Health and Fitness Information Center

Tanita Body Fat Frequently Asked Questions, Part

• Health Topics

• Asthma/Allergies
• Blood Pressure
• Blood Testing
• Body Fat Measuring
• Breast Exam
• Breastfeeding
• Cholesterol
• Defibrillator
• Diabetes
• Family Health
• Fitness
• Nutrition
• Safety
• Stress
• Thermometry
• Weight Control

Also, severe calluses or hard skin on the soles of the feet can affect the reading. The body fat monitor cannot detect body fat of less than 3%.

10. Why is my body fat % different when I change the male/female/athlete setting?
The Tanita Body Fat Monitor does not measure body fat directly. The only two values measured directly are weight and impedance; % body fat is calculated using an equation based on these and other values such as height, gender, activity level etc. Impedance is measured by sending a low, safe electrical signal through the body, and can be described as a measurement of the strength and speed of that signal.

Because muscle tissue has a high water and electrolyte content, the electrical signal passes through with ease. However, when the signal encounters fat mass, it must work harder to pass through because fat contains only a small percentage of water. Men, women and children have differing bone structures, and different ways of depositing fat around the body.

During extensive research, Tanita found that it was necessary to develop individual equations to reflect these differences. In a similar way, research showed that a further equation was necessary to maintain accuracy in the elite athletic population to address a change in water to muscle ratio seen in athletes who exercise at intensive rates over long periods of time. Since the equations have been developed to give different results to reflect a person's body type, if you use the wrong equation, you will get a wrong result. This is similar to "cheating" the scales by holding weights, or holding on to something to get a lighter weight - an interesting experiment, but an invalid result.