Just before Christmas 2016 a Bodyscan client presented with the most dramatic change in body re-composition we have ever seen.
In just four months (from August to December), the client lost 11.5kg of fat and gained 6.4kg of muscle.
The numbers are impressive enough on their own, but are even more remarkable when you learn the client:
1. used no drugs, stimulants, supplements or shakes
2. was in a calorie deficit of about 500 calories a day
3. did zero cardio
4. is female
Prepare to forget everything you thought you knew about fat loss, muscle gain and bodybuilding when you read Joanna’s story. It starts with a Bodyscan DEXA scan that was “so mortifying, so shocking that it messed with my head and took me six months to recover from”.
Then in August last year, Joanna began a programme of Bayesian Bodybuilding. Click 'Read more' to continue.
We recommend most clients return for a follow-up scan three months (12-14 weeks) after their first to track their changing body composition.
It is quicker to lose fat than build muscle, so if fat-loss is your priority you should certainly look to return after 12 weeks and check you’re making sufficient progress.
If your re-scan results are good, it will give you reassurance that your training and nutrition programme is right for you and you can continue with more of the same.
Unfortunately for many, re-scan results are a disappointment. But knowledge is power, and you’ll now be able to make adjustments or stop and change course completely. Imagine waiting nine months or a year before you discovered you’ve been wasting all that time.
Typically, disappointment is due to high levels of muscle loss during a fat-loss phase (we regularly see people losing more muscle than fat) and, conversely, big increases in fat with little to show in terms of lean gains.
Uneven muscle gain where certain areas of the body progress faster than others is also common, as is not gaining any muscle at all. This can be due to a number of factors such as a too-low calorie intake (no muscle gain) or the incorrect training programme, intensity or rep range.
It is better to find out now that the desired changes in body composition are not occurring and do something about it.
Another reason for checking-in sooner is to be sure that the direction of travel has been consistent over the entire period. If you have more body fat in January than in the previous June, we’ll never know if it was just Christmas to blame or you wasted seven months doing the wrong thing. A re-scan in September would have provided some insight.
Finally, the constant refrain we hear from new clients is, “I wish I’d done this three months ago so I could see how things have changed.”
Only a DEXA body scan will give you the accurate, consistent, reproducible results that will enable you to optimise your progress.
If you’ve lost some momentum or are just not sure if you’re on the right track, booking a re-scan to see your results will be the motivation you need to kick start your body composition transformation.
We see many clients at Bodyscan who lose a lot of fat but who also lose a great deal of muscle too.
Sometimes so much that their body fat percentage actually goes up.
Look at the Bodyscan reports of these two clients who both did ‘biggest loser’-style diets with severely restricted calories: Nikhil, whose results are above, lost 4.7kg of muscle to his 4.9kg of fat, while Robert lost a whopping 10.8kg of muscle for 25.2kg of fat. Those big muscle losses do not bode well for keeping the fat off.
Indeed, loss of muscle is the reason why so many people who shed a lot of weight (see this article about DEXA and Oprah Winfrey) yo-yo back up again, and it highlights the importance of retaining your muscle mass when you embark on a fat loss regime.
Many people assume that when in a calorie deficit your body will turn first to its fat stores to make up the gap. But your body’s survival instinct takes an opposite view. Carrying muscle mass is calorie inefficient; big muscles burn a lot of calories even at rest. That’s why gaining muscle mass takes a lot of time, effort, heavy weights and loads of food.
Fat, on the other hand, is a great store of energy and helped ensure our ancestors’ survival when food was sparse and before there was convenience food within arm’s reach.
The need to survive and the expensive energy requirement of lean body mass is why your body quickly depletes your muscles - rather than your fat - when you reduce your calorie intake. The double whammy is that with lower muscle mass your body then burns fewer calories when at rest, so if you break your diet and simply go back to what you were eating before there’s now a bigger gap than there used to be between the calories you’re taking in and the calories you’re burning. Result - ballooning fat.
