Tanita UM-041: PRINCIPLES OF ESTIMATING BODY FAT PERCENTAGE

PRINCIPLES OF ESTIMATING BODY FAT PERCENTAGE

Tanita Body Fat Monitor/Scales allow you to determine your body fat percentage at home as easily as you measure your weight.

What is Body Fat Percentage?

Body fat percentage is the percentage of fat in your body. Too much body fat has been linked to conditions such as high blood

pressure, heart disease, diabetes, cancer, and other disabling conditions.

1,2

Body Fat Ranges for Standard Adults

Underfat

Healthy

Overfat

Obese

1

Female 20–39

Based on NIH/WHO BMI Guidelines.

Age 40–59

2

As reported by Gallagher, et al,

60–79

at NY Obesity Research Center.

To determine the percentage of body fat

Male 20–39

that is appropriate for your body,

Age 40–59

consult your physician.

60–79

Underfat

Healthy

Overfat

Obese

With this device, persons 18 and 19 years old should use the evaluation scale for persons 20 - 39 years old, and persons age 80 and

over should use the evaluation scale for persons age 60 - 79.

The BIA Method

Tanita Body Fat Monitor/Scales use the BIA (Bioelectrical Impedance

Analysis) technique. In this method, a safe, low-level electrical signal is

Tanita’s patented “foot-pad”

passed through the body. It is difficult for the signal to flow through fat in

design sends a safe, lowlevel

the human body, but easy to flow through moisture in the muscle and other

electrical signal through the body

body tissues. The difficulty with which a signal flows through a substance

to determine its composition.

is called impedance. So the more resistance, or impedance, the signal

encounters, the higher the body fat reading.

Body Fat Percentage Fluctuations in a Day

Hydration levels in the body may affect body fat readings. Readings are usually highest in the early waking hours, since the body

tends to be dehydrated after a long night’s sleep. For the most accurate reading, a person should take a body fat percentage reading at

a consistent time of day under consistent conditions.

Besides this basic cycle of fluctuations in the daily body fat readings, variations may be caused by hydration changes in the body due

to eating, drinking, menstruation, illness, exercising, and bathing. Daily body fat readings are unique to each person, and depend

upon one’s lifestyle, job and activities.

What is Total Body Water Percentage?

TotalBodyWaterPercentageisthetotalamountoffluidinaperson’sbodyexpressedasapercentageoftheirtotalweight.

Approximately 50 –65% of the weight of a healthy person is water. Water plays a vital role in many of the body’s processes and is

found in every cell, tissue and organ. Maintaining a healthy total body water percentage will ensure the body functions efficiently and

will reduce the risk of developing associated health problems.

How To Measure Total Body Water?

Deuterium Dilution Method is currently used as a typical method to measure a total body water percentage. This instrument estimates

the total body percentage by the analysis (Multiple Regression Analysis) based on the parameter found by the BIA method.

A mutuality over 0.8 is obtained between this instrument and the “deuterium dilution method”.

Note: Deuterium Dilution Method is in terms of total body water based on the analysis of the dilution of orally ingested deuterium

oxide in urine.

Normal (Female) Normal (Male)

method [%]

method [%]

TBW by D20 dilution

TBW by D20 dilution

TBW by BIA [%] TBW by BIA [%]

Healthy Total Body Water Percentage (%TBW)

The average total body water percentage ranges for a healthy adult are:

Female: 45 to 60%

Male: 50 to 65%

Note: The total body water percentage of a person with a high percentage of body fat may fall below the average healthy ranges.

Daily Rhythm of Total Body Water

Try to measure total body water percentage at the same time of day and under the same conditions. This increases the accuracy of

the readings. The best time is in the early evening, before the evening meal, when hydration levels are more stable. Total body water

percentage tends to be underestimated to a degree if measured immediately after getting out of bed, not only because of dehydration

but also because the fluid in the body will be stored centrally in the body’s trunk.

As the day progresses this fluid becomes more evenly distributed due to the effect of gravity.

On the contrary, it may be overestimated after exercise or taking a bath because of the movement of body water or a rise in

the body temperature despite actual dehydration.

Important Notes

•Takeyourmeasurementsatthesametimeofdayandunderthesameconditions.

•Measuredresultsdependonthemovementofwaterinthebodyand/orchangesinbodytemperature.Factorsaffectingtotalbody

water levels include sleep, physical activity, eating and drinking, illness and medications, bathing patterns and urination.

•Takefluidimmediatelyifyouhaveanysymptomsofdehydration,particularlyafterphysicalactivityorbathing.

Symptoms include a dry mouth, headache, nausea, dizziness, skin dryness, a rise in temperature, loss of concentration, etc. If

symptoms persist, consult your doctor immediately.

•Elderlypeopleareatincreasedriskofdehydrationastheyhavelesssensitivitytothirstandotherrationalsymptoms.

•Thisinstrumentcannotbeusedtospecificallydetermineanindividual’srecommendedtotalbodywaterpercentage.

Look for the long-term changes in total body water percentage and try to maintain a consistent, healthy total body water percentage.