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How to set targets for fat loss and muscle gain

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.