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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!

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 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:

1.    Arms
2.    Legs
3.    Trunk
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.

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.

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!

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.