The statistics vary but a quick flick through a number of articles puts the number of people returning to their starting weight or above after a diet anywhere between two-thirds and 97%.
To retain your calorie-burning muscle, therefore, it’s a very good idea to add weight training to your programme. Unlike our big muscle-losers above, these two Bodyscan clients made resistance work a core part of their programmes: You can see from their Bodyscan reports that Katy reversed a fat gain/muscle loss to put on 3.2kg of muscle while losing 2.7kg of fat, and Rupert lost an incredible 14.3kg of fat while still building 2.2kg of muscle. The results speak for themselves.
In my experience as a personal trainer, success is wholly dependent on consistency. There is no point in any diet or exercise programme if you’re not going to stick to it, which is another reason why slashing calories and manic fitness schedules don’t work. In a couple of weeks you’ll be fed up and succumb to temptation. It's better to plan for slower, more gradual fat loss by restricting calories just 10% or 20% below maintenance levels and an achievable exercise and gym schedule. (Note: if you're gaining fat, you're already eating above your maintenance calories. Check out our body composition calculator for an idea of your calorie requirement.)
If your programme has derailed, it’s probably time to get a new Bodyscan baseline. We’ll give you achievable targets and then measure your progress in 3-4 months’ time.
Author - Archie Williams
This month (September 2016) we released the latest updated Bodyscan percentile tables, with data from over 2000 client scans - 1400 men and 650 women.
The new tables now includes regional fat mass, so you can see how typical your fat distribution is. You’ve been able to assess your muscle distribution with the previous tables, as described in this blog post about skipping leg day.
A ’typical’ fat distribution would expect to see fat mass for arms, legs and trunk in a straight horizontal line across the last three columns of the Regional Fat Percentiles table. The table is shown below.
The woman whose scan image appears at the top of this post might look to be carrying all the fat in her legs and trunk but when we plot her fat mass in the tables (shown in the report excerpt next to the image to be about 1.8kg in the arms, 10kg in the trunk and 5.9kg in the legs), we see that she actually carries proportionately most in the arms and least in the trunk.
Of course, you can’t spot-lose fat, but a change in the shape or angle of your plotted line through arms, trunk and leg fat mass will clearly show you how and where fat is shifting.
The data has changed little since March but the big sample size now gives us a very solid, reliable base against which to compare your individual results.
As well as showing fat and lean mass variations between the left and right sides of your body, Bodyscan can show you top-to-bottom variations too.
Using Bodyscan’s percentile tables, you can plot the lean mass in your arms, legs and trunk to spot discrepancies or weaknesses in your muscle distribution.
The most common variation we see is among gym-going men who commit that most heinous of crimes - skipping leg day. Take a look at this guy’s regional results and how they reveal workouts focused on arms and upper body.
The lean mass in his arms (the first two numbers) averages at around 5kg, in his trunk (the third number) at about 33kg, and about 10.8kg in each leg (the fourth and fifth numbers).
When we plot those quantities on our percentile tables (above), we see they equate to approximately these percentiles:
Arms (5kg) 95th percentile; Trunk (33kg) 77th percentile; Legs (10.8kg) 55th percentile.
That is, the lean mass and muscle in his legs is way behind that of his arms and trunk and, in absolute terms, just above average (the 55th percentile).
With a more even distribution we would expect similar percentiles across all regions of the body. To bring his legs into line with his arms, therefore, he needs to increase muscle mass in each leg from 10.8kg to about 13kg - a shortfall of more than 2kg in each leg.
So don't skip leg day!
On Tuesday 12th April, my first client of the day produced an incredible result.
In just four months Martin has lost 13.6kg (that’s over 2 stone) of pure fat. And he did it on a ketogenic diet, in which 70% of his calories come from fat, 25% from protein and almost none from carbs.
The fat loss would probably have been greater a month ago as recent family events forced Martin to diverge from the high-fat, ultra-low-carb regimen.
