Body Composition

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton and Kim Jackson  

Introduction[edit | edit source]

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The body is composed of water, protein, minerals, and fat. A two-component model of body composition divides the body into a fat component and fat-free component.

  • A body composition analysis gives you a quick snapshot of your health by breaking apart your body into these two types of mass: body fat and fat-free mass.
  • Having a full understanding of body composition, by getting it properly measured, will give you personalized insights that take the guesswork out of a persons health status [1].

Body Fat[edit | edit source]

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Body fat is the most variable constituent of the body. The total amount of body fat consists of essential fat and storage fat.

  1. Essential fat is necessary for normal bodily functioning. Fat in the bone marrow, in the heart, lungs, liver, spleen, kidneys, intestines, muscles, and lipid-rich tissues throughout the central nervous system is called essential fat
  2. Body fat (storage fat) - this refers to all the fat in your body, such as the fat around your organs or abdomen (visceral) and the “jiggly” fat you see just under your skin (subcutaneous). Visceral fat (abdominal), is non-essential and having it in excess can increase susceptibility to chronic illness and health complications.

One of conditions associated with central obesity is Metabolic Syndrome

Fat-free Mass[edit | edit source]

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Fat free mass covers all the things in your body that aren't fat, including muscles, bones, water (both intracellular and extracellular), minerals, proteins, organs, and other tissues.

  • Lean body mass represents the weight of your muscles, bones, ligaments, tendons, and internal organs.
  • Lean body mass differs from fat-free mass. Since there is some essential fat in the marrow of your bones and internal organs, the lean body mass includes a small percentage of essential fat. However, with the two-component model of body composition, these sources of essential fat are estimated and subtracted from total body weight to obtain the fat-free mass. [2] [1]

Misconceptions[edit | edit source]

Standard bathroom scale will provide an easy metric for monitoring weight over time, however that number that doesn’t accurately tell the story of your health. It’s like looking at the cover of the book and thinking you know the complexities of the plot lines inside[2].

Efforts to lower or raise weight are often based on popular misconceptions about body weight and body composition. Being eg thin does not necessarily reduce one's health risk. In fact, obsession with becoming thin often leads to serious eating disorders eg anorexia and bulimia.

  • Thinness simply refers to weighing less than the recommended values in age-height-weight tables.
  • Leanness, on the other hand, refers to the muscle, bone, and fat composition of your body weight. Although some lean individuals may actually weigh more than their "tabled" ideal body weight, low body fat lessens the risk of health problems[2].

Body mass index (BMI), another frequently used measurement of health, generates a value based on height and weight that broadly categorizes you as being underweight, normal, overweight or obese. The equation however is imperfect, and can be misleading. It’s entirely possible have a body mass index (BMI) in the “healthy range” but to still be at risk for disease and chronic illness because of the way the mass in your body is distributed.

Body Composition Analysis[edit | edit source]


By breaking the body down to its core components through a full body composition analysis, you can accurately measure and track changes in muscle mass, fat mass, and body fat percentage over time which can help you identify the areas you need to work on to lower your risk of disease and improve your overall health.[1] The following are 4 body fat measurement techniques that are often accessible to fitness professionals: hydrostatic weighing, bioelectrical impedance, and skinfolds.

Image: Calipers used for skinfold tests.

  • Hydrostatic weighing, also known as underwater weighing or hydrodensitometry, is one of the most accurate ways to measure body fat. This is done by submerging yourself in a tank of water and being weighed underwater. The measurements can then be broken down to determine your fat and fat-free mass, including your lean tissue and muscle mass. May be available at local wellness clinic or doctor may be able to recommend a facility that offers hydrostatic testing. Some gyms with a pool will offer this service to clients[3]. It was considered the gold standard for measuring body composition until more advanced methods, such as CT scans and MRI scans, were developed[4].
  • Bioelectrical Impedance Analysis (BIA): This technique uses body fat and lean muscle mass as the basis for measurement by way of either a handheld device or BIA scale. Small electric currents are sent through the body and because water, fat, and lean tissue mass interact with the currents differently the devices can accurately assess the distribution of your mass.
  • Skinfold Measurements: Done by pinching the skin with calipers in seven different areas on the body, can provide a quick and relatively accurate estimate of body fat that can be compared to others of similar age and gender. This technique, while quick and requiring very little equipment, does not paint a complete picture of the different types of fat or how and where your body is storing it[1].
  • Body composition scales (local fitness store or online). A body composition scale uses a weak electrical current to measure your body fat and fat-free mass. These scales are often made of glass and steel to help the electricity conduct properly. They will have a viewing screen where you can determine your body fat percentage, your weight, and your body water percentage. Body composition scales will range in price from $20 - $100 USD. More expensive scales can be more reliable and offer more features[3].

Physiotherapy[edit | edit source]

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Knowing a clients body composition is more informative than focusing on their body weight, since it gives you measure both fat mass and fat-free mass.

  • Eg if a person begins an exercise program with you, they may gain 1 kg of muscle in the first month. At the same time, they may lose 1 kg of fat due to burning more calories through exercise or changes in your diet. Since the fat-free mass increased by the same amount as the fat mass decreased, the body weight won’t change.
  • If a person focuses on the their weight, they may become discouraged or frustrated because the program “isn’t working.” This is one example of why knowing body composition is much more useful than knowing body weight[5].

Physical activity and exercise are components for improving body composition.

  • They not only increase the calories used, but they are also necessary for optimal muscle growth.
  • Body composition can be improved by decreasing fat mass or increasing muscle mass[5].

Many types of exercise can potentially help with fat loss: Interventions that combine high‐intensity aerobic and high‐load resistance training exert beneficial effects that are superior to any other exercise modality at decreasing abdominal adiposity, improving lean body mass and increasing cardiorespiratory fitness. Clinicians should consider this evidence when prescribing exercise for adults living with obesity, to ensure optimal effectiveness.[6]

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 Fitnesity Body Composition Available: (accessed 11.11.2021)
  2. 2.0 2.1 2.2 Kravitz L, Heyward VH. Getting a grip on body composition. IDEA today. 1992;10(4):34-9.Available: (accessed 11.11.2021)
  3. 3.0 3.1 Wikihow How to Measure Body Composition Available: (accessed 11.11.2021)
  4. Healthline Hysdostatic weighing Available: (accessed 11.11.2021)
  5. 5.0 5.1 Healthline How to Improve Body Composition, Based on Science Available: 11.11.2021)
  6. O'Donoghue G, Blake C, Cunningham C, Lennon O, Perrotta C. What exercise prescription is optimal to improve body composition and cardiorespiratory fitness in adults living with obesity? A network meta‐analysis. Obesity Reviews. 2021 Feb;22(2):e13137. Available: (accessed 11.11.2021)