A DEXA Scan is a reliable, gold-standard way to precisely measure body composition (I discussed this in my book Essential Sports Nutrition). DEXA stands for dual energy x-ray absorptiometry. More than just a weight, a DEXA Scan tells you what you are made up of - muscle, fat and bone. You can see muscle asymmetry, visceral fat and bone density.
For the athlete with excessive body fat, weight loss may improve health and sport performance. However to pressure from society, coaches and social media, it’s not uncommon for many athletes to have body image struggles, feeling like the body should always look differently. Because many athletes resort to unsafe weight loss methods and strategies when feeling “fat”, the first step in a weight loss program is to gather baseline information of your current body composition – what are you made of? Your bathroom scale does not tell you what you are made of - it only tells you a number.
Understanding body composition
Your body weight is made of two parts: body fat and lean body mass.
Body fat can be divided into two types; essential fat and storage fat. Essential fat is stored in organs, like the heart, lungs, spleen, kidneys, intestines and liver, as well as in muscle tissue, the central nervous system and bone marrow. Although a small amount stored in the body, the body requires this type of fat for bodily processes. Essential fat is very important for your overall health. Women have more essential fat than men for child-bearing purposes. Essential fat is also needed for hormone related functions.
Storage fat (the more familiar fat) consists of fat accumulation in adipose tissue. Subcutaneous fat helps to protect the skeletal structure and to conserve body heat. Visceral fat (or abdominal fat) lies just beneath the skin surface. An excessive amount of visceral fat has been linked to health issues. It's important to know your android fat level and gynoid fat level (and ratio) for metabolic health. Gynoid fat storage (pear shape) is common in women as this fat is stored primarily around the hips and thighs. This storage is often seen as healthy for child bearing. Android fat (apple shape) is stored in the midsection, predominately in the abdomen, but can be also be found in the chest and upper arms. This type of fat is consistently shown to place people at a higher risk of heart disease, diabetes, hormonal issues and more. Knowing the distribution of fat in your body can be helpful to monitor health risks and to minimize health issues later in life. Because a DEXA scan measures different types of fat in every region of your body (even your head!), the ratio of android to gynoid fat (A/G ratio) is something to monitor. You want this ratio below 1.0.
Lean body mass is everything that is not fat. Your bathroom scale doesn't know how much of your body is lean vs. fat. For example, your scale doesn't tell you the weight of your bones, organs, muscles, fluid, ligaments and tendons. More so, if your body composition is changing, your weight won't tell you why it's changing - is it more/less fluid, more/less muscle, more/less fat, more/less bone?
When we think of words like lean, fat or overweight, what do those words really mean? For example, according to a height and weight table, I may be classified as normal weight (but on the high end), but this table doesn't take into account my muscle mass and bone density. And although excess body fat can have an impact on your overall health, you do need body fat for important bodily functions.
If you are concerned or interested in your body composition, I highly encourage you to ditch the scale and get a DEXA scan. The DEXA Scan website will help you find the nearest location (and pricing) to get your body composition tested. Although not every center with a DEXA scan is listed on this website, it's a good starting place. The average price of a DEXA scan varies from $50-150 (on average). I'd say that's extremely reasonable, considering all the information you receive and the ease of the test. It only takes ~6-8 minutes for the machine to run the scan on you - while laying down - and you immediately get your results right after the test.
Because a DEXA scan tells you a tremendous amount of information about your body composition, here are some practical applications from the analysis of your body composition:
- If you feel the need to change your body composition, you should know exactly what you are made of before attempting to change your diet or exercise regime. And because you can't target your fat loss or spot reduce, even if you try to build muscle or reduce body fat, repeated testing (ex. every 3 months) can show you trends over time after establishing a baseline - particularly, how your body composition has changed over time. This will also emphasize the fact that healthy and sustainable body composition changes can not be quickly achieved, especially through extreme exercise or strict eating methods. Far too many athletes overexercise and undereat for the reasons of wanting to weigh less to perform better. If you are serious about changing your body composition, you need a very specific program/approach that will help you achieve your goals (ex. decrease body fat, increasing muscle) without compromising your health, performance and quality of life. And because body composition changes don't guarantee performance improvements, your primary focus for changing body composition should be for health reasons - not aesthetics.
- Although a DEXA scan is not a bone density exam, it does give you a general overview of your bone strength. As an athlete, you should be very concerned about this number. A high bone density (higher Z-score), means strong, healthy bones. Interestingly, a DEXA scan may tell you about imbalances, that may have resulted in (or predispose you to) an injury. This information may help your PT/trainer better understand the exercises that you need to be doing to rehab appropriately (after an injury) or to reduce the risk of an injury. For example, in the DEXA scan, you can see the difference between your right side and left side bone density. A large imbalance may indicate a muscle imbalance from a past muscle injury or an injury waiting to happen.
- Body weight is a sensitive topic and many athletes are trying to avoid the scale for that reason. I agree - the scale is not a good indicator of your self-worth, athletic talents or overall health. Because poor body image can lead to obsessive behaviors (ex. eating/exercising), a DEXA scan may give you reassurance and satisfaction that your body is actually in great health. I feel there's something extremely powerful in knowing exactly what you are made of - it also shows you how incredible your body is because of all that it's made of. Plus, if you have recently gained or lost weight, you want to be assured that it's the "right" kind of weight. For example, you could avoid carbohydrates for a few days and lose a lot of water weight. Your weight may be lower but your weight loss likely didn't come from fat.
