My DXA body scan dexa weight loss body fat-min

My DXA body scan

Last week I wrote about my weight loss struggles, and my first appointments with a naturopath and functional doctor…

Exactly how overweight am I?

As I spoke about in my first post, my weight has not budged within a 3kg range since 2010, despite following a paleo diet and exercising regularly. Everyone always tells you that muscle weighs more than fat, but does it really? Does this apply to me?

I’ve been going to the gym regularly for the last few years, and for the last year or so I’ve been doing CrossFit. My arms have distinct muscle in them that I swear didn’t used to be there, and I am making good progress on increasing the weight I can lift – so that would suggest I have more muscle than I used to. So if I do have more muscle, and it weighs more, how can my total weight still be EXACTLY THE SAME?

The naturopath had suggested I go and have a DXA (Dual-energy X-ray absorptiometry; formally called a DEXA scan) body scan performed so I could see exactly what my body composition is. I was initially quite wary about the radiation, but apparently it’s the same dose of radiation as a short flight between Sydney and Melbourne. I take domestic flights often, this is important, so I figured it was worth it.

My DXA body scan dexa weight loss body fat-min

The DXA scan

Have you had one of these body scans? It’s completely open (I was expecting it to be enclosed, like an MRI scan) and not unlike being photocopied (I’d imagine). You lie on the DXA machine and it whizzes over you for about ten minutes whilst you watch an image of your body appear on the screen on the ceiling. I found it really confronting. Your fat mass is displayed in yellow. Lying flat on your back, no tailoring can disguise the yellow fat shown in the image.

I’m not ready to post my scan images just yet – it was enough to convince myself just to write about my weight loss struggle, let me tell you! The images in this post show some example DXA scans I found online. When I go back for my follow up scan in a few months, I will post both scans, side by side to show the difference and all of the statistics that go with it.

The image shows your bone in blue and your lean body mass (i.e. muscle & vital organs) in red. What amazed me was my skeleton. It is small – the “I’m just big boned” excuse can be completely dismissed. And how much would you expect your skeleton to weigh? Well mine is just over 2.2 kilos. Incredible. These DXA scans are also used to look at bone density, so I was pleased to see my bone mineral density is excellent (note to all those who’ve been told paleo doesn’t give your body enough calcium!). I also had slight variances between my left and right side, with my right side weighing fractionally more. Interesting – I wonder if many people have exactly the same on both sides?

In terms of muscle mass, the physiologist who conducted my DXA scan, and talked me through the results was surprised by how much muscle mass I have. He seemed to think I have about 10kg more muscle than an “average” woman of my weight and height would have. This was great to hear – and also surely must mean that I have in fact lost fat – it must just be a coincidence that my total weight number has not changed…

Unsurprisingly, my fat mass was too high – but only about 6% above a healthy range (I expected it to be a lot worse than this). The DXA scan clearly showed what I already knew, I store my fat around my hips (a typical pear shape). The danger zone is storing fat around your middle (the “central abdominal zone”, so I’m glad that’s one risk factor I don’t have. My estimate had been that I needed to lose about 15kg of fat, but the actual measurements, suggest I may “only” need to lose 11.9kg. It’s still a lot, but thanks to the bonus lean muscle mass, less than I expected.

Metabolism

The scan also calculated my Resting Metabolic Rate, which has opened up a whole new avenue on my journey of discovery…. metabolism, it turns out, is absolutely crucial in weight loss.

The DXA scan measured my resting metabolic rate as 1639 kcal a day. That means just to exist with absolutely no physical activity, my body needs 1639 calories a day…

I’m going to talk a lot more about metabolism in my next weight loss post – and share with you what I’ve found out – and what it means.

Before then, please share your experiences below. Have you had a DXA body scan? What did you find out?

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10 replies
  1. Margaret
    Margaret says:

    This is a new one on me, I have not heard of these scans. As far as I am concerned you are so brave, I don’t know if I could do this. Though I do admire your determination.

    I have a lot more weight to lose than you.
    I’ll follow your progress with interest.

    Reply
  2. Lorinda
    Lorinda says:

    I recently found your blog and just wanted to say hi, and I love reading your posts and recipes! I have toyed with getting a DEXA scan but it is not cheap and I was thinking that if the results are less than ideal, what would I (or could I) do differently. I was also interested in finding out my bone density given I don’t eat much dairy at all. Your post has inspired me to perhaps finally go and get scanned. Can you recommend any particular places in Sydney?

    Reply
    • Suz
      Suz says:

      I went to MeasureUp in the CBD. I definitely think it’s worthwhile. Interested to hear how you get on. I think those leafy greens stand us in good stead for bone density!

      Reply
        • Suz
          Suz says:

          I had two options – a quick scan for $85 or $150 for the scan plus consultation. As I’ve been seeing a naturopath, functional doctor – and didn’t want to hear their conventional wisdom advice, I found the $85 gave me more than enough.

          Reply
          • Gita Mathias
            Gita Mathias says:

            Hi Suz
            I live in Sydney and am subscribed to your newsletters.
            Can you please share the names of your Naturopath and FM doctor as I’m struggling with weight gain too inspire of being Paleo for the last 2 years.
            Thanks
            Gita

          • Suz
            Suz says:

            Hi Gita, unfortunately mine isn’t taking new clients, but there are a few sites that list holistic functional medical practitioners in Australia and I believe there are a few in Sydney and NSW.

  3. Katy
    Katy says:

    I’ve had several. They can be shocking because the media talks about BF% in a totally unrealistic manner. As well, personal trainers and gyms do caliper testing which is also highly inaccurate. For example, I did the DXA and then my gym started a whole30 and they did caliper testing. The calipers said I had 10% LESS BF than the DXA. So everyone is running around with this idea that we are all supposed to be close to 20% BF which for the average woman, is ridiculous.

    There was a study that showed women who have had at least one child have the lowest mortality rate at 28-30% BF. Most women are not naturally meant to be lean.

    I did one before I started crossfit and one 6 months after. I was frustrated as I had only lost 3lbs. The results: I had lost 10lbs of fat and gained 7lbs of muscle. Which explained why I had dropped almost tw dress sizes.

    I’ve learned a lot about how body composition works and that I can weigh more but be smaller in inches. I was 16lbs heavier than my college weight but wearing the same size clothes after a year of crossfit. The data showed that getting to my college weight would mean I had to lose muscle. So it reset my expectations on the scale. One day I am going to throw that damn thing out and just use a measuring tape and a yearly scan to monitor the situation!

    Good luck with it all!

    Reply

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