The highlights of his report are:
Martin’s results endorse the groundswell of opinion and evidence that it’s OK – in fact, highly beneficial – to eat plenty of naturally occurring fat and that carbohydrates are the underlying cause of obesity.
If you’re interested in Martin's information sources, he kindly points to:
We also found this very interesting 30-minute ‘Catalyst’ programme from ABC Australia, made in 2014.
Since November, Martin has consumed his high-fat diet in a time-restricted window (a version of intermittent fasting) between noon and 8pm, and also aimed to be in a calorie deficit of 30-50%. Some keto advice is that you don’t have to count calories because your hunger levels are very well regulated without carb-induced insulin spikes, but Martin says keeping a sharp eye on calories was crucial because of the high-energy value of high-fat foods – a few macadamia nuts can cause a calorie blowout.
In February, after five months of strict ‘keto’ (he began the keto journey last September), Martin moved to having a carb re-feed once or twice a week, usually the night before bodyweight circuit training (TRX, press-ups, squats and lunges). This ‘cyclical keto’ with heavy-duty carb-ups of between a few hours and two days is outlined in ‘The Best Ever Bodybuilding Diet?’. Martin’s carb content would rise to 50% in these periods.
His more than 5:1 ratio of fat-to-lean loss is excellent by any standard (especially considering the sheer amount of fat he shed) and one wonders if he would have maintained more or even all his lean mass with a lower calorie restriction and by increasing weights beyond body weight.
Martin’s lifestyle changes started last August, when he was 131.5kg (21 stone) and wore XXL shirts and 44-inch trousers. He quit smoking and sugar and began restricting carbs and calories. In September he followed the keto rules more closely and saw improved results. He then replaced breakfast with a ‘bulletproof’ coffee (coffee and coconut oil) before removing the calorie-rich oil to start the 16:8 intermittent fasting.
He’s now a medium, 32-inch waist and below 90kg for the first time since he was 12 years old. Inspiring stuff.
Martin’s says: “It's hard to start, like any diet, but the difficulty is in establishing new habits. The biggest one is losing the starch component of most of your meals – it's culturally ingrained.
“Once you're used to it, it's quite easy. Keto is challenging in that it's a binary proposition – like being pregnant, you're in a ketogenic state or you're not. So you can't cheat (except in very controlled circumstances with strategic carb re-feeds).
“Get enough salts when you start, watch your fibre intake and expect to take a few weeks for your body to adapt. Once it does there are many benefits. For me, fat loss obviously, but also the steady blood sugar, reduced hunger and mental clarity are great side benefits.”
We hope you find Martin's story interesting.
MAN v FAT published one of the very first reviews of Bodyscan when we opened in London in January 2015. Today, the 35,000+ member men's forum is the biggest online referrer of hits to the Bodyscan site after Google Search.
It makes perfect sense, then, for us to team up with MAN v FAT and offer a free DEXA body scan plus face-to-face consultation in our latest competition. We're kicking ourselves we didn't think of it earlier!
You don't have to be a bloke to win, so click this link to go to the MAN v FAT website and enter now. You can ratchet up your entries by getting your friends to enter too.
You'll get the most accurate and precise measurement of your body fat and lean mass, plus data about your visceral fat and bone density too. Plus we'll take you through your report in detail and help you set targets (in kilograms) for fat loss and muscle gain.
The Bodyscan website and, more importantly, the booking pages that ask for your personal information and credit card details are now SSL-secure.
That means all data passed between your browser and the booking engine web server are encrypted and remain private. You can see this marked by the HTTPS (rather than just HTTP) at the front of each page's URL in your web browser.
Due to some software restrictions, we've had to take the booking engine (made by Australian company Bookeo) out of Bodyscan's own website and host it on its native site. It's exactly the same engine and works in exactly the same way but is no longer embedded as a widget on the Bodyscan booking page.