Karel and I found this experience to be very enlightening. We never obsess about our weight/body image and our eating habits are not regimented or strict. The information we received from our scans was more about knowing what we are made of, instead of feeling like we need to use this information to make changes. We don't plan on making any changes with our diet (or training) to change our body composition for we are both healthy, performing well and enjoy our current style of eating/training. Plus, we feel our body composition naturally changes throughout the season based on our ability to adapt to training stress and recover between sessions. We also know that serious health issues can occur from getting too lean (the body gets weaker, not faster). And seeing that it's only June and we still have over three more months of Ironman specific training, we don't want to jeopardize our health in favor of attempting a leaner body composition.
Here is a recap of our body composition analysis from the Lovelace Family Medicine Center in Prosperity, SC.
Here is a recap of our body composition analysis from the Lovelace Family Medicine Center in Prosperity, SC.
KAREL
Weight (weighed with shoes and clothes on, I feel this should have been a naked weight): 145.0 lb
Height (shoes on - I feel they should have taken our shoes off): 67.5 inches
Body fat percentage: 12.4%
Android: 13%
Gynoid: 13.6%
Android/Gynoid ratio: .96
L Arm: 10.7% fat
R Arm: 11.3% fat
L leg: 12.9% fat
R leg: 12.2% fat
Head: 21.7%
Z score: 0.1
T score: 0.1
(a score of -1.0 or above is normal bone density. A score between -1.0 and -2.5 means low bone density or osteopenia and -2.5--4 is osteoporosis. A T-score is your bone density compared to what is normally expected in a healthy young adult of your sex. Your Z-score is the number of standard deviations above or below what's normally expected for someone of your sex, age, weight, ethnic or racial origin).
L Arm: 0.950 BMD (bone mineral density, the amount of bone mineral in bone tissue)
R Arm: 0.997 BMD
L Ribs: 0.736 BMD
R Ribs: 0.639 BMD
T Spine: 0.887 BMD
L Spine: 1.093 BMD
Pelvis: 1.205 BMD
L Leg: 1.251 BMD
R Leg: 1.254 BMD
MARNI
Weight (weighed with shoes and clothes on, I feel this should have been a naked weight): 114.0 lb
Height (shoes on - I feel they should have taken our shoes off but I'll take the height increase :): 61.5 inches
Body fat percentage: 17.1%
Android: 13.9%
Gynoid: 23.2%
Android/Gynoid ratio: .60
L Arm: 16.5% fat
R Arm: 14.3% fat
L leg: 21.3% fat
R leg: 19.5% fat
Head: 21.3%
Z score: 0.5
T score: 0.8
(a score of -1.0 or above is normal bone density. A score between -1.0 and -2.5 means low bone density or osteopenia and -2.5--4 is osteoporosis.)
L Arm: 0.794 BMD (bone mineral density, the amount of bone mineral in bone tissue)
R Arm: 0.842 BMD
L Ribs: 0.571 BMD
R Ribs: 0.632 BMD
T Spine: 0.966 BMD
L Spine: 1.212 BMD
Pelvis: 1.078 BMD
L Leg: 1.128 BMD
R Leg: 1.148 BMD
Although athletes tend to have lower body fat percentages, extremely low body fat can pose health issues - for men and women. When it comes to seeing where you stack-up with your body composition compared to someone else, be mindful that your body is unique. We must keep in mind that there an extreme variability of body shapes, sizes, heights, bone structure, genetics, weight and fat and muscle distributions. No two bodies are the same so it's not worth comparing your body composition (or image) to that of another athlete. Two athletes, each with 15% body fat can look extremely different. You can also be very fit at different body fat percentages. You can also be extremely lean but in poor health. This is why it's also important to never assume that weight loss will result in performance gains. Through DEXA testing, you can see how your body is put together and what you are made of. It's up to you if you want to do anything with that information.
Final thoughts....we found this process informative. I saw this as a wonderful opportunity to see how strong and healthy my body is in the inside and to see what I am really made of. Because athletes can become so overly focused on body image, make sure you are spending your energy in the right place - to become a stronger, healthier and better athlete. Performance gains don't come quickly and you should never make assumptions that lean = fit. Strive to be in great health and don't tie your happiness, confidence and self-worth to an image or body composition.
If you are interested in getting your body composition tested, you can use this link, DEXA Scan, to find your nearest location.
Final thoughts....we found this process informative. I saw this as a wonderful opportunity to see how strong and healthy my body is in the inside and to see what I am really made of. Because athletes can become so overly focused on body image, make sure you are spending your energy in the right place - to become a stronger, healthier and better athlete. Performance gains don't come quickly and you should never make assumptions that lean = fit. Strive to be in great health and don't tie your happiness, confidence and self-worth to an image or body composition.
If you are interested in getting your body composition tested, you can use this link, DEXA Scan, to find your nearest location.
I was not paid to write this post and all thoughts/feedback are my own. In return of this blog post, I received two complimentary DEXA Scan tests at a location of my choice. The closest location per the DEXA Scan website was ~90 minutes away. The test was performed on June 4th, 2019.