As a Muay Thai and strength and conditioning coach, you may expect that I’m focused on body weight goals for my clients. But I’m not. I really don’t care what you weigh.

Apart from making weight for a fight, scales aren’t a big player in my assessment of your progress. Too much is made of body weight, and it’s a liar. I constantly hear tales of daily fluctuations of weight on the scales, which in reality are just measurements of how hydrated you are.

If you want to watch my YouTube video of this entire post, click here >>

There Is No Cup

Half a litre of water weighs about 0.5 kg. So if you sweat 1-litre off during training, you’re a kilo lighter. If you drink a glass of water and that’s an instant ¼ kg added on — you’ve effectively become the container for that water. Dehydration is the fighter’s strategy for rapid, temporary weight loss in the final week before a fight. But this shouldn’t play any part in your general training goals.

So if body weight is such an unreliable indicator of progress, what am I interested in?

Power To Weight Ratio

Well I’m interested in your body composition. What’s your total lean mass and body fat percentage? This directly relates to not only your health, but also your athletic potential.

I basically want more muscle on you. Not body builder muscle, but functional running, jumping, punching and kicking muscle. I’m looking to improve your power to weight ratio.

A lower percentage body fat means less dead-weight, and more potential for speed and power. Only then I’m interested in what you weigh, and only with respect to which weight category you’re fighting in. Does the category suit you and your style? Is too much of your performance training time wasted affecting bodyweight rather than becoming a better fighting athlete?

Be Careful What You Wish For

Wanting to just drop weight is not specific enough, striving for that can hurt performance and health.

I could instantly drop your weight right now by 10 kg, by cutting off your leg, but your performance would definitely suffer! Ok, it’s a daft example, but you get the point…

Your goal needs to be more specific, you want to lose fat, not weight. And the scales can’t help you there. In fact, you can lose weight and still get fatter! It’s pretty easy to lose more muscle than fat during severe calorie restriction. If this happens, your body fat percentage increases, and your power to weight ratio slumps too. Don’t do this in preparation for a fight!!

It’s your muscle that burns calories,less muscle means fewer burned calories and an increased likelihood of overeating and inadvertent fat storage. As you lose muscle, you need fewer and fewer calories to maintain your dwindling body, and the easier it is to pack on the fat!

It’s Not A Fair Swap

Typically, fighters can lose between 0.5 – 1.0 kg of body fat every week without losing muscle (if using resistance training and getting enough protein to preserve lean mass). Whereas it typically takes about a month to put on just 0.25 kg of muscle! Muscle is hard earned and easily lost — keep your muscle at all cost.

Body Fat Percentage ChartSo generally, as a fighter I don’t care what you weigh, but I do care what your body composition is. The more of your weight that’s lean mass (and the less of it that is fat), the more punishment you’re capable of both dishing out and receiving.

I’m ideally looking for male fighters to be under 10% body fat and females under 17%. If you can reach these goals, then you’re giving yourself the best chance of being competitive in the ring. You’ll also be in true striking distance of your real fight weight once you factor in your pre-weigh-in dehydration strategies.

The Meat & Bones Of It

So if the weighing scales aren’t going to help you with this, what should you track? You must know how to measure body fat percentage to compare lean mass to fat mass.

You need to know that if you’ve lost weight that you’ve lost fat and not muscle, or if you’ve put on weight, it’s muscle not fat!

So here’s some methods of tracking body composition:

  1. Before & after photographs
  2. Measuring body dimensions with a tape measure
  3. Skin-fold Callipers
  4. Bioelectric Impedance Scales
  5. DEXA Scan

Most measurement methods are only good for establishing a trend rather than giving a definitive result, with the exception of a DEXA Scan – more on that in a moment.

Using these methods, you can tell over a longer-term if you’re losing of body fat and/or increasing in muscle mass but each method offers a varying degree of accuracy.

Make It Repeatable Or It’s Worthless

Now, ALL of the methods I just mentioned are useful if done with repeatable consistency. But, if you introduce too many variables then your measurements are useless. So let’s look at how to make good use of them.

Before & After Photos

Before & After Photos are great to give you a snapshot in time and truly offer up a side-by-side comparison of not only your physique but also your posture. For true a comparison, make sure you keep the lighting conditions and (lack of) clothing consistent.

