A body composition scan generates a detailed report of your physical makeup. The numbers are only useful if you know how to read them. Most people glance at weight and body fat percentage, then file the report away. The scan actually tells a much richer story: metabolic health, muscle balance, visceral fat risk, and whether your current nutrition and training approach is working.

Body fat percentage

Body fat percentage is the proportion of your total body mass that is adipose tissue. Healthy ranges vary by sex and age. For men, 10 to 20% is healthy, with athletic ranges at 8 to 15%. For women, 18 to 28% is healthy, with athletic ranges at 15 to 22%.

Context matters more than the absolute number. 25% in a 25-year-old woman is different from 25% in a 55-year-old man. Your coach reads your number against your age, sex, goals, and health history.

Skeletal muscle mass

The total mass of muscle attached to your skeleton, measured in kilograms. It is the single most important metric for long-term metabolic health because muscle mass drives basal metabolic rate, improves insulin sensitivity, protects bone density, and is the strongest predictor of physical independence in later life.

Healthy skeletal muscle mass depends on frame size and sex. As a guideline, men should carry skeletal muscle mass at least 40% of total body weight, women at least 30%.

Visceral fat level

Visceral fat is the fat stored around your abdominal organs. Unlike subcutaneous fat (under the skin), visceral fat is metabolically active. It produces inflammatory cytokines and hormones that raise the risk of type 2 diabetes, cardiovascular disease, and certain cancers.

BIA scanners report visceral fat on a 1 to 20 scale. Levels of 1 to 9 are normal. 10 and above indicates elevated risk. The metric matters because someone with a normal BMI can carry dangerous levels of visceral fat, a pattern called "TOFI" (thin outside, fat inside).

Basal metabolic rate and total energy expenditure

Basal metabolic rate (BMR) is the number of calories your body burns at complete rest to maintain breathing, circulation, cell production, and temperature regulation. Total energy expenditure adds activity calories.

These numbers anchor nutrition planning. A declining BMR over time, beyond what weight loss alone would predict, can indicate metabolic adaptation that requires programme adjustments.

Segmental analysis

Advanced BIA scanners break down lean mass and fat mass by body segment: right arm, left arm, trunk, right leg, left leg. That reveals muscle imbalances between sides that may indicate injury compensation, trunk development relative to limbs, and whether training is producing balanced development.

Segmental data is useful for spotting asymmetries before they lead to injury.

Common misinterpretations

Weight gain does not always mean fat gain. Early in a training programme, increases in body weight often reflect muscle gain and water retention in muscle tissue. Body fat percentage fluctuates with hydration status. For reliable trends, scan under consistent conditions. BMI is close to useless for individuals with significant muscle mass. It cannot distinguish muscle from fat.

Frequently asked questions

My weight went up but my body fat went down. Is that good? Yes. That pattern indicates body recomposition, gaining muscle while losing fat. One of the best outcomes a nutrition and training programme can produce.

Why does my scan result vary between morning and evening? Hydration, food intake, and exercise all affect BIA readings. For consistent tracking, scan at the same time of day under similar conditions.

How quickly should body composition change? Realistic rates: 0.5 to 1.0 percentage points of body fat per month, and 0.5 to 1.0kg of muscle gain per month for beginners (less for experienced trainees). Changes beyond these rates may indicate unsustainable protocols.

Every coaching client gets regular BIA scans with expert interpretation. Start your journey and learn about why body weight is a terrible health measure.