Body composition and bone
DEXA scan (body composition).
A whole-body scan that separates fat, lean mass, and bone with millimeter precision. The image behind every metabolic and longevity conversation.
By a local imaging partner · 10-minute whole-body scan
Why it matters
Body weight tells you almost nothing about how you are aging. Two people at the same weight can have completely different metabolic risk depending on where their tissue sits. A DEXA scan separates total mass into fat (visceral and subcutaneous), lean mass (muscle and organ), and bone, region by region. Visceral fat alone reshapes how I read the rest of your data. Bone density catches osteopenia years before a fracture forces the conversation.
Two specific numbers from a DEXA reshape how I write your Plan. Visceral adipose tissue (VAT) is the inflammatory fat surrounding your abdominal organs, and it drives cardiovascular and metabolic risk in a way that subcutaneous fat does not. Appendicular lean mass tells me whether you are losing muscle as you age, which is the single biggest reversible risk factor for everything that goes wrong in your seventies and eighties. BMI cannot see either one.
What I read for
Visceral fat as a percentage of total fat. Lean mass distribution across limbs: asymmetries that point to disuse or injury. Bone density T-scores at the hip and spine. The trajectory across scans, not any single number.
I read a DEXA as four separate questions, each of which writes a specific instruction into the Plan:
- Where is the fat? (VAT vs subcutaneous, android vs gynoid distribution)
- Is there enough muscle, and is it symmetric? (appendicular lean mass index, limb-by-limb comparison)
- Is the bone holding up? (T-score at lumbar spine, femoral neck, total hip)
- What is the trajectory? (the change since the last scan is more useful than any single snapshot)
What it measures
A DEXA scan reads three layers of body composition in one ten-minute lie-flat scan. It uses two low-dose X-ray beams to differentiate tissue density, which is why fat, lean tissue, and bone separate so cleanly in the report.
Body composition. Total fat and total lean mass with the headline number most patients chase: body fat percentage. The more useful read is visceral adipose tissue (VAT), the metabolically active fat around the abdominal organs that drives insulin resistance and cardiovascular risk. The android-to-gynoid ratio (trunk fat divided by hip and thigh fat) is a related cardiometabolic risk indicator that BMI cannot see.
Bone density. T-scores at the lumbar spine, femoral neck, and total hip, scored against a young-adult reference population. T-score above -1 is normal. -1 to -2.5 is osteopenia. Below -2.5 is osteoporosis. Bone density is the single biggest predictor of fragility-fracture risk, and the trajectory is more useful than the snapshot. We measure, we intervene, we recheck.
Regional analysis. Fat and lean mass broken out by trunk, arms, and legs separately. This catches the asymmetries that explain stalled training (one leg weaker than the other), recovery from injury, and the muscle loss patterns that show up first in the legs as people age. The appendicular lean mass index (limb lean mass corrected for height) is the longevity-relevant number.
See all 14 biomarkers
Body composition
- Total fat mass
- Total lean mass
- Body fat percentage
- Visceral adipose tissue (VAT)
- Android-to-gynoid fat ratio
- Appendicular lean mass index
Bone density
- Lumbar spine T-score and Z-score
- Femoral neck T-score and Z-score
- Total hip T-score
- Forearm density (when indicated)
Regional analysis
- Trunk fat mass
- Limb fat by segment
- Limb lean mass by segment
- Tissue asymmetry analysis
Who this is for
A DEXA is the right test when body composition, metabolic risk, or bone health is part of the conversation, or when a number like BMI is hiding what is actually happening in the body.
Common reasons I order it
- Body recomposition work: losing fat while keeping or building muscle
- Metabolic concerns where visceral fat is suspected (high triglycerides, insulin resistance, fatty liver)
- Performance athletes wanting an objective baseline for lean mass and asymmetry
- Longevity-focused patients tracking muscle preservation over decades
- Women approaching or in menopause, when bone density loss accelerates
- Men over 60, when bone density and lean mass loss become real risks
- Anyone with a family history of osteoporosis or hip fracture
It is also a one-and-done baseline read. You do not need to be symptomatic to learn something useful from a DEXA. Most patients learn one or two things they did not know about their own body that change how they train, eat, or supplement.
How collection works
- 1
We decide it is the right test.
A short conversation to confirm a DEXA answers your question. If body composition is the question, we book the scan and the timing for repeat measurements.
- 2
You schedule the scan.
[NEEDS YOUR INPUT: How patients book at the local imaging partner. Do you place the order through Healthie and they call to schedule? Direct walk-in? Note any required steps so the patient knows what to expect.] The scan itself takes about 10 minutes. Plan on 30 minutes total at the imaging center.
- 3
You lie flat for the scan.
You lie on a padded table while a scanner arm passes over your body using two low-dose X-ray beams. The total radiation exposure is roughly the same as a cross-country flight, far less than a chest X-ray. No fasting, no injections, no discomfort.
- 4
We read the results together.
Results come back within [NEEDS YOUR INPUT: typical turnaround, usually same-day at the imaging center, with the report to me within a few days]. We sit down with them and translate the numbers into specific instructions for your training, nutrition, and supplementation Plan.
How to prepare
Preparation is minimal because DEXA is a non-invasive imaging study. A few things make the scan more accurate.
Eat normally: no fasting required. Eat and drink as you normally would.
Wear loose clothing without metal: athletic clothes without zippers, snaps, or underwire bras. Metal interferes with the X-ray reading and will make you change into a gown.
Remove jewelry, watches, and metal piercings: before the scan. Belly piercings and underwire need to come off.
Hydrate normally, but not excessively: the day of the scan. Heavy hydration shifts the lean-mass reading slightly because water is counted as lean tissue.
Avoid heavy training the day of the scan: if you can. Recent intense exercise causes muscle swelling that reads as transiently higher lean mass.
Pregnancy: do not get a DEXA if you are or might be pregnant. The radiation dose is low but unnecessary during pregnancy. Tell the technician if there is any chance.
If you plan to do serial scans (which I recommend for body recomposition work), try to scan at the same time of day and in the same hydration state each time. The trajectory is more useful than the snapshot.
What you get
A full DEXA report with body composition, bone density, and regional analysis. A debrief with me where we translate the numbers into specific instructions for your Plan: training adjustments for asymmetries, nutrition targets to move VAT, lean mass benchmarks to hold or build, and the bone-health interventions that matter at your age and sex.
A repeat scan in 6 to 12 months tracks the change. The trajectory across scans is what tells us the Plan is working. Most patients see meaningful body-composition shifts within 12 to 16 weeks of structured work.
Questions
Yes. The dose from a whole-body DEXA is roughly the equivalent of a cross-country airline flight, and far less than a single chest X-ray. The benefit of the information far outweighs the exposure for any non-pregnant adult.
DEXA is the gold standard for body composition. Bod Pod and bioelectrical impedance scales (InBody, etc.) estimate body composition from indirect measurements. DEXA measures it directly using two X-ray beams and reads bone density at the same time. Neither of the others can do that.
Through the practice, no. I write the order and you schedule the scan directly with the imaging partner.
[NEEDS YOUR INPUT: Cash-pay rate at your local imaging partner, typically $100 to $250 depending on the facility. Confirm and adjust.]
[NEEDS YOUR INPUT: For bone density indications (osteoporosis screening, fragility-fracture history), DEXA is often covered. For body composition alone, it is usually cash-pay. Confirm and adjust.]
6 to 12 months for active body recomposition work. Annual is sufficient for bone-density monitoring after a baseline. Sooner if a specific intervention warrants confirmation.
How to order this
Part of the Precision Partnership baseline. Lab fee at vendor cost. I interpret the results into your written Plan.
From the writing