Most people are so obsessed with their body weight and the reading on their bathroom scale, they believe this is a measure of everything from fatness to fitness to wellness to their entire self-perceived worth. Gorgeous people, please take note, this does not reflect body composition, please don’t give up on your fitness goals if the needle on your scale hasn’t moved. By strictly listening to only your bathroom scale and obsessing over your body weight, you may have greater health implications later in life, it may eventually lead to major health risks. Accurate body composition assessments are important to make effective, positive changes to your diet, exercise and lifestyle.
What is body composition?
Body composition is used to describe the matter of which the body is made up of, looking at the measurements of fat mass and fat free mass (fat free mass is muscle mass, bone content, organs, minerals, blood and body water). It is so important to consider overall body composition rather than body weight to accurately determine and track changes to reduce health risks. Body composition is basically what we are made of. Remember, just because we have fat does not mean we are fat! 😊
Many people often misunderstand body composition and how it changes over time, especially when starting on a fitness regime. Most are not aware of or fail to acknowledge that muscle mass is denser than fat mass so often we may gain weight on the bathroom scale while in fact we are losing body fat and becoming leaner and slimmer. Many methods such as Body mass Index (BMI) assessment and relying only on body weight are dangerous, as they can overlook major health risks since they do not consider body composition or fat distribution.
When embarking on a fitness journey, nearly all people look for an effective method of tracking their progress. We all want to know if what we are working so hard for, is reachable and we are achieving the changes we are looking for. We want to know where we started, what our goals are and how far we still need to go. We want to see evidence that our hard work is paying off otherwise we grow despondent and negative and will normally think “what’s the point, I give up”.
The objective of this fitness and wellness blog is to discuss the different body composition assessment methods and find the best method for you to ensure you stay motivated and on track.
At REBIRTH we analyzed over 80 articles and research papers, and conducted studies with numerous personal trainers, nutritionists, and fitness experts across the world to validate our data.
Our findings reveal that the most accessible assessment methods such as BMI (Body Mass index) and the bathroom scale, lack greatly in accuracy, frequently providing false readings with no consideration of body composition. Whilst the most technologically advanced methods such as DEXA (dual-energy x-ray absorptiometry) and MRI’s provide accurate readings but are not easily accessible and are too expensive for many people. Our studies have found that the validity of body composition findings is greatly enhanced by using a combination of methods and techniques, namely the skin fold technique or bioelectrical impendence analysis (when available) combined with girth measurements.
There are many ways to determine body composition with different levels of accuracy. The most important aspect to consider when choosing the preferred method, is to consider what the purpose of the assessment is. Are you trying to track your progress, are you looking to identify possible health risks, do you want to just see your current state, or are you a super athlete looking for exact scientific data to enhance your performance and win the Olympics?
Accuracy is not the be-all-end-all in assessing body composition. Sometimes consistency in measuring is more important when tracking fitness goals. Other factors are important to consider too including accessibility / convenience and the cost of the assessment. Most gyms only offer BIA and the bathroom scale with personal trainers assessing body composition with skin fold and girth measurements. DEXA is available at medical centers for body composition assessment purposes but the cost of the assessment is high for most people. It is very difficult to access ADP, hydrostatic weighing, and MRI / CT scanners for this purpose so we will ignore these in this article. If you are interested in discussing these feel free to contact us at REBIRTH and we will be happy to share our knowledge.
Body Mass Index (BMI)
Body Mass Index (BMI) is simply a weight to height ratio. It categorizes people into weight groups to identify current or future health risks.
Determining BMI is a simple formula of (body weight in kilograms) divided by (height in meters squared). It is sex and age dependent, so it needs to be mapped against a chart.
The application of BMI was intended only for mass adult based studies at population level to assess body weight normalcies and identify possible health complications. It was developed by a Belgian astronomer, mathematician, statistician and sociologist, Adolphe Quetelet, in the 1830’s. The World Health Organization (WHO) and many medical professionals use BMI as a global index of nutritional status to identify global population risks of world hunger or obesity.
