cm with neck measurement of 42 cm and waist line 76 cm and hips 110 cm and lightly active:

- Your Body Fat is 29.1%;

- Body Fat: 22.12 kg;

- Lean Body Weight is: 53.88 kg;

- Your Weight is: Overweight;

- Your BMI is: 26.3;

- Your BMR is: 1,526.1 calories/day;

- Minimum Calorie requirement is: 2,098 daily calories/day.

The American Council on Exercise provides the following fitness levels:

References

1) Shake CL, Schlichting C, Mooney LW, Callahan AB, Cohen ME. (1993) Predicting percent body fat from circumference measurements. Mil Med; 158(1):26-31.

2) Jackson AS, Stanforth PR, Gagnon J, Rankinen T, Leon AS, Rao DC, Skinner JS, Bouchard C, Wilmore JH. (2002) The effect of sex, age and race on estimating percentage body fat from body mass index: The Heritage Family Study. Int J Obes Relat Metab Disord; 26(6):789-96.

3) Friedl KE. (1997) Emerging Technologies for Nutrition Research: Potential for Assessing Military Performance Capability. Institute of Medicine (US) Committee on Military Nutrition Research; Editors: Sydne J. Carlson-Newberry and Rebecca B. Costello.