BF-558/559 Scale plus Body Fat Monitor
Tanita Scale plus Body Fat Monitors allow you to measure 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. Until now, your absolute weight has
determined whether or not you were considered overweight or obese. In recent years, the definition of
obesity has been refined to mean the presence of excess body fat. Obesity has been linked to
conditions such as high blood pressure, heart disease, diabetes, cancer, and other disabling conditions.
The BIA Method
Tanita Scale plus Body Fat Monitors use the BIA (Bioelectrical Impedance Analysis) technique. In this
method, a safe low-level electrical signal is passed through the body. It is difficult for the signal to flow
through fat in the human body, but easy to flow through moisture in the muscle and other body
tissues. The difficulty with which a signal flows through a substance is called impedance. So the
amount of fat in the body can be accurately estimated by measuring the impedance. The signal used is
very low, making it safe and imperceptible.
The illustration on the left shows how the signal travels through the body.
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.
Advantages of Tanita Scale plus Body Fat Monitors
Previously, body fat percentage was determined by measuring the thickness of subcutaneous fat by
pinching it with calipers, or by laying a person on a scanning bed and passing a current from hand to
foot. However, these methods had problems—professional skills are required, the procedures take time
and are often invasive, and measurement values vary. Currently, the gold standard methods of fat
percentage measurement are the
underwater weighing method
and
DEXA (dual energy x-ray
absorptiometry).
Tanita’s BIA method uses equations derived from large, multi-ethnic population studies to predict body
composition. Readings taken with Tanita Scale plus Body Fat Monitors correlate highly with both DEXA
(Tanita’s reference model) and Hydrodensitometry.
2
Tanita’s patented “foot-pad”
design sends a safe,
low-level electrical signal
through the body to
determine its composition.
20–39
40–59
60–79
Healthy
Overfat
Obese
Underfat
Healthy
Overfat
Obese
Underfat
Based on NIH/WHO BMI Guidelines.
As reported by Gallagher, et al,
at NY Obesity Research Center.
To determine the percentage of body fat
that is appropriate for your body,
consult your physician.
10%
0%
20%
30%
40%
20–39
40–59
60–79
Female
Body Fat Ranges
for Standard Adults
Age
Male
Age
1, 2
1
2
PRINCIPLES OF ESTIMATING BODY FAT %