BMI it is not and should not be used as a diagnostic tool as it fails to differentiate between fat mass and fat free mass. Since our fat distribution is different in each of us (depending on our body type) as a result of hormonal balances it is not an accurate method of determining body composition. It is however noninvasive, cheap and easily accessible to most with the only required tools of a bathroom scale and a stadiometer (height measuring tool).
Since it does not consider fat distribution it is highly inaccurate. BMI claims that the healthiest athletes and influencers are anorexic or morbidly obese.
Please don’t use BMI and let it influence your mindset and distort your self-perception.
Skinfold Test
Some of your personal trainers may have already suggested this skinfold or pinch test to you, some of you may have already done it.
It is used to measure the thickness of subcutaneous (surface) fat at different areas (called sites) on the body. The test is generally conducted on 7 sites and may include areas such as the chest / pectoral, triceps, biceps, midaxillary (under arm / bra line fat), belly / abdominals, subscapular (shoulder blades), suprailiac (love handles / upper hips), thigh and medial calf. The sites chosen may differ for men and women. The assessment assumes that the fat tissue compresses in a certain manner and that the skin thickness is ignored. This assessment is frequently used as it is practical, the calipers are small and light to carry, they are easy to use and are inexpensive. They are however considered unsophisticated, intrusive (many people do not like to feel their fat being pinched and pulled) and it is easy for the operator to make mistakes. The assessment must be conducted by a trained professional with basic knowledge of anatomy.
Accuracy may vary based on the operator’s experience, the sites measured, and the equation (needs a complicated formula) used to convert into body fat percentage. If a client is assessed over a period to track changes, the accuracy may differ if the site measured in not the same as before or if the time of day is different. It is not advised to assess morbidly obese people as the folds may be too large. Please note that this assessment method does not consider deep belly fat which may pose a potential health risk and may be overlooked.
For the skinfold assessment, consistency is key. Consistency trumps accuracy. It is advisable to measure and maintain raw data for comparable future assessments and do not use an equation as the wrong equation may be misleading. It is best not to convert to body fat percentage as the forumal used might have been developed for a different ethnic or gender group. If you don’t feel it is intrusive then it is great to use as a tracking method.
If you insist on your personal trainer converting to a body fat percentage, then we suggest using the popular Jackson and Pollock equation, the Durnin and Wormersley equation or the Petroski equation.
Girth / Body circumference measurements:
Girth (circumference) measurements are commonly used by personal trainers / fitness trainers, clinics and public healthcare providers as it is quick, easy to measure and it offers raw data to analyze patterns of fat distribution and changes over time. Girth body measurements are an excellent way to analyze body fat distribution patterns and to predict body fat percentage. The areas / sites typically used are areas with high fat deposits in the human body, so this method offers accurate assessment of bodily changes. The method of girth assessment is to measure the circumference with a plastic or linen measuring tape. The tape should be taught but not tight and should be level across the circumference -so it is best to get someone to help you. The individual being measured should stand relaxed, do not pull in the belly / abdomen and look straight ahead. It is advisable to duplicate the measurements three times then take an average score at each area / site.
The accuracy is dependent on the operator’s due diligence. Like the skinfold method, consistency trumps accuracy. Rather measure consistently incorrectly in the same area / site than strive for accuracy adjusting the sites.
Some girth measurements may include areas such as Neck, Bicep (right hand side), Tricep (right hand side), Forearm (right hand side), Abdominals, Hip (at largest) Thigh (right hand side), and Calf (right hand side).
Rebirth’s favourite girth measurement to identify health risks is the waist to hip ratio as it measures the areas / sites with the largest fat deposits in all genders, being the waist at the narrowest and the low hip at the widest. The waist measurement is then divided by the hip measurement and risk can be determined according to the chart below. It is highly accurate, very easy to measure and non-intrusive.
