Jul 01, 2021 / by Jon Bellis / No Comments

At our personal training studio in Northampton, we have a fancy machine that measures your body composition. Why do we have a sophisticated machine? Because we specialise in body composition change. We need to measure it so we know we are helping our clients to realise the best body composition possible.

Body composition machine.

Of course, we market ourselves as weight loss specialists because that’s what everyone understands. But we would be doing a terrible job if weight was our only focus. Weight has many components such as muscle, fat, water and bone. If you want to know how your weight is distributed in terms of those components, you have to dig a little deeper.

As a client progresses through their programme, we measure the components of their weight every month. We need to be sure that their programme, and their adherence to the programme, is exactly right.

But what should be your body composition? How can you interpret the readings you get when you break down the components of your weight? In this post, we take you on a brief tour of body composition change and its interpretation.


Our body composition machine

Here’s a printout from our machine that I produced this morning. I’ll talk you through it.

Body composition readout. This printout even tracks your body composition change.


Body composition analysis

In the top left, you’ll see the weight broken down into water, proteins, minerals and fat. These are the components I listed in the introduction, with two differences.

First, proteins are a proxy for muscle. It’s not entirely muscle because it includes proteins in your organs and other tissues, but the most significant component of the proteins number is muscle protein. Second, minerals are a proxy for bone mass. Again, there are minerals in other tissues and within your body water, but a significant component of the minerals number is bone mass.

Note that the proteins number is not the same as your muscle mass. Your muscle mass includes the water component stored in skeletal muscle, which is not captured in the proteins figure.

Also, note that the sum of body water, proteins and minerals is referred to as fat-free mass (FFM).


Muscle, fat and obesity analysis

Heading down the page from body composition, you’ll see a section with horizontal bars that go across the charts. There’s a grey section in the middle for each measure, which is regarded as ‘normal’. For some of these measurements, you might also choose the word ‘healthy’. Fat mass and percentage body fat (PBF) are examples.

Another is Body Mass Index (BMI), a standard measure of fatness or obesity where a BMI above 25 is regarded as overweight and moderately unhealthy. A BMI over 30 is considered to be obese. I am officially overweight, not because I carry excess fat, but because I have a lot of muscle. In this instance, I am not moderately unhealthy. This is an example of where you need to drill down into the figures to understand reality.


Low, normal and high figures

For all the measures, if you just have a black bar on the left and you’re not even lighting up the grey section, that figure is regarded as low. You’ll see this in my percentage body fat (PBF). The normal range is considered to be 15-20%.

If you are lighting up the grey and don’t have a black bar on the right, the figure is normal and healthy.

If you have a black bar on the right, the figure is too high. Two-thirds of the adult population, were they to get onto our machine, would have a black bar on the right for ‘Fat mass’.


The holy grail of body composition change

Our aim for all weight loss clients is to reduce the black bar on the right for fat mass and maintain the bar for skeletal muscle mass (SMM). If we can make the SMM bar move to the right, then even better. That’s the holy grail of body composition change; less fat, more muscle. Be aware, though, that it’s very difficult to achieve. We’ve helped several clients achieve this, but don’t let anyone tell you it’s easy. There’s no magic and no substitute for hard work.


Other measures

The other figures not mentioned so far are waist to hip ratio (WHR), visceral fat level (VFL) and visceral fat area (VFA). We will correlate WHR with our tape measurements of the waist and hips, and we can sometimes link VFA with the client’s girth around the middle.


Segmental lean and fat analysis

This gives us a distribution of muscle and fat. We use the muscle distribution mainly to check for imbalances. You’ll see that I am very slightly imbalanced, but not enough to tick the ‘Imbalanced’ box over on the right under ‘Body Balance Assessment’.


Body composition change

This charts your progress on three key metrics. You’ll see that I have been working hard over the past six weeks to reverse the decline I experienced due to my arthritis and subsequent operation. It’s amazing what you can do when your hips work properly!

For client check-in reports, we track numerous measures, not just these three and many that are not part of body composition analysis.


Comprehensive evaluation

Over on the right at the top, several figures are very useful. Here I talk you through a selection.


Body Type

If you plot BMI versus PBF, you can blocks that include categories such as muscular, fit, standard, overweight, obesity class 1, obesity class 2 and skinny fat. It’s great to see clients traverse the grid into better categories.


Biological age

There is a secret algorithm that calculates this based on the other data. But, having worked with this machine for several years, I can tell you that it responds almost entirely to muscle mass and fat mass. You will be older if you have more fat and less muscle. You will be younger if you have more muscle and less fat.

That confirms our constant assertion that having muscle is healthy and having excess fat is unhealthy.

The range goes from -5 to +5. You’ll see that my biological age is five years younger than my actual age. That’s because I have a lot of muscle and very little fat. And even though my percentage body fat is below normal, I am not being ‘scored down’ for that


Visceral fat mass

Visceral fat is the stuff around your central organs – your liver, pancreas and kidneys, for example. This is an important number for us and one that all our clients are keen to reduce.

Schematic of visceral and subcutaneous fat.

We train our clients in a way that maximises the reduction in visceral fat mass. We aim to get clients below 2 kg.


Body balance assessment

Our primary tool for assessing imbalances is the postural assessment and movement screen we perform with every client. It’s helpful to cross-check our observations with these two measures of body composition imbalance.


Control guide

This is an extremely useful section that helps us advise clients without plugging a bunch of numbers into a calculator. It provides targets that would take a client to the middle of ‘normal’, in other words, into the middle of the grey section on the bar charts.

