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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.
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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
The Deuterium Dilution Method is currently used as a typical method to measure total body water (TBW) percentage. In
contrast, this instrument estimates TBW by using BIA. An agreement of over 80% is obtained between this instrument
and the Deuterium Dilution Method.
Note: The Deuterium Dilution Method measures total body water based on the analysis of the deuterium oxide isotope in urine before and after
ingestion of an oral dose.
Normal Total Body Water Percentage (% TBW)
The normal total body water percentage ranges for adults are:
Female: 45-60%
Male : 50-65%
Note: The total body water percentage of a person with a high percentage of body fat may fall below the normal ranges.
Daily Rhythm of Total Body Water
Try to monitor 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. Total body water percentage
is not affected by fluids consumed until they are absorbed by the body tissues.
Important Notes
• Take your measurements at the same time of day and under the same conditions.
• Measured results depend on the redistribution 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 fluids 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 symptoms.
• This instrument does not directly measure an individual's total body water content. The percentage reading from the
monitor is only an estimate. Look for long-term changes and try to maintain a consistent, healthy total body water
percentage.
• This instrument will not give total body water readings for children.
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WHAT IS BASAL METABOLIC RATE (BMR)?
WHAT IS BMR?
Your Basal Metabolic Rate(BMR) is the minimum level of energy your body needs when at rest to function effectively
including your respiratory and circulatory organs, neural system, liver, kidneys, and other organs. You burn calories when sleeping.
About 70% of calories consumed every day are used for your basal metabolism. In addition, energy is used when doing any kind of
activity however; the more vigorous the activity is the more calories are burned. This is because skeletal muscle (which accounts for
approximately 40% of your body weight) acts as your metabolic engine and uses a large amount of energy. Your basal metabolism is
greatly affected by the quantity of muscles you have, therefor increasing your muscle mass will help increase your basal metabolism.
By studying healthy individuals, scientists have found that as people age, their metabolic rate changes. Basal metabolism
rises as a child matures. After a peak at the age of 16 or 17, it typically starts to decrease gradually.
Having a higher basal metabolism will increase the number of calories used and help to decrease the amount of body fat.
A low basal metabolic rate will make it harder to lose body fat and overall weight.
HOW DOES A TANITA BODY COMPOSITION MONITOR CALCULATE BMR?
The basic way of calculating Basal Metabolic Rate BMR is a standard equation using weight and age. Tanita has
conducted in-depth research into the relationship of BMR and body composition giving a much more accurate and
personalized reading for the user based on the impedance measurement. This method has been medically validated
using indirect calorimetry (measuring the breath composition).*
*Reliability on equation for Basal Metabolic Rate: At 2002 Nutrition Week : A Scientific and Clinical Forum and Exposition Title:
International Comparison: Resting Energy Expenditure Prediction Models: The American Journal of Clinical Nutrition