Bioelectrical Impedance Analysis (BIA):
Some of you may have heard of, or even used the In-Body machine in your gym or clinic. This is a brand name for a BIA device.
The BIA is an amazing tool (depending on the brand you have access to) as it uses electrodes to send weak electrical currencies through the body. It measures body composition by calculating resistance (impedance) of the voltage through the body. It works on the fact that most of the water in our bodies are stored in our muscles and water is a great conductor of electricity whereas fat is an insulator so will create resistance against the electrical current. Therefore, the more muscle mass, the more water, the less impedance. It considers age, sex, height, weight and sometimes race variables to improve accuracy. It treats the body as a single cylinder and either measures from hand to leg or leg to leg depending on the model. Devices such as the InBody brand as considered highly accurate as they measure five cylinders, the trunk (which accounts for 50% of total body weight) and the four limbs using 8 electrodes from ankles to wrists. The more nodes (metal parts that touch your skin) the more accurate. The measurements are conducted multiple times to find the average impedance. The InBody auto-calibrates when the machine is turned off to adjust to environmental electromagnetic currents and room temperature, which could affect accuracy. It is recommended to use the BIA several hours after training and a few hours before eating or drinking anything (have an empty stomach for at least 4 hours – no water either).
Dual-Energy X-Ray Absorptiometry (DEXA):
DEXA is considered the most accurate but also most expensive methods to measure. Rebirth only suggest super athletes who require extremely detailed, accurate assessment methods use this.
The dual energy x-ray absorption (DEXA or DXA) uses two x-ray beams sending energy to the bones. It uses the energy absorption to create pixels and form a “fatness” image of the body. DEXA removes the soft tissue absorption to determine the bone mineral density. It can report on three components, fat-mass, fat-free mass and bone mineral density. The scan is influenced by trunk thickness and does not require biological constancy assumptions such as fat mass and fat free mass. DEXA is normally used to detect osteoporosis but due to its ability to generate a low-resolution fat shadow it is a highly effective tool for body composition analysis. The scan is widely used and non-invasive but normally only found in hospitals and clinics. Due the size and cost of the equipment it is not typically found in gyms.
DEXA is known as the gold standard in body composition analysis so if you want to nerd out and don’t mind spending, then this is your best option.
Conclusion
There are many methods available to determine body composition and no method is perfect. So, we need to decide why we want to know our body fat composition to choose the best method.
Most people are focused on losing weight, not fat. As a fitness instructor, I like to educate my clients on this misconception to keep them motivated and help them keep track of their goals. Since most of us just want to track our body fat changes whilst on our fitness journey, I suggest 3 invaluable methods:
Photos: take photos of yourself (nearly naked) every week. If you are wearing underwear be sure to wear the same underwear in every picture. These photos are not intended to be shared with anyone – they are for you. When you feel you are not making progress or you start questioning why you are working so hard and you feel you are not seeing results, just go back and compare your photos. You will be amazed and so proud of how far you have come and how quickly your body changes. I still do this at certain points in my life – this is my most valuable tool to stay motivated.
Girth / circumference measurements
I also recommend taking measurements once or twice a month. Choose the best areas / sites you want to measure (some mentioned above) and stick to the same measurement every time. Save the results and track your progress on how many centimeters your body has changed.
How you feel: This, to me, is the most important measure of your fitness success. How do you feel? More energized, happy, calm, positive, loved? Being healthy and achieving your “ideal” body is not about the numbers on the scale or about the weight that society thinks you should be. It is about how you feel. Whatever weight or measurement you are at when you feel the best and most alive, is your ideal weight.
And please try to be patient with yourself, it takes time to really see the changes in your body. You didn’t get out of shape overnight, so don’t think you can get back in shape overnight. And always remember, you can’t rush something that you want to last forever! Consistency gets results, not perfection.