relative_fat_mass: Relative Fat Mass (RFM)

In cliot: Clinical Indices and Outcomes Tools

Relative Fat Mass (RFM)

Description

Calculates the Relative Fat Mass (RFM), an estimator of whole-body fat percentage based on the ratio of height to waist circumference. It has been shown to be more accurate than BMI for diagnosing obesity.

Usage

relative_fat_mass(sex, height, waist, units = "cm")

Arguments

sex	String. Patient sex ("Male" or "Female").
height	Numeric. Height. (Units must match waist).
waist	Numeric. Waist circumference. (Units must match height).
units	String. Units of measurement (e.g., "cm" or "in"). Used for display only; the ratio is unit-independent as long as both inputs match.

Details

The formula is:

• Men: 64 - (20 \times \frac{Height}{Waist})

• Women: 76 - (20 \times \frac{Height}{Waist})

Cutoffs for obesity are typically cited as \ge 22.8% for men and \ge 33.9% for women.

Value

A list containing:

RFM_Percentage	The estimated body fat percentage.
Interpretation	Classification as Obese or Non-Obese based on validation cutoffs.

References

Woolcott OO, Bergman RN. Relative fat mass (RFM) as a new estimator of whole-body fat percentage A cross-sectional study in American adult individuals. Sci Rep. 2018;8(1):10980. doi:10.1038/s41598-018-29362-1

Examples

# Example 1: Male
# Height 180 cm, Waist 90 cm (Ratio 2.0)
# RFM = 64 - (20 * 2) = 24%
relative_fat_mass("male", 180, 90)

# Example 2: Female
# Height 165 cm, Waist 80 cm (Ratio 2.06)
# RFM = 76 - (20 * 2.06) = 34.8%
relative_fat_mass("female", 165, 80)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.