What are body composition scales?
A body composition scale is not just an ordinary scale. It can tell you much more than just your weight. Body composition scales provide you with detailed insight into your body composition, and thereby a more realistic picture of your health. Small and completely harmless electrical impulses are sent through the body and calculate how your body is composed of, among other things, body fat, muscle mass, and water.
What does BIA mean?
BIA stands for Bioelectrical Impedance Analysis. The technology is used to measure body composition, giving you information on everything from water and body fat percentage to muscle mass and bone mass. The small electrical impulses flow through the body and both intracellular and extracellular fluid. The signal passes quickly through fluid and hydrated muscles but encounters resistance in fatty tissue. This resistance is called impedance. Based on this, body composition is calculated. It is easy, fast, and safe, which is why it has become very popular to use body composition scales with BIA technology – both professionally and at home.
What can body composition scales show me*?
- Body weight
- BMI
- Body fat in %
- Body water/water retention in the body in %
- Muscle mass in kg
- Physical assessment
- Bone mass in kg
- Visceral fat assessment
- BMR (basal metabolic rate)
- Your metabolic age
*Depending on the body composition scale. Some body composition scales can show more information than others.
What can my body weight and BMI tell me?
Body weight is what it is, namely the total mass of the body. BMI says something about the relationship between your height and weight, but not how healthy your body composition is. If you are short and very muscular, your BMI will likely be high, even if you have a low body fat percentage. Body composition scales, on the other hand, can provide a more accurate picture of whether you are healthy or not. BMI is calculated as follows: body weight in kg/(height in meters)2.
How much body fat should you have?
The body's fat percentage varies for men and women and changes with age. What is healthy for an individual depends on gender, age, and other factors.
Women
| Age | Perfect | Normal | Average | Too High |
|---|---|---|---|---|
| 20-24 | 18.2 | 22.0 | 25.0 | 29.6 |
| 25-29 | 18.9 | 22.1 | 25.4 | 29.8 |
| 30-34 | 19.7 | 22.7 | 26.4 | 30.5 |
| 35-39 | 21.0 | 24.0 | 27.7 | 31.5 |
| 40-44 | 22.6 | 25.6 | 29.3 | 32.8 |
| 45-49 | 24.3 | 27.3 | 30.9 | 34.1 |
| 50-59 | 26.6 | 29.7 | 33.1 | 36.2 |
| > 60 | 27.4 | 30.7 | 34.0 | 37.3 |
Men
| Age | Perfect | Normal | Average | Too High |
|---|---|---|---|---|
| 20-24 | 10.8 | 14.9 | 19.0 | 23.3 |
| 25-29 | 12.8 | 16.5 | 20.3 | 24.3 |
| 30-34 | 14.5 | 18.0 | 21.5 | 25.2 |
| 35-39 | 16.1 | 19.3 | 22.6 | 26.1 |
| 40-44 | 17.5 | 20.5 | 23.6 | 26.9 |
| 45-49 | 18.6 | 21.5 | 24.5 | 27.6 |
| 50-59 | 19.8 | 22.7 | 25.6 | 28.7 |
| > 60 | 20.2 | 23.2 | 26.2 | 29.3 |
Why does my body fat percentage fluctuate so much?
There can be several reasons why body fat percentage fluctuates, and this is generally true for body composition scales. The body tends to dehydrate after a night's sleep, so if you take the first measurement immediately in the morning, your weight will be lower and your body fat percentage higher. Ingesting a large meal, alcohol, menstruation, illness, exercise, and bathing can also lead to changes in hydration. A good rule of thumb is therefore to weigh yourself at a fixed time of day, preferably in the afternoon or just before dinner.
It is also important to weigh yourself barefoot, and it is beneficial if your feet are slightly damp. If your soles are completely dry or very hard, the results may deviate because the conductivity of the feet will be less good.
When is my body water content optimal?
The average percentage for a healthy person is 45% – 60% for women and 50% – 65% for men. The amount of water a person needs varies and depends on climate and physical activity. It is important to maintain good hydration, but very active people should consume more fluids and pay particular attention to this. The recommendation is at least 2 liters of fluid daily for everyone, preferably water or other low-calorie fluids. A body composition scale that can measure both intracellular and extracellular water will therefore provide the most accurate result, as it measures both the water bound in the cells and the water outside. This makes it easier to track the effect of increasing fluid intake.
What does muscle mass show?
Muscle mass shows how many kg of your total body weight consists of muscles. This includes all muscles in the body. The higher the muscle mass, the better the body burns calories (energy). High muscle mass boosts the resting metabolic rate (also called BMR = basal metabolic rate) and helps to lose excess fat and reduce body weight in a healthy way.
What does physical assessment mean?
Tanita body composition scales define your body type based on the ratio of muscle mass to body fat on a scale from 1-9. The assessment is intended to illustrate that one can have a high muscle mass and a lot of body fat, which would be a rating of 3. High muscle mass and a low body fat percentage would be a rating of 9.
What can my bone mass tell me?
Bone mass is stated differently, depending on the body composition scale. Tanita scales will measure a healthy bone mass to be somewhere between 1.95 kg – 2.95 kg for women and 2.65 kg – 3.69 kg for men. This measurement indicates an estimate of the body's bone mineral and calcium. Beurer scales, e.g., BF 700, state bone mass with a higher value. This value will be approximately 12-15% of body weight and indicates the weight of the skeleton, including cartilage, water, and other organic substances. Bone mass is not more or less correct, depending on which scale is used, but is measured differently and will therefore give different results. Bone mass should not be confused with bone density. Bone mass therefore cannot say anything about osteoporosis.
What is visceral fat?
Visceral fat is the fat located between the organs and in the abdominal region. An increased amount of visceral fat occurs in people with an inactive lifestyle and unhealthy diet, and the term "thin-fat" describes precisely this scenario. A passive lifestyle and limited movement lead to an accumulation of fat in the abdominal region, which can lead to cardiovascular diseases, high blood pressure, and type 2 diabetes.
What is BMR (basal metabolic rate)?
BMR stands for basal metabolic rate and indicates the number of calories a person needs to consume to maintain their equilibrium. Even if you don't work out at the gym or go for a run, you burn calories – even when you sleep. This is why it's also important to get a good night's sleep. Poor and insufficient sleep can result in undesirable weight gain, and research shows that people crave unhealthy food more when they don't get enough sleep.
My body composition scale says I am 10 years older than I am – what does that mean?
If your metabolic age is higher, it indicates an unhealthy body composition. Metabolic age – or biological age – is calculated by taking into account body fat percentage, BMR, muscle mass, age, and gender. These figures are then compared to the healthy and ideal values for the mentioned factors. If your body fat percentage is too high compared to what is considered healthy for your gender and age group, your metabolic age will be higher than your actual age.
Why do some body composition scales measure differently?
There is, of course, a difference in measurements between a segmented body analysis and one that only measures through the feet. An example of this is Tanita BC545N and Tanita RD 953. These two scales use 2 different BIA frequencies when measuring.