Using a Tape Measure

tapemeasureIf you’re measuring body dimensions… get yourself an anthropometric tape. It’ll be much more accurate, and a hell of a lot easier to do by yourself!

Accurately describe your measurement sites so you can re-measure at exactly the same spot, or you’re wasting your time. For each site, generally re-measure a little higher and lower to find and record the largest dimension in that target region (neck, shoulders, upper arm, chest, waist, upper thigh, calf etc.)

Oh, and measure with your muscles relaxed, don’t hulk out! That will introduce another variable! Check each measurement two or three times to make sure it’s repeatable.

Skin Fold Callipers

Using skin-fold callipers requires a lot of practice to be anywhere near consistent, and even then, at best it’s only about +/- 9% accurate.

The other downside is you can’t do it to yourself! I personally don’t use this often, only occasionally to track abdominal fat. I don’t measure multiple sites and calculate body fat percentage — I simply record skin-fold thickness at particular ‘problem sites’ to gauge a fat loss trend.

Bioelectric Impedance Scales

Bioelectric Impedance scales are my preferred method of regular body composition tracking. It’s easy to do to yourself and if done reliably, is as accurate as having a skilled skin-fold measurement done for you!

Bioelectric impedance works by making an estimate of your body’s density by passing a low-level current through your body. Lean mass will conduct the current better, whereas fat mass is an insulator. It’s still a guess, so don’t take the measurement too seriously — just monitor if it’s trending up or down.

Here’s how to keep your measurements as repeatable as possible:

  1. Take measurements at the same time of day
  2. Take measurements with the same clothes on — or lack of clothes… fighters are used to parading around in their undies.
  3. Don’t eat or drink at least an hour before taking measurements
  4. Be consistent with your toilet habits before measurements!
  5. Don’t exercise just before hand — sweating affects the result
  6. Don’t vary whether you’ve had a bath/shower before hand (wet skin conducts better and heat will make you sweat)

My Top Tip is to Take your measurement first thing in the morning straight after waking, in minimal clothing, and after a trip to the toilet.


Ok, now onto the DEXA Scan. This is a REAL body composition measurement, the gold standard used by professional athletes everywhere. You’ll not only accurately determine what your percentage body fat is, but also exactly WHERE it is.

Some people have an apparent healthy level of subcutaneous fat (just under the skin), but have unhealthy levels of visceral fat (unseen fat around your internal organs). Visceral fat is what will kill you!

None of your fat can hide from a DEXA scan, you can accurately measure it all. These scans use medical-grade dual X-ray technology to provide a comprehensive report with regional muscle mass, fat mass and bone mass for arms, legs and trunk. So you can quickly see if you have a left to right muscular imbalance from all that training in a fighting stance!

The bone density report is another important factor for a fighter, lower density means your bones break easier. The good news is you should be ok; all that impact & loading from Muay Thai and strength training increases your bone density making you more resilient.

Here’s a video of bodybuilder running through the DEXA scan procedure in London, I’m sure you’ll find it interesting.

Many Athletes and sports teams are now regularly using this technology to track the effectiveness of their training programmes. And if like me, you’re lucky enough to live near a DEXA Scan facility, it’s definitely worth checking out at some stage, and comparing these accurate measurements to your regular bioelectric impedance results.

Think Lean Not Light

So as a fighter, I want you to think lean not light. However you measure body fat percentage, make it as accurate and consistent as you can or you’re wasting your time.

Your weighing scales are important come fight time, but the rest of the time you’re better off focusing on your body composition. This will lead to improved performance, rather than sabotage!

If you get your nutrition about right and put in the right kind of training combining technical Muay Thai, strength and conditioning sessions in your programme your body simply adapts to the demands you place on it and a lean, robustly muscled physique will naturally develop — form follows function.

I hope you’ve found this post useful, if you did, share it around, give me a comment, and please subscribe to my YouTube channel too.

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Don Heatrick

Founder of Heatrick Strength and Conditioning

Don Heatrick is a family man from the UK, former mechanical design engineer, European Muay Thai silver medallist, former pro Thai boxer (ranked 4th in UK while aged 40-years), a Muay Thai coach, podcast host, and the go-to expert on Muay Thai performance training with over 25 years of coaching experience.

Don helps ambitious fighters and coaches take their game to the next level by bridging the gap between Strength & Conditioning, Performance Science, and Muay Thai.

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