Basal Metabolic Rate on Your InBody Result: How to Use the Number
The basal metabolic rate (BMR) on your InBody sheet is an estimate of the calories your body would use in a day at complete rest: breathing, circulation, keeping organs running. It is calculated from your fat-free mass, so more muscle gives a higher figure. It is not what you should eat. Your actual daily needs are higher, because they include everything you do on top of lying still. Use the BMR as a floor to understand, not a target to diet down to, and build your calorie estimate from there.
This post explains where the number comes from, how to turn it into a practical estimate, and the mistakes people make with it.
How the InBody calculates BMR
The scanner does not measure your metabolism directly. That would require a laboratory test of the oxygen you breathe in and carbon dioxide you breathe out. Instead, it uses a standard equation based on fat-free mass, which the machine estimates from the impedance scan.
The logic is sound: lean tissue, including muscle and organs, uses more energy at rest than fat does. Two people of the same weight can have quite different BMRs if one carries more muscle. Equations that use lean mass, rather than simply height, weight and age, tend to be more personal for that reason.
The limits come from the same chain. If the lean mass estimate is off because you scanned dehydrated or after a big meal, the BMR moves with it. Read our post on InBody accuracy for what shifts those readings.
BMR is not your daily calorie need
Your total daily energy expenditure has several parts:
| Component | What it covers |
|---|---|
| Basal metabolic rate | Staying alive at complete rest |
| Thermic effect of food | Energy used digesting what you eat, higher for protein |
| Everyday movement | Walking, stairs, standing, fidgeting, chores |
| Planned exercise | Training sessions, sport, runs |
For most people, BMR is the largest slice. But everyday movement is the most variable. A day of walking across London to meetings and a day at a desk followed by a sofa can differ by several hundred calories, even with the same workout.
Turning BMR into a working estimate
A simple, practical approach:
- Take the BMR from a scan done under good conditions.
- Multiply it by an activity factor. Commonly used factors run from about 1.2 for a largely sedentary day to about 1.5 to 1.7 for someone who is on their feet a lot and trains several times a week. Be honest; most desk workers who train three times a week sit around the lower-middle of that range.
- Treat the result as a starting estimate, not a fact.
- Track your intake and weight for two to three weeks, eating roughly at that estimate. Use a weekly average of morning weigh-ins, not single days.
- Adjust. If weight is stable, you have found your maintenance level. If it creeps up or down, adjust by a modest amount and review again.
Your real-world data will always beat any equation. The BMR simply gives you a sensible place to begin.
Using it for fat loss
For fat loss, the aim is a moderate deficit below maintenance, not below BMR. Eating far less than your BMR for long periods tends to backfire. Hunger rises, training quality drops, sleep can suffer, and you risk losing muscle as well as fat. Losing muscle then lowers your BMR, making the next stage harder.
A modest deficit, plenty of protein and regular strength training lets you lose fat while protecting lean tissue. The NHS suggests that losing weight at a steady rate of around 0.5kg to 1kg a week is a sensible target for most people. Our post on not losing weight in a calorie deficit covers the common mistakes when the maths seems not to work.
Using it for muscle gain
For building muscle, you generally need to eat at or slightly above maintenance, with enough protein. A rising BMR on later scans is a reasonable sign that lean mass is increasing, provided the scans were done in similar conditions. Expect small changes: muscle builds slowly, and so does the BMR estimate.
Common mistakes with the number
- Eating to the BMR. This is usually too little for an active adult.
- Comparing BMRs across machines. Different devices use different equations. Stick with one.
- Treating small changes as meaningful. A shift of a few dozen calories between scans is within normal variation.
- Ignoring movement. Daily steps often explain more of the difference between people than BMR does.
- Blaming a “slow metabolism”. True metabolic conditions exist, but most stalled progress comes from intake creeping up or activity dropping. If you suspect a medical cause, for example thyroid symptoms, see your GP.
Does metabolism slow with age?
Many people in their 40s and 50s notice that weight goes on more easily. Part of that is lifestyle: less incidental movement, more time at a desk, and the gradual loss of muscle that happens if you do not train for strength. Keeping or adding muscle is one of the few things that helps keep BMR up. Our post on metabolism after 40 goes into what is and is not known.
Safety and sense checks
If you are pregnant, have a heart condition or an implanted device such as a pacemaker, have diabetes, or have a history of disordered eating, check with your GP first before scanning or setting calorie targets. The InBody is not suitable for people with implanted electronic devices.
How we use BMR in sessions
In the private studio on Archway Road, the InBody is part of the kit, alongside the squat rack, dumbbells and cable station. When working with Artem, the BMR is read alongside your training, your schedule and how you actually eat, to set a starting calorie estimate that you then adjust with real data. It is a tool for conversation, not a prescription. See 1-1 personal training in Highgate for how sessions are set up.
Questions we get asked
Is the InBody BMR accurate?
It is a reasonable estimate because it uses lean mass. It is still an estimate, and your own intake and weight data will refine it.
Why did my BMR go down after losing weight?
Smaller bodies use less energy, and the scan may also show a drop in lean mass. Strength training and protein help limit that.
Should I eat my BMR plus my exercise calories?
Not exactly. Use BMR times an honest activity factor as a starting point and adjust with real results.
Can I raise my BMR?
Mainly by building muscle, which is slow. Moving more through the day has a quicker effect on total energy use.
For NHS guidance on losing weight steadily, see the NHS Better Health weight loss pages. For details on training in the studio, visit The Highgate House or the personal trainer page.
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