The upshot is that when you book a Bodyscan DEXA body fat test you can be sure your personal and credit card details are completely safe.
If you've been to Bodyscan for a DEXA scan then you can use the Bodyscan body composition calculator to set targets for fat loss, muscle gain or both.
After entering the data (in kilograms, not grams - therefore your bone mass (BMC) will be between one and four kilograms) from your DEXA Bodyscan report on the first (RMR) page (which gives you two formulae's outputs for your resting calorie requirement), you can advance to the Body Composition Calculator, which allows you to set targets for fat and lean mass, using your fat mass index (FMI) and lean mass index (LMI).
To arrive at FMI and LMI targets, you'll want to use the Bodyscan percentile tables (latest update December 2017), which you can see on our Data Page and are also at the back of your printed explanatory notes (download notes here).
The tables in the explanatory notes are for clients of all ages and the numbers hold very well up to age 50. On our Data Page the tables have been split into age bands and you can view and download these too.
Using the 'All Ages' data, you can see from the blue (male) tables, that the median (50th percentile) score for male FMI is 5.79 and the median LMI is 19.3. The orange (female) tables show medians of 7.62 and 15.5 respectively. (These figures have been updated as of December 2017).
If you're already carrying more fat and/or less lean mass than the average Bodyscan client, you might want to use these median values as initial targets for FMI and LMI.
On the body comp calculator you can move the fat and lean slidebars until your FMI and LMI (on the left of the page) reach or come close to those targets. You'll then have (immediately above the slidebars) the absolute amounts, in kilograms, of fat and muscle you need to lose/gain. You'll also see your projected change in weight - which might even be zero.
If you're better than the Bodyscan client average, you can set your targets to be the top quartile or top 10%.
The FMI and LMI targets come with a caveat - the Bodyscan client data does not represent a random sample of the UK population; they are self-selecting Bodyscan clients and they contain a range of ethnicities. Nevertheless, they are a very good starting point to set a tangible, achieveable target.
The opening episode of Doctor in the House airs at 9pm on Thursday 19th November and follows Sandeep and his family after his Bodyscan DEXA scan reveals he has high levels of visceral fat.
We have no idea what the final edit will look like but we hope it will raise awareness of the benefits of DEXA fat testing. The BBC programme guide is here (click 'show more' for the full description).
One of the questions I get asked most often (by men) following a DEXA scan is: “what percentage body fat do I have to be before I see my abs?”
One of the commonest rule-of-thumb responses is ten percent. But like a lot of stuff to do with the body, it depends.
Look at this scan report for Dave, who has put on both fat and muscle in 12 weeks and now stands at 17.2% fat (subtotal). Moreover, he is 17.5% fat in the trunk and 20% in the belly (android) region. But the photos above show he has respectable (certainly noticeable) abs at the front despite being able to pinch at least an inch at the side.
Compare that to Peter, whose progress we have charted before and whose DEXA fat figures are just 13.7% (subtotal), 13.1% (trunk) and 16.1% (belly) and whose abs remain elusive (sorry, we didn't take a photo).
Dave says he’s just blessed with good, thick abs and works them hard by adding weights to exercises such as hanging leg lifts and incline crunches. He's not in the camp that believes abs don’t need their own workout; he will usually train them hard twice a week.
A quick look at the pair’s respective lean mass index (lean mass divided by height squared in the Lean Indices table on the first page of each report) shows up significant lean mass/muscle differences: 23.6 for Dave, 21.5 for Peter. That 2.1 is a big difference for an index where 19.5 is average and 25 is steroid territory.
Further, relying on body fat percentage doesn’t really make much sense because it’s just an average over your entire body. You might carry your fat atypically. And you can have a low percentage (or proportion) of fat but still be carrying a lot of it in terms of kilos. That's what your fat mass index will make clear.
So it seems that to see your abs you need one or more of: a low FMI, low percentage fat, high LMI, a good ab routine and genetic luck!
