How to Read a Body Composition Report: A Coach's Guide to InBody, DEXA and Blood Tests

Sooner or later a client sends you a body composition printout from their gym, a DEXA scan from a clinic, or a blood report from their doctor, and asks: "Is this good?" The report has forty numbers on it. Maybe six of them should change how you coach.

This guide is about those six, how to compare reports without fooling yourself, and where your job stops.

The three kinds of report clients bring

• Bioimpedance scans (InBody and similar). Standing on a machine that passes a small current through the body. Quick, cheap, common in gyms — and sensitive to hydration and timing.
• DEXA scans. An X-ray based scan at a clinic. More precise for fat, lean mass and bone, and less affected by what someone drank that morning.
• Blood tests. Glucose, lipids, thyroid, vitamin D, B12, haemoglobin and so on, each with the lab's reference range printed next to it.

The numbers that matter for coaching

• Body fat percentage. More useful than weight or BMI for most clients, because it separates fat from everything else. Watch the trend, not one reading.
• Skeletal muscle mass (or lean mass). The number that tells you whether a fat-loss phase is costing muscle. If weight drops and muscle drops with it, look at protein and training volume.
• Visceral fat rating. Fat around the organs. A high rating is a good reason to prioritise fat loss and activity, and a good motivator for clients who don't care about the mirror.
• Basal metabolic rate (BMR). An estimate, not a measurement — a sensible starting point for calorie targets, then adjust from real weekly results.
• Waist measurement. Not glamorous, but cheap, repeatable, and closely tied to health risk. Measure it yourself between scans.
• Flagged blood markers. Anything the lab marks high or low. Your job is to notice, not diagnose.

What to mostly ignore

Segmental readings (left arm vs right leg), "body age", fitness scores and the machine's own target weight are rarely worth a conversation. They change with posture and hydration and they distract clients from the trend that matters.

How to compare two scans fairly

Most "I lost 2 kg of muscle in a month" panics are measurement noise. Bioimpedance especially shifts with water. To make two scans comparable:

1. Same machine, same time of day — ideally morning, before food.
2. No hard training in the previous 12 hours, normal water intake the day before.
3. At least four weeks apart. Shorter gaps mostly measure noise.
4. Read three or more scans as a trend. One scan is a snapshot; one change is a rumour.

Where your job stops

Coaches can and should use body composition to set targets and adjust plans. Blood reports are different: if something is flagged — high glucose, low haemoglobin, an odd thyroid value — the right move is to suggest the client discusses it with their doctor, not to change their diet around it on your own.

Keeping reports in one place (without the typing)

The other problem with reports is where they end up: a photo in WhatsApp, a PDF in someone's email. Six months later nobody can find the first scan to compare against.

In Trainzilla, a coach can upload a report PDF to the client's record and the numbers are extracted automatically: weight, body fat, lean and muscle mass, visceral fat, BMR, body water, bone mass, waist/hip/chest, and blood markers with their units and the lab's reference ranges. It only records values that are actually printed — it never fills in a guess — and when a report is hard to read, it's marked for the coach to review before it goes into the client's progress timeline.

One honest limitation: extraction needs a PDF with real text in it, which is what most machines and labs export. A photo or a scanned paper report isn't read yet.

The short version

Focus on body fat, muscle, visceral fat, waist and anything the lab flags. Compare scans taken the same way, at least a month apart, and read the trend. Refer anything medical to a doctor. And keep every report on the client's record, so the next conversation starts from data instead of a hunt through WhatsApp.

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