Biomarkers · Anthropometric

Fat-Free Mass

Higher values go with lower risk of death. Not measured in our NHANES panel. The curve is drawn from the published study (source below).

Fat-Free Mass and risk of death

Published curve higher than the NHANES fitNHANES fit higher

Risk of death relative to the curve's reference value, drawn from the published study (source below).

Published risk of death1.42×low versus high fat-free mass (study-specific categories) (95% CI 1.30–1.55) · Meta-analysis of 49 observational cohorts of community-dwelling adults (FFM by CT, DXA, BIA or anthropometry)

Fat-Free Mass by age and sex

Each bar runs from the 5th to the 95th percentile, the darker part from the 25th to the 75th, and the tick is the median. Not a reference range or a target.

The percentiles as a table

Each row is one sex and age band: the values below which 5%, 25%, 50%, 75% and 95% of people fall (kg), from the survey named in the row. Not a reference range or a target.
Sex	Age	5th	25th	Median	75th	95th	n	Cycle / source
All	20-39	35.4	44.4	54.2	64.4	77.5	1,504	NHANES 2005-2006
All	40-59	37.2	44.1	55.2	64.4	78.3	1,433	NHANES 2005-2006
All	60-69	34.6	42.7	50.7	61.4	74.4	647	NHANES 2005-2006
All	all	36.0	44.0	54.1	64.0	77.5	3,584	NHANES 2005-2006
Men	20-39	49.0	56.5	62.8	70.0	83.3	797	NHANES 2005-2006
Men	40-59	50.2	58.3	64.0	70.8	82.3	712	NHANES 2005-2006
Men	60-69	46.5	55.9	61.4	68.2	75.9	324	NHANES 2005-2006
Men	all	48.8	57.3	63.3	70.2	81.9	1,833	NHANES 2005-2006
Women	20-39	33.6	38.5	43.9	49.4	59.7	707	NHANES 2005-2006
Women	40-59	35.6	39.8	44.6	50.7	61.5	721	NHANES 2005-2006
Women	60-69	33.4	38.6	43.9	48.5	58.7	323	NHANES 2005-2006
Women	all	34.3	39.2	44.2	49.9	60.5	1,751	NHANES 2005-2006

What studies found when this marker was changed

They describe what happened in those study groups, not a recommendation. See all catalogued interventions.

Measured changes in Fat-Free Mass, study by study

4 effects with a numeric size, each from one study arm: the dot is the reported change, the line its 95% interval where one was given. Green points move the marker the way lower risk of death lies; amber the other way. Study results in the groups studied, not predictions for a person.

Each row is one study: what was changed, the effect it reported on this marker, and the source.
Type	Intervention	Reported effect	Evidence	Source
supplement	Dietary protein supplementation during >=6 weeks of resistance exercise training in healthy adults	Additional FFM gain of 0.30 kg (95% CI 0.09-0.52) during resistance training	meta-analysis	Morton RW, et al. Br J Sports Med. 2018. A systematic review, meta-analysis and…
supplement	Creatine monohydrate (~7 g or 0.3 g/kg/day) combined with resistance training in adults under 50	Lean body mass +1.14 kg (95% CI 0.69-1.59) vs resistance training alone; fat mass -0.73 kg	meta-analysis	Desai I, Wewege MA, Jones MD, et al. J Strength Cond Res. 2024.

Things that worsen it

Each row is one study: what was changed, the effect it reported on this marker, and the source.
Type	Condition or exposure	Reported effect	Evidence	Source
diet	Restricting eating to a 10-hour window daily for 8 weeks in college-age adults with overweight/obesity	Fat-free mass -2.3 kg with TRE alone over 8 weeks; +1.6 kg with resistance training; maintained with TRE+RT	RCT	Cui T, et al. J Int Soc Sports Nutr. 2025. Efficacy of time restricted eating…
pharmacologic	GLP-1 receptor agonist therapy in adults with diabetes and/or overweight/obesity (22 RCTs)	Lean mass -0.86 kg (95% CI -1.30 to -0.42), about 25% of total weight lost (-3.55 kg)	meta-analysis	Karakasis P, Patoulias D, Fragakis N, et al. Metabolism. 2025.

What else moves this marker

They describe those study groups, not an individual, and an association is not a cause.

Environmental and occupational exposures

Each row is one study: what it compared and the change it reported in this marker.
What	Effect on the marker	Comparison · population	Source
↑ Fetal cannabis exposure · any cannabinoid detected in maternal urine at ~27 weeks' gestation	+1.2 kg (95% CI 0.4 to 2)	exposed vs non-exposed offspring at mean age 4.7 years · 103 mother-child pairs from the Healthy Start cohort, Colorado; ~15% exposed	prospective cohort · PMID 35357471

Sources

Risk curve: Haas 2026 (PMID 42430205): all-cause RR 1.42 (1.3-1.55) low versus high fat-free mass (study-specific categories). Scaled to US values (NHANES).
Haas et al. Association Between Fat-Free Mass and Mortality: A Systematic Review and Meta-Analysis. Journal of cachexia, sarcopenia and muscle. 2026;17:e70331.

Map Fat-Free Mass against another biomarker.

Map Fat-Free Mass against another marker