Between January and August (2015), more than 350 men and 150 women came for a DEXA scan at Bodyscan’s London location.
The aggregated results are available here and show something quite interesting. The median value for fat mass is almost identical - 16.8kg for men and 17.3kg for women.
Of course, women are typically lighter than men so 17kg of fat will equate to a higher body fat percentage for women. Indeed, the median weight and fat percentage for Bodyscan clients turned out to be:
Men: 83kg weight, 21.8% fat*
Women: 63.1kg, 30.1% fat*
It’s important to remember that Bodyscan clients are not a random sample of the UK population; they have elected to have a DEXA scan for whatever reason (fitness or fat loss) and are probably geographically close to London. The data also include a broad range of ages (the median age is 36 (men) and 35 (women)).
However the approximate 17kg for median fat mass for both sexes is, if nothing else, quirky!
*Note: The data points in the data tables should be all read independently of each other - one should not expect to be in the same percentile for all data points. That’s why the median figures above (21.8% of 83kg for men and 30.1% of 63.1kg for women) do not produce the median fat mass figures of 16.8kg and 17.3kg.
Returning to Bodyscan after 13 weeks, Lee, 46, has lost an incredible 8.5kg of body fat with NO loss in lean mass - in fact he’s GAINED over a kilo of muscle!
Download the main pages of Lee's Bodyscan report here.
He did it all by himself, following Mike Matthews’s Bigger, Leaner, Stronger programme, which has him lifting five days a week, hitting each major muscle group for about an hour each day plus some high-intensity interval training (HIIT) on the two rest days. His diet was 45% protein, 45% carbs and 10% fat, a customised meal plan provided by Matthews’s Muscle for Life website.
Lee’s Bodyscan DEXA report reveals he has lost fat pretty evenly. Before, his body fat percentage was higher than that of three-quarters of men his age. Now, he's turned the tables and moved from the bottom quarter to the top quarter!
The highlights of Lee’s journey so far are:
If you want to see what your own body fat percentage would be if you lost 8.5kg or how much fat you have to lose to meet a specific fat percentage target, take a look at our body composition and calorie requirement calculators.
To understand DEXA we need to understand a little about how X-rays work.
Traditional X-ray machines work by passing X-rays of a single energy through the patient’s body. The X-ray photons either pass through unaffected or they are ‘attenuated’ (absorbed or scattered) by the body.
The degree of attenuation (ie, how many photons pass through and how many are absorbed by the patient) depends on the thickness of the subject and, for a given thickness, on the density. Thicker and denser materials (like bones) attenuate X-rays more than thinner or less dense ones (like soft tissue).
For the simple identification of broken bones (when all that is needed is an image of the bone), single energy X-rays are all that is required.
To provide data about bone density, however, a problem arises because some of the X-ray attenuation is caused by the soft tissue surrounding the bone. An algorithm behind a single energy X-ray cannot be used to calculate the thickness of two unknown quantities (bone and soft tissue).
Fortunately, X-ray attenuation is also affected by the energy of the photon beam – the higher the energy, the lower the attenuation. By measuring attenuation based on both energy and subject thickness, the software algorithms behind dual-energy X-rays can use two simultaneous equations to calculate the thickness/density of both bone and soft tissue.
Further, since soft tissue is made up of fat and non-fat and if the density of fat is known (approximately 0.9 grams per cubic centimetre) then the mass of fat and fat-free (lean) tissue can be calculated, along with bone mass.
This essentially is the calculation behind DEXA (dual-energy X-ray absorptiometry) body composition measurement.
Accordingly, DEXA is referred to as a 3-compartment model, simply meaning that it measures the density of three components – bone, fat and fat-free soft tissue – to calculate their mass.
When I give a consultation, and in the explanatory notes that every Bodyscan client receives, I read fat and lean mass to the subtotal line in the DEXA report and ignore the head.
