How often to measure body composition

How often should you do an InBody scan?

Every 4 to 8 weeks for most people. That matches InBody's India site, which recommends regular testing every 4 to 8 weeks under consistent conditions, and it fits the measurement evidence below.

If you are in the first weeks of a new plan you may want a baseline, then the next scan after a full training block. Scanning more often than that mostly measures how hydrated and rested you were that day.

Why not scan every week?

Because a scan has a noise floor. McLester and colleagues (2020) scanned 67 healthy adults twice, 24 to 72 hours apart, on three InBody models. The devices were reliable, and the minimum difference needed between two scans to exceed measurement error was 2.12 to 2.73 percentage points for body fat percentage, 1.49 to 2.39 kg for fat mass and 1.60 to 2.32 kg for fat free mass.

A real change smaller than that gap can hide inside the noise. That is our reasoning for leaving several weeks between scans, so that a change has time to grow larger than the gap. The same study found the InBody models underestimated body fat percentage against DXA, which is another reason to compare scan with scan on the same machine, not with a different method.

How do you prepare for an InBody scan?

InBody USA publishes a do and do not list for consistent conditions. In plain words:

Do

• Keep normal fluid intake the day before and hydrate one hour before the test.
• Stand upright for 5 to 10 minutes before the test.
• Test at the same time of day every time.
• Take off heavy accessories such as jewellery and watches.
• Allow 20 minutes for your body temperature to settle after hot or cold exposure.
• Use the restroom before the test.

Do not

• Exercise before the test. InBody says to test only after you have fully recovered, which it puts at 1 to 3 days.
• Eat before the test. Wait at least 3 hours after your last meal.
• Wear heavy clothing, accessories or jewellery.
• Have lotion or ointment on your hands or feet.
• Wear socks or pantyhose.

Can you scan after a workout, a sauna or an ice bath?

InBody's list says no to exercise beforehand and asks for 20 minutes after exposure to hot or cold temperatures. At UnReal that matters, because Floor 8 has a sauna and cold plunge at Reset Club and the gym floors are one lift ride away.

Our suggestion: scan first, then train and recover. If you scan on different days, do it at the same hour, before training, and note anything unusual such as a heavy night out or a long flight.

Why does hydration matter?

Because the scan infers your lean tissue from how current moves through body water. Kyle and colleagues (2004) wrote that BIA determines fat free mass and total body water in people without significant fluid and electrolyte abnormalities, and that its use in altered hydration states needs further research. So keep hydration as normal and as repeatable as you can.

What should you track between scans?

Three numbers, in this order:

1. Skeletal muscle mass, to see whether muscle is holding or rising.
2. Body fat mass in kilograms, because it does not hide behind a changing weight.
3. Body fat percentage, with the noise floor above in mind.

Add your waist measurement and a progress photo under the same light if you like. The InBody result sheet guide explains each line, and what a good InBody score is explains the summary number.

Sources

• InBody USA, InBody test preparation and technology (read 2026-10-06).
• InBody (inbody.in), InBody score explained, for the 4 to 8 week recommendation (read 2026-10-06).
• McLester CN and others. Reliability and agreement of various InBody body composition analyzers as compared to dual energy X ray absorptiometry in healthy men and women. Journal of Clinical Densitometry, 2020.
• Kyle UG and others. Bioelectrical impedance analysis, part I: review of principles and methods. Clinical Nutrition, 2004.

This page is general information, not medical advice.