How to Read Your DEXA Scan: A Guide to Your Results

A DEXA scan report produces more numbers than most people expect. Body fat percentage is the one people came in for. The rest of the page — regional breakdowns, lean mass by limb, visceral fat area, T-scores, Z-scores, comparison charts — often gets skimmed or ignored.

That's where most of the actionable information lives.

This is a section-by-section breakdown of what a standard DEXA report contains, what each number actually means, and how to think about it in context of a training and nutrition plan.

Body fat percentage

What it is: The percentage of your total body mass that is fat tissue. Calculated by dividing total fat mass by total body mass.

What it tells you: Where you currently sit on the body composition spectrum relative to population norms. Most DEXA reports include a chart placing your result in a category (underfat, healthy, overfat, obese) based on age- and sex-specific reference ranges.

What to watch for: A single body fat percentage reading has limited standalone value. It is most useful as a baseline against which future scans are compared. The direction of change — and which tissue is changing — matters more than the absolute number.

The important nuance: Body fat percentage is a ratio. If lean mass increases and fat mass stays constant, body fat percentage drops without any fat loss occurring. Conversely, if you lose both fat and muscle simultaneously — a common outcome of aggressive caloric restriction without resistance training — body fat percentage may barely move even as total mass decreases. This is why the report sections on lean mass and fat mass separately are more informative than body fat percentage alone.

Regional fat distribution

What it is: Fat mass broken down by body region — typically arms, legs, trunk (android and gynoid zones), and total. Expressed both as absolute mass in grams or kilograms and as a percentage of each region's total tissue.

What it tells you: Where your fat is stored. Fat distribution pattern — particularly the ratio of trunk fat to limb fat — is independently associated with metabolic health risk beyond total body fat percentage.

Android vs. gynoid ratio: The android region covers the upper abdomen; the gynoid region covers the hips and thighs. An elevated android-to-gynoid ratio (more fat proportionally in the upper abdomen versus the lower body) is associated with higher metabolic disease risk. This ratio shifts with training, nutrition, and hormonal changes and is worth tracking across scans.

What to watch for: Disproportionate trunk fat relative to limb fat, particularly in the android zone. An individual with a low overall body fat percentage but high android-to-gynoid ratio may carry more metabolic risk than their total fat percentage suggests.

Visceral fat area

What it is: Fat stored inside the abdominal cavity, around the organs. Reported as an estimated area in square centimeters, sometimes alongside a visceral fat mass in grams.

What it tells you: This is the highest-priority number on the report from a long-term health perspective. Visceral fat is metabolically active — it secretes inflammatory compounds and disrupts hormone signaling in ways that subcutaneous fat (the fat under the skin) does not. It is the primary driver of the metabolic risk associated with abdominal obesity.

Reference thresholds: A visceral fat area below 100 cm² is generally considered low risk. The 100–160 cm² range is elevated. Above 160 cm² represents high metabolic risk. These thresholds are approximate and should be interpreted alongside other markers.

Why it matters beyond the number: Visceral fat responds to intervention. It is typically the first fat depot to decrease with improved nutrition, structured training, adequate sleep, and stress management. Tracking visceral fat across scans is one of the clearest ways to confirm whether those interventions are producing metabolic change — not just scale weight change.

Lean mass by limb

What it is: The fat-free tissue — primarily muscle, but also bone, connective tissue, and water — in each arm and each leg, reported separately. Expressed in kilograms.

What it tells you: Two things that most fitness tracking cannot provide: your absolute muscle baseline and whether significant left-to-right asymmetry exists.

Lean mass index: Some reports calculate lean mass index (lean mass divided by height squared), which allows your muscle mass to be compared against population norms in a height-adjusted way. This is a more meaningful comparison than absolute lean mass, which naturally varies with body size.

Left-to-right comparison: A small amount of asymmetry between dominant and non-dominant limbs is normal and expected. A difference of more than 0.5–1 kg between equivalent limbs — particularly in the legs — can indicate meaningful muscle imbalance, often from prior injury, movement compensation, or unilateral sport dominance. Catching and addressing imbalances is relevant both for injury risk and for optimizing training stimulus.

What to watch for across scans: Lean mass that is holding steady or increasing during a period of caloric restriction confirms that fat loss is occurring without significant muscle loss — one of the clearest indicators that a nutrition and training approach is working correctly. Lean mass that decreases alongside fat mass suggests the deficit is too aggressive or protein intake is insufficient.

Bone mineral density — T-score and Z-score

What it is: The density of bone mineral at specific sites — typically the lumbar spine and femoral neck. Reported as two scores:

• T-score: Compares your bone density to the peak bone density of a healthy young adult (peak bone mass reference population). The World Health Organization defines osteopenia as a T-score between -1.0 and -2.5, and osteoporosis as a T-score below -2.5.
• Z-score: Compares your bone density to age- and sex-matched peers. A Z-score below -2.0 is considered below the expected range for your age group.

What it tells you: Your current skeletal health status and how it compares to both peak bone mass norms and your age cohort. Bone density peaks in the late 20s and declines gradually thereafter, with the rate of decline accelerating in women during perimenopause and menopause.

Important context: The T-score thresholds (osteopenia, osteoporosis) were developed for clinical diagnosis of fracture risk and are most relevant for postmenopausal women and older adults. For younger individuals and those tracking bone health proactively, the Z-score — comparison to age-matched peers — is generally the more useful number. A Z-score in the normal range for your age indicates bone health is tracking appropriately for where you are in life, even if the T-score reflects that you haven't yet reached peak density.

One important clarification: DEXA scans at Custom Fit are body composition assessments. They provide bone density data as part of a comprehensive health picture and are not intended as medical diagnostic tools for osteoporosis or bone disease. For clinical management of bone density concerns, that conversation belongs with your physician, who may order a diagnostic DEXA separately.

Total mass and body weight

What it is: Your total scanned mass, broken down into fat mass, lean mass, and bone mineral content.

What it tells you: The composition of your body weight — not just how much you weigh, but what that weight consists of.

What to watch for: Scale weight alone tells you nothing about whether a change is favorable. Two pounds of weight loss that comes from muscle rather than fat is a worse outcome than two pounds of weight gain that is entirely lean mass. The DEXA report shows you what actually changed and in which direction.

How to use the results going forward

Establish the baseline first. Your first scan is a starting point, not a verdict. The most important thing it does is give you a baseline that future scans can be measured against with precision.

Set a retest interval that matches your goal. For active body composition change, three to four months gives enough time for meaningful shifts to accumulate while keeping the feedback loop tight enough to catch and correct a problem early. For general health monitoring without an active intervention, six months is a standard interval.

Read lean mass and visceral fat as your primary signals. Body fat percentage is a headline number. Visceral fat and lean mass by limb are where the actionable information lives. These are the metrics that most directly reflect whether your training and nutrition approach is producing the intended physiological outcome.

Bring the results into your training and nutrition sessions. A DEXA report reviewed in isolation is less useful than one reviewed alongside your coach or dietitian. The numbers become a plan when contextualized against your current program, your goals, and any other testing data you have.

At Custom Fit, every DEXA scan includes an immediate results review with a registered dietitian or exercise physiologist. For a complete physiological picture — body composition alongside cardiovascular fitness, metabolic blood markers, and genetic data — the Longevity Blueprint combines all four assessments into a single structured session.

Book a DEXA scan or learn more about the Longevity Blueprint.

DEXA scans at Custom Fit are body composition assessments performed by registered dietitians or certified exercise physiologists. They are not medical diagnostic tools for bone disease or osteoporosis.