There are three reasons for that:
1. We’re really not interested in the head, face and brain when it comes to body composition.
2. DEXA makes some assumptions and estimates about brain fat and because the skull is an encased piece of bone.
3. If you’re tall we have to leave either your head or feet off the end of the table (and we’re much more interested in your feet!)
Bodyscan uses Hologic scanners in all it sites. The other chief manufacturer of DEXA body composition scanners, GE, does not include the head anywhere in the analysis.
It’s fair to say that omitting the head does create some inconsistencies in relation to other data on the report. For example, your fat mass index (fat mass/height-squared) and lean mass index (lean mass/height-squared) are calculated using the total figures. Also, your rate-of-change page that shows your progress in subsequent scan reports also plots changes in total numbers.
Of course, you can include the head and read the report that way, but for fat mass, lean mass and body fat percentage, we will read to the subtotal line and ignore the head.
On the front page of your Bodyscan report is a small table titled Lean Indices. There are two indices based on your lean mass here:
1. Lean mass/height-squared - Lean Mass Index (LMI)
2. Appendicular lean/height-squared – Appendicular Lean Mass Index (ALMI)
First of all, lean mass on your Bodyscan DEXA report means all lean tissue, or all soft tissue that’s not fat. Thus it includes internal organs but does not include bone. (Lean+BMC is lean plus bone, ie everything that’s not fat.)
Whilst your lean indices are not just about muscle, they give us a good indication about muscle mass and how it’s distributed.
Your LMI relates to all the lean tissue in your whole body, while your ALMI is just about the lean in your limbs (your arms and legs).
A simple way to make sense of how high or low your lean indices are is to check your percentiles in the ‘AM’ column to see how you compare to a population of the same age and sex. An AM percentile above 50 means that you have a higher lean index than most people your age and sex. A bodybuilder will typically have AM percentiles in the 90s (ie, an indication of more lean mass than just about everyone his/her age).
If the AM percentiles for LMI and ALMI are close together then it suggests that lean mass (and therefore muscle mass) is evenly distributed around the body. If they’re far apart (eg, an AM percentile of 50 for LMI, and an AM percentile of 75 for ALMI), this suggest that the muscles in the trunk are less well developed than in the arms and legs. It’s like scoring 75% in a French (limbs) exam but only 50% in a French & German (limbs + trunk) exam. Clearly, your German (trunk) is dragging you down. So go and work on that German trunk!
On your Bodyscan DEXA report there more numbers you don’t have control over than those you do.
When it comes to fat, these are the Total and Subtotal results for
1. Fat mass
2. Fat percentage
3. AM percentile
4. YN percentile
5. Fat mass index (fat mass/height^2)
6. Estimated visceral fat (mass, volume & area)
You don’t have any control over the fat numbers for:
4. Android region
5. Gynoid region
6. Android/Gynoid ratio
7. %Fat trunk/%Fat legs
8. Trunk/limb fat mass ratio
The reason is that you cannot spot-lose fat; you can’t control where it's stored and where it comes off. To lose fat in your legs or to change you’re A/G ratio you just have to lose fat. Period. Your body will decide where it melts away and where it sticks around.
Lean mass (muscle) is a different story. You can of course target muscle groups in your arms, legs and trunk to make specific gains in these areas.
Bone density is something you can increase by doing weights and resistance training and with a good diet that includes calcium. I have seen a number of young male clients recently with low full-body bone density Z-scores. All of them said they did not like milk. Go figure. One of them was a guy in his mid-30s who’s full-body Z-score was minus three (-3.0). That is the lowest I have seen and lower than most 90-year-old women. And he knew it from a DEXA scan two years previously.
We’ve recently introduced two new packages designed for those serious about improving their body composition and regularly tracking fat loss and muscle gain over the course of a year.
