Trunk-to-Leg Fat Percent Ratio
The trunk-to-leg fat percent ratio divides the percentage of fat in the trunk region by the percentage of fat in both legs combined, both measured by a whole-body DXA (DEXA) scan. Unlike the trunk-to-limb fat mass ratio, it compares fat percentages rather than fat masses.
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-Leg Fat Percent Ratio Norms Chart by Age and Sex
| Age | Sex | Percentile | ||||
|---|---|---|---|---|---|---|
| 5th | 25th | 50th | 75th | 95th | ||
| 20-24 | Male | 0.691 | 0.805 | 0.894 | 1.001 | 1.161 |
| Female | 0.566 | 0.685 | 0.793 | 0.924 | 1.090 | |
| 25-29 | Male | 0.736 | 0.876 | 0.972 | 1.069 | 1.208 |
| Female | 0.586 | 0.731 | 0.847 | 0.955 | 1.135 | |
| 30-34 | Male | 0.753 | 0.884 | 0.995 | 1.120 | 1.325 |
| Female | 0.597 | 0.724 | 0.855 | 0.966 | 1.139 | |
| 35-39 | Male | 0.753 | 0.942 | 1.060 | 1.166 | 1.312 |
| Female | 0.595 | 0.736 | 0.872 | 0.986 | 1.144 | |
| 40-44 | Male | 0.798 | 0.955 | 1.074 | 1.193 | 1.370 |
| Female | 0.599 | 0.748 | 0.874 | 0.986 | 1.152 | |
| 45-49 | Male | 0.797 | 0.969 | 1.106 | 1.225 | 1.416 |
| Female | 0.606 | 0.785 | 0.896 | 0.982 | 1.166 | |
| 50-54 | Male | 0.841 | 1.003 | 1.107 | 1.231 | 1.421 |
| Female | 0.620 | 0.803 | 0.908 | 1.003 | 1.209 | |
| 55-59 | Male | 0.864 | 1.033 | 1.130 | 1.231 | 1.418 |
| Female | 0.669 | 0.831 | 0.923 | 1.019 | 1.179 | |
| 60-64 | Male | 0.831 | 1.043 | 1.133 | 1.254 | 1.469 |
| Female | 0.687 | 0.848 | 0.932 | 1.020 | 1.198 | |
| 65-69 | Male | 0.874 | 1.034 | 1.142 | 1.251 | 1.486 |
| Female | 0.673 | 0.831 | 0.914 | 1.029 | 1.202 | |
| 70-74 | Male | 0.803 | 0.988 | 1.103 | 1.237 | 1.419 |
| Female | 0.677 | 0.830 | 0.922 | 1.010 | 1.158 | |
| 75-79 | Male | 0.798 | 0.967 | 1.081 | 1.194 | 1.385 |
| Female | 0.659 | 0.813 | 0.898 | 0.984 | 1.131 | |
| 80-84 | Male | 0.796 | 0.965 | 1.060 | 1.172 | 1.333 |
| Female | 0.609 | 0.769 | 0.869 | 0.968 | 1.189 | |
| 85+ | Male | 0.754 | 0.917 | 1.037 | 1.162 | 1.322 |
| Female | 0.607 | 0.769 | 0.863 | 0.948 | 1.090 | |
What to expect by age group
Among US adults aged 30 to 34, the middle 50% measure 0.884 to 1.120 for men and 0.724 to 0.966 for women. The median rises from 0.894 for men and 0.793 for women at 20-24 to 1.142 for men at 65-69 and 0.932 for women at 60-64. A ratio above 1 means the trunk has a higher fat percentage than the legs.
| Age | Males | Females |
|---|---|---|
| 20-24 | 0.805 to 1.001 | 0.685 to 0.924 |
| 25-29 | 0.876 to 1.069 | 0.731 to 0.955 |
| 30-34 | 0.884 to 1.120 | 0.724 to 0.966 |
| 35-39 | 0.942 to 1.166 | 0.736 to 0.986 |
| 40-44 | 0.955 to 1.193 | 0.748 to 0.986 |
| 45-49 | 0.969 to 1.225 | 0.785 to 0.982 |
| 50-54 | 1.003 to 1.231 | 0.803 to 1.003 |
| 55-59 | 1.033 to 1.231 | 0.831 to 1.019 |
| 60-64 | 1.043 to 1.254 | 0.848 to 1.020 |
| 65-69 | 1.034 to 1.251 | 0.831 to 1.029 |
| 70-74 | 0.988 to 1.237 | 0.830 to 1.010 |
| 75-79 | 0.967 to 1.194 | 0.813 to 0.984 |
| 80-84 | 0.965 to 1.172 | 0.769 to 0.968 |
| 85+ | 0.917 to 1.162 | 0.769 to 0.948 |
Detailed Breakdowns
Select an age group and sex below for detailed percentile charts and distribution labels.
Frequently Asked Questions
How is the trunk-to-leg fat percent ratio calculated?
Divide the trunk's fat percentage by the fat percentage of both legs combined, using the regional results of a whole-body DXA scan. A trunk at 30% fat and legs at 30% fat give a ratio of 1.0.
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-limb fat mass ratio?
This ratio compares fat percentages, so it does not depend on how much tissue each region holds. The trunk-to-limb fat mass ratio compares fat masses in kilograms and includes the arms.
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.