Trunk-to-Limb Fat Mass Ratio
The trunk-to-limb fat mass ratio divides fat mass on the trunk by fat mass on the arms and legs combined, both measured by a whole-body DXA (DEXA) scan. Higher values mean a larger share of fat on the trunk.
These percentiles are a FitnessNorms derivation from NHANES 1999-2004 DXA scans for 13,091 US adults aged 20 and over, all race and Hispanic-origin groups, using the measured DXA values and the values NCHS imputed for participants who could not be scanned; see the methodology. The NHANES scans used Hologic scanners with the Schoeller calibration; results from another DXA brand or calibration are not directly comparable.
Data source: FitnessNorms derivation from NHANES 1999-2004 DXA About this study
Reference population: US adults aged 20 and over in NHANES 1999-2004 with measured or NCHS-imputed DXA data, all race and Hispanic-origin groups
Trunk-to-Limb Fat Mass Ratio Norms Chart by Age and Sex
| Age | Sex | Percentile | ||||
|---|---|---|---|---|---|---|
| 5th | 25th | 50th | 75th | 95th | ||
| 20-24 | Male | 0.688 | 0.823 | 0.933 | 1.069 | 1.298 |
| Female | 0.529 | 0.679 | 0.787 | 0.956 | 1.243 | |
| 25-29 | Male | 0.746 | 0.909 | 1.037 | 1.179 | 1.392 |
| Female | 0.561 | 0.720 | 0.855 | 1.001 | 1.298 | |
| 30-34 | Male | 0.771 | 0.937 | 1.084 | 1.255 | 1.547 |
| Female | 0.564 | 0.723 | 0.869 | 1.018 | 1.306 | |
| 35-39 | Male | 0.770 | 0.995 | 1.174 | 1.354 | 1.571 |
| Female | 0.574 | 0.747 | 0.897 | 1.062 | 1.368 | |
| 40-44 | Male | 0.825 | 1.031 | 1.213 | 1.372 | 1.666 |
| Female | 0.594 | 0.764 | 0.911 | 1.097 | 1.370 | |
| 45-49 | Male | 0.849 | 1.085 | 1.261 | 1.442 | 1.721 |
| Female | 0.603 | 0.796 | 0.939 | 1.091 | 1.376 | |
| 50-54 | Male | 0.906 | 1.123 | 1.296 | 1.446 | 1.754 |
| Female | 0.641 | 0.826 | 0.991 | 1.160 | 1.503 | |
| 55-59 | Male | 0.928 | 1.164 | 1.317 | 1.478 | 1.756 |
| Female | 0.623 | 0.858 | 1.007 | 1.182 | 1.423 | |
| 60-64 | Male | 0.912 | 1.196 | 1.357 | 1.537 | 1.846 |
| Female | 0.675 | 0.858 | 1.013 | 1.190 | 1.459 | |
| 65-69 | Male | 0.973 | 1.200 | 1.371 | 1.566 | 1.841 |
| Female | 0.650 | 0.851 | 1.016 | 1.228 | 1.521 | |
| 70-74 | Male | 0.854 | 1.156 | 1.338 | 1.542 | 1.760 |
| Female | 0.663 | 0.889 | 1.042 | 1.210 | 1.449 | |
| 75-79 | Male | 0.863 | 1.102 | 1.283 | 1.456 | 1.738 |
| Female | 0.657 | 0.839 | 0.991 | 1.172 | 1.460 | |
| 80-84 | Male | 0.895 | 1.094 | 1.285 | 1.434 | 1.701 |
| Female | 0.602 | 0.795 | 0.959 | 1.121 | 1.532 | |
| 85+ | Male | 0.814 | 1.077 | 1.250 | 1.439 | 1.723 |
| Female | 0.608 | 0.787 | 0.954 | 1.115 | 1.463 | |
What to expect by age group
Among US adults aged 30 to 34, the middle 50% measure 0.937 to 1.255 for men and 0.723 to 1.018 for women. The median rises from 0.933 for men and 0.787 for women at 20-24 to 1.371 for men at 65-69 and 1.042 for women at 70-74. A ratio above 1 means more fat mass on the trunk than on the arms and legs combined.
| Age | Males | Females |
|---|---|---|
| 20-24 | 0.823 to 1.069 | 0.679 to 0.956 |
| 25-29 | 0.909 to 1.179 | 0.720 to 1.001 |
| 30-34 | 0.937 to 1.255 | 0.723 to 1.018 |
| 35-39 | 0.995 to 1.354 | 0.747 to 1.062 |
| 40-44 | 1.031 to 1.372 | 0.764 to 1.097 |
| 45-49 | 1.085 to 1.442 | 0.796 to 1.091 |
| 50-54 | 1.123 to 1.446 | 0.826 to 1.160 |
| 55-59 | 1.164 to 1.478 | 0.858 to 1.182 |
| 60-64 | 1.196 to 1.537 | 0.858 to 1.190 |
| 65-69 | 1.200 to 1.566 | 0.851 to 1.228 |
| 70-74 | 1.156 to 1.542 | 0.889 to 1.210 |
| 75-79 | 1.102 to 1.456 | 0.839 to 1.172 |
| 80-84 | 1.094 to 1.434 | 0.795 to 1.121 |
| 85+ | 1.077 to 1.439 | 0.787 to 1.115 |
Detailed Breakdowns
Select an age group and sex below for detailed percentile charts and distribution labels.
Frequently Asked Questions
How is the trunk-to-limb fat mass ratio calculated?
Divide trunk fat mass by the combined fat mass of both arms and both legs, using the regional results of a whole-body DXA scan. A ratio of 1.0 means the trunk and the limbs hold the same fat mass.
Can I compare my DEXA report to these values?
Only approximately. DXA results depend on the scanner brand, software and calibration. These values come from Hologic scanners using the Schoeller calibration in NHANES 1999-2004. A GE Lunar scan, or a Hologic scan with a different calibration, can report a different regional fat for the same body, so a small difference from these percentiles may reflect the scanner rather than the body.
How is this different from the trunk-to-leg fat percent ratio?
This ratio compares fat masses in kilograms, so it depends on how much tissue each region holds. The trunk-to-leg fat percent ratio compares the fat percentage of the trunk with the fat percentage of the legs.
How do these values relate to Kelly et al. 2009?
Kelly et al. 2009 fitted separate reference curves for non-Hispanic White, non-Hispanic Black and Mexican American adults from the same NHANES scans. This page pools all US adults, as the site's other NHANES measures do, so its values differ from any one of Kelly's curves. The method behind it reproduces the National Center for Health Statistics' own published percentiles for the same survey years; see the methodology.