The two new V4 and V5 packages contain, respectively, four and five scans designed to be taken every 3-4 months over the course of a year as follows:
V4 example 1: January, April, July, October
V4 example 2: January, May, September, January
V5 example: January, April, July, October, January
Measuring your body composition regularly will keep you on track and ensure you’re not losing any hard-won gains.
The first scan in each package comes with a consultation and are valid for a year. Thus, do not buy these packages if you plan to get scanned less frequently than every 12-16 weeks.
You make great savings compared to buying the scans separately and can pay monthly to spread the cost as follows:
V4 package: £399 (save £177)
Easypay price: £39 per month for 12 months (total £468, save £108)
Click here to set up your direct debit for a V4 package
V5 package: £499 (save £216)
Easypay price: £49 per month for 12 months (total £588, save £127)
Click here to set up your direct debit for a V5 package
The V4 and V5 packages are available in London and Manchester but not Bury St Edmund’s.
I meet many Bodyscan clients who tell me they want to lose weight or they need to get down to a certain weight or that their ‘ideal weight’ is such-and-such.
It’s usually at this point that I deliver a little lecture, whose tone varies between politely mild to … shall we say … passionate!
Let’s be clear about this: unless you’re a boxer or a jockey or compete in a sport that requires you to be a particular weight, NOBODY NEEDS TO LOSE WEIGHT!
On the other hand, almost everybody needs to lose fat. As I wrote in a recent advertorial for Guardian newspaper supplement Obese Britain, the UK obesity crisis that costs the NHS alone more than £5 billion a year has got nothing to do with people being too heavy. It’s because people are too fat.
I had one client recently who, despite being a crossfitter for five years or more, kept saying he needed to get his weight down.
“Rubbish,” I said. “If you lost 2kg of fat and put on 3kg of muscle, would that be a good result for you?”
“Of course,” he replied.
“But you’d be a kilo heavier than you are now. You’re weight would go up.”
I could see the cogs inside his brain turning slowly as he began to realise the earth wasn’t flat any more.
Your weight is your relationship with gravity and that’s about it. As for BMI (body mass index), don’t get me started!
Almost everybody who comes for a DEXA body fat scan wants to know their body fat percentage. In fact, I would say that is far and away the one single figure they want to know.
But percentage body fat, while a valid measure and data point to have, is not necessarily the best – and certainly not the only - measure of fat.
Why? Because body fat percentage is simply a comparison of fat to non-fat. In isolation it doesn’t give any indication of HOW MUCH fat you’ve got, only the proportion that is fat COMPARED TO EVERYTHING ELSE.
A better number, or one to use in conjunction with your fat percentage, is your fat mass index (FMI), which is your total fat mass divided by your height squared.
The strength of your fat mass index is that it is based purely on the absolute amount of fat in your body. If your FMI goes down, it means you have definitely lost body fat. And, conversely, if you lose fat your FMI will definitely fall. It’s a two-way relationship.
You can’t say that about your body fat percentage. You could lose fat and your body fat percentage could stay the same or actually go up. How? If you lose more muscle than fat, that’s how (as has happened with one unfortunate client).
Your fat mass index, however, is related purely to fat mass AND it is independent of muscle mass. If you stack on a few kilos of muscle but your body fat remains unchanged, your FMI will stay the same. It only moves if the amount of fat you carry changes.
Take a look at this real life Bodyscan bodybuilding client. His body fat percentage (subtotal, without the head) is 15.1% and his age-matched percentile is 3. That means only 3% of men his age have a lower body fat percentage. That great number is achieved because so much of him is muscle (ie, the proportion of his fat to everything else is very small).
But his fat mass index, at 5.13, achieves an age-matched percentile of only 25, ie a quarter of men his age have a lower FMI.
Why? Because FMI takes into account the actual amount (mass) of fat he’s carrying. And when we take into account his height, that fat mass is not quite as amazing as his percentage body fat.
So don’t obsess about your body fat percentage. Read it in the context of other fat and lean mass indicators.
[email protected] | phone 020 3490 4171 | Company no: 08807421