Body Composition
Why is it important?
You May Be Over-Fat Even If You're Not Overweight
Research has shown that body composition is directly related to health. Even if your BMI (Body Mass Index) calculation appears to be healthy, this may not be giving you the true picture. Let me explain further.....even if you do not consider yourself to be overweight, you may actually have too little muscle and too much fat, a condition called "sarcopenic obesity". Sarcopenia is the medical term that describes the age-related loss of muscle mass and function. A proper muscle-to-fat ratio has been associated with longevity and reduced risk of chronic disease - but you can't measure body composition by stepping on a scale.
How Do You Measure Body Composition?
Measuring body composition is rapidly becoming an integral part of health and nutritional assessment. Several methods are available to accurately measure body composition.
- Bioelectrical Impedance Analysis (BIA) : BIA is a simple, rapid and accurate method of assessing body composition that uses electric signals at different frequencies, which are impeded variably by body water, fat and fat-free mass.
- Dual Energy X-Ray Absorptiometry (DEXA) : DEXA uses low-energy X-ray science to measure muscle-to-fat ratio. Because this approach calculates fat mass and two components of fat-free mass (bone mineral and lean tissue), DEXA is an accurate measure of body composition.
- Skin-Fold Thickness : Skin-fold thickness is the most widely used method for assessing body composition. This assessment uses skin-fold calipers designed specifically to measure subcutaneous tissue at the triceps of other specified locations on the body.
- Waist Circumference : While waist circumference does not accurately evaluate body composition, it is a practical tool for measuring your abdominal fat. Abdominal fat is associated with a greater health risk than fat located around your hips.
What Causes Sarcopenia (Muscle Loss)?
The first and most obvious cause is lack of exercise. To maintain muscle, you have to exercise. But that’s not the whole story. Researchers are discovering that insulin resistance and immune factors produced in response to the food we eat are important causes of sarcopenia.
Insulin Resistance – The Concept
Insulin is a hormone produced by your pancreas that transports glucose (blood sugar) from the bloodstream into your cells where it is used to make energy. However, in many people the cells become resistant to the action of insulin – a condition called insulin resistance. To compensate, the pancreas goes into overdrive and secretes even more insulin in an attempt to counteract the resistance. If this process continues long term, insulin resistance can lead to reduced energy production throughout the body, reduced ability to burn calories, increased blood sugar levels and muscle loss or sarcopenia.