The results obtained through Tanita BIA have been shown to be within +/-5% of Underwater Weighing and Pencil Beam DEXA (the "gold" standards of body composition analysis). 

You can read more about the accuracy of Tanita Body Composition Monitors, here.

Bioelectrical Impedance Analysis (BIA) is considered one of the most reliable and accessible methods of screening body fat. Tanita patented a revolutionary way of measuring BIA that is faster, easier and less intrusive than traditional means – being the first company to introduce the world to the body fat monitor scale in 1994. Electrodes in the foot sensor pads (and hand sensor pads if you own a segmental monitor) send a low, safe electrical signal through the body and weight is calculated automatically along with up to 25 other readings in seconds. 

BIA measures an individual’s impedance or resistance to the electrical signal as it travels through the water that is found in muscle and fat. The more muscle a person has, the more water their body can hold and the greater the amount of water in a person’s body, the easier it is for the electrical signal to pass through it. The more fat an individual has, the more resistance they have to the electrical signal.

In conventional BIA, a person is weighed, and their height, age, gender, and weight, or other physical characteristics such as body type, physical activity level, are entered in a computer. While the person is lying down, electrodes are attached to various parts of the body and a small electric signal is applied.

With a Tanita Body Composition Monitor, you add that information into the monitor when setting up your own user memory profile, which then inputs your characteristics & calculations into the correct algorithms for you to produce the measurements provided by your reading. 

BIA is safe, and a large majority of the population cannot feel the electrical signal at all, however weight-only mode should be used for those with pacemakers, ICDs and other implanted medical devices.

Most Tanita Body Composition Monitors make it possible to determine a person’s: 

• Weight 
• Body Water Percentage
• Muscle Mass
• Physique Rating
• Basal Metabolic Rate
• Metabolic Age
• Visceral Fat
• Bone Mass
• Muscle Quality 

Your total body health is more important than just one number. Measuring weight alone is not a complete nor accurate assessment of health or fitness level. 

The total body weight measurement does not distinguish the difference between kilograms that come from fat, the kilograms that come from lean muscle mass, the weight of bone mass or the impact different body water levels have on your total body weight.

Monitoring body composition allows you to gain a deeper insight into your overall body health, giving you the knowledge that you can then use to make educated changes to your diet and fitness routines to achieve your health and fitness goals sooner. 

For example, you’ve decided you want to lose weight and change your diet, and that you’re going to track your body changes through monitoring weight only. If you were to step on the scale, and see a smaller number, you may believe that you are on the right track. However, if you were monitoring overall body health on a Tanita Body Composition Monitor, the Monitor would tell you that you are dehydrated and have actually decreased your muscle mass. With this information, you would know that you’re not on the right track, and that you need to change your fitness routine and to drink more water. 

The suggestion that most people would give when asked the best time to stand on a scale would be as soon as you wake up in the morning. However, doing this will not show you a true & accurate representation of your overall total body health, especially on a Tanita Body Composition Monitor. 

Tanita Body Composition Monitors use BIA technology to generate measurements. In the monitor, the Bioelectrical Impedance Analysis (BIA) technology sends a very low and safe electrical signal through the water content present in the body. The results gathered from this signal then help to generate the measurements the monitor displays. 

As the monitor uses the water content in the body to obtain data for the reading, good hydration & healthy body water levels is key to getting the most accurate measurements from the reading. This means the best time to measure your body using a Body Composition Monitor would be the time of day when your body is consistently and naturally the most hydrated.

However, our body water levels naturally fluctuate throughout the day and night. Any significant changes in body water levels may affect your body composition readings; for example, the body tends to be dehydrated after a night’s sleep so if you take a reading first thing in the morning (like people would normally suggest), your weight may be lower and your body fat percentage would likely read higher than what is actually true. Eating large meals, drinking alcohol, menstruation, illness, exercising, and bathing may also cause variations in your hydration levels. 

To get the most reliable and accurate reading that best represents your actual total body health, use your Body Composition Monitor at a consistent time of day under consistent conditions, and at least three hours after rising, exercising, eating, drinking alcohol and taking medication.

For many, this time is usually mid-to-late afternoon, before dinner and before your afternoon/evening workout.