Body-fat!

Basic Definitions and Concepts in Body Composition
Body composition refers to the make up of lean tissue and fat tissue in the body. So:

• Lean Tissue - Composed of muscle, bone, organs, glycogen, blood volume, water, hair, nerves and a few other bits and pieces.
• Fat Tissue - Composed of different categories: essential fat, and storage fat.
• Essential fat - Required for life and physiological functioning. This is fat stored/ that is part of nerves, bone marrow, the organs (heart, lungs, liver, spleen, kidneys, intestines) and also the muscles. There is thought to be ~ 8-12 % in females and ~ 3-5% in males. The extra 'fat' that is essential for females is thought to be due to our requirement for babies and hormones. It is essential RESERVE fat found in breast tissue, genital regions and *gasp* lower body stores.
• Storage Fat - The 'cheese' factor. Generally divided into - VISCERAL fat (around organs and in the abdomen) and SUBCUTANEOUS fat (under the skin). In females, this is usually about 15% and males it is about 12%.

Measuring Body Fat %
There are many, many ways to find out your body fat percentage, and these all vary in accuracy and availability. Generally speaking - the more accurate the method, the more expensive and 'unobtainable' it is. Going from MOST accurate to LEAST accurate:

• DEXA scan – This involves a full body x-ray like that used for bone density scans. It is very accurate (although there WILL be a variation between machines - so best to get it done on the same machine by the same technician). There IS also a radiation factor (something to consider if getting multiple scans).
• Underwater/ Hydrostatic Weighing (also called water displacement) – An individual is submerged and weighed under water, with all the air blown out of their lungs and a percentage of fat and fat-free weight is calculated from body density. Very accurate when done professionally but not widely available.
• The Bod Pod - Similar concept to underwater weight, but the individual is placed into a small chamber and the amount of air displaced is measured by sensors and calculated into a BF %. Also accurate, but not widely available.
• Skin-fold measurements/ calipers – Folds of skin are measured with a caliper (pinching tool). The measurements are used in equations that link the thickness of skinfolds to percent body fat calculations. It can be done via '3 sites', '4 sites' and '7 sites'. The more measurements made, the more accurate the estimate. It is simple and available, but needs to be done by someone who is trained and there are wide variations in accuracy.
• Bioelectrical Impedance (BIA) – These are scales or hand-held devises that run an electrical current through the body to determine water content. They vary in accuracy according to the specific device (some brands are better than others), the number of attachment points (foot and hand electrodes are more accurate than hand held or scale devises), and the user. Example: if you use a SCALE only - the electrical impulse takes the path of least resistance - so travels up one leg, and straight down the other. Thus, it basically measures LOWER body %. If you use a hand held device, it only measures UPPER body %. Similarly - As they are based on WATER content - fluctuations in hormones/ hydration throw values out. So - the best results are obtained first thing in the morning after emptying bladder/ bowels, with no alcohol consumed for 2 days prior, and no exercise the night before, and - hormone free.
• Tape measure method - There are a number of formula based on several body measurements taken with a tape measure. It can be roughly accurate, but it does depend upon your ability to accurately measure as well as body shape/ type. Although LEAST accurate - it is especially useful for tracking yourself over time as it is readily available.

Body fat % in females
Generally speaking - most athletes range between 12-14% and 20%. Most fit females in the general community are 18-24%. Most every day females, well, usually above 24%. It is also important to note that a female who LOOKS thin does not necessarily mean she has a low body fat. This is the concept of 'skinny fat'. In females, the lowest values for body fat correspond to the essential fat content (about 8-12%). This level of fatness is extremely low (professional bodybuilder on stage low). And once a female reaches 12%, especially for prolonged periods, they will run into issues with health (lack of periods, decreased immune function, decreased recovery, decreased bone mass, etc).

Body Fat Categories for Women:
8-12% - Essential Fat
13-20% - Athletic Fat Levels
21-24% - Fitness Fat Levels
25-31% - Acceptable Fat Levels
>32% - Obese


Visual Estimates and why is it so inaccurate?
There are many reasons - firstly, people look different at different at the SAME body fat depending on where they hold their fat, and how much lean mass they have. Additionally, people make the mistake of comparing visual estimates in females and males - and, as discussed above, this is NOT correct... Essentially, you need to add on another 5-8% to a MALE estimate for an accurate guess for a female visual %. For example: a male 10% is roughly a female 15-17%. A male 3-5% is a female 8-12%.

It is also important to note that you need to look at the WHOLE person! So - in females, where UPPER BODY might be lean (eg: 10-12%), LOWER body may well still hold a LOT of fat (female stubborn fat) which will INCREASE their average bodyfat %.

Generally speaking - visual cues to look for in females:
- Upper back definition and shoulder/ delts usually come in first in females [mid to high teens]
- Abs separation and pec separation follows this [usually low to mid teens]
- Quad definition/ ham definition and Glute striations [single digit to low teens]
But NOTE: this is 'most' females (who have typical pear-body fat distribution) if an individual holds more fat in a MALE distribution (apple) then the cues will be different.