If you’re to the right of normal on muscle, then the value will be zero – you have enough. Most clients start with enough, and it’s the fat they need to lose. Occasionally we’ll see someone with too little muscle and too much fat. They are closer to ‘skinny fat’ than most. Then the task is not simply to retain muscle but to increase their muscle whilst also reducing their fat. It’s that holy grail again!


Segmental lean mass

This gives us a more detailed numerical breakdown of lean mass.



How can you change your body composition?

If it were easy, everyone would be doing it, and we wouldn’t have a business. Everyone is different. Each person has a distinct starting point, different motivations, unique physiology and varying capabilities. A one-size-fits-all approach is a recipe for disappointment. That’s why every personal training programme is entirely bespoke.

Now, that said, there are rules of thumb that you can apply to almost everyone.  Below are the main factors for achieving favourable changes in body composition.


Changes in muscle

Having muscle is healthy. It helps you stay active, minimises the risk of injury or falls, helps you maintain good posture, helps fight obesity and makes you more resilient to illness. We all lose muscle as we get older, but you can slow that muscle loss right down by taking appropriate steps.



Muscle is destroyed by muscle protein breakdown (MPB) and created by muscle protein synthesis (MPS). These two processes ebb and flow during the day, depending on what you’re doing or have done. The aim is to minimise MPB and maximise MPS.

A collection of healthy carbohydrate. Carbohydrate is important for optimal body composition change.

If you want to favour MPS over MPB, you should

  • Get a healthy, balanced diet with lots of healthy nutrients, a relatively low % of fat, moderate protein and the rest in healthy carbohydrate.
  • Avoid long periods without food.
  • Train with weights as intensely as possible
  • Eat moderate amounts of high-quality protein regularly.
  • Avoid a low carb diet.
  • Avoid a high-fat diet.
  • Sleep well, getting 7 to 8 hours a night.
  • Avoid alcohol, stress and excess caffeine.
  • Create a calorie surplus for best results, or at least avoid a large extended calorie deficit.

Woman despairingly staring at small plate of food.


Changes in fat

I’m pleased that fat-shaming is scorned these days because it’s incredibly challenging to maintain healthy body fat levels with today’s food choices and lifestyles. There is a collection of different genes that favour fat accumulation and, if you have a lot of them, you’re going to find it harder to keep your fat levels down. So, in saying that everyone should aim to get their fat levels into the healthy range, we’re talking only about health. Having excess fat is unhealthy. Countless scientific papers have shown that being overweight or obese increases the risk of many diseases. Obesity is now a leading cause of death in the western world.


Fat reduction

Fat is either visceral or subcutaneous. Visceral fat is more closely associated with disease, and subcutaneous fat a good predictor of your overall shape and dimensions. You can’t target one over the other; they tend to reduce together. But you can emphasise visceral fat reduction with the right training.

Here are a collection of things you can do to reduce body fat

  • Create a calorie deficit.
  • Train hard with regular high-intensity exercise that includes some weight training.
  • Perform moderate-intensity cardio.
  • Be consistent and exercise daily.
  • Get a healthy, balanced diet with lots of healthy nutrients.
  • Avoid excess fat intake.
  • Sleep well, getting 7 to 8 hours a night.
  • Minimise alcohol intake.

Shadowy man drinking whisky. Excess alcohol will ruin your body composition change efforts.


Changes in bone

It’s crucial to maintain your bone mass to avoid osteoporosis and potential breaks as you get older.

Here are some things you can do to maintain your bone

  • Perform regular weight-bearing exercise.
  • Perform weight training.
  • Make sure there is plenty of calcium in your diet
  • Ensure you do not become vitamin D deficient, especially in the winter
  • Avoid excess caffeine or salt


Changes in water

Water isn’t a body composition parameter that we track to assess body composition change. But water changes can cloud the picture, so it’s helpful to understand them.


Long-term changes in water

You have two water compartments at a basic level: Intracellular water (ICW) and extracellular water (ECW). A lot of intracellular water is in your muscles. If you lose muscle tissue, your ICW and overall water numbers will change. So we expect water to change over time as muscle is gained or lost. This is better observed over a period of time.


Short-term changes in water

There are also short term changes in water that add considerable ‘noise’ to the readings of muscle and fat — the noise matters. For example, if a client arrives a lot more hydrated than last time, they will show as having more muscle than the previous time, even if they have not gained any muscle protein. That’s why we ask clients to prepare for each check-in in the same way and check-in at the same time of day for each visit. Even so, occasionally, it takes a skilled eye and experience to interpret the figures.

Water is also important for you if all you measure is weight. Water can fluctuate wildly. You may find you are one or even two kg heavier one day than the next. It’s not fat accumulation; it’s water changes. You may even see this phenomenon week to week. In particular, pre-menopausal women may experience cyclical variations in their water and weight.

What affects your water status? Here are some common influences:

  • Salt intake
  • Carbohydrate intake
  • Dehydration and subsequent rehydration
  • Hormones
  • The weather
  • Sweating
  • Fibre intake

So, you can see that there are many influences. Your water and weight can fluctuate from day to day or week to week. That’s why occasionally weighing at discrete moments in time can be misleading. Weighing regularly and charting the numbers is the best way to see what’s really going on.



As personal trainers, it’s our duty to help our clients get the best body composition possible. But I hope you can see that body composition is a more complex topic than many imagine. And, what’s more, influencing body composition is a multi-faceted undertaking unique to each individual. You do have to know what you’re doing, and you have to look at the data for each person if you are going to help them get the best results.

At our personal training studio in Northampton, we have everything we need to achieve our clients’ optimal body composition changes. We have the machine, the training equipment, the nutrition course for clients, the charting and technical tools and, of course, the know-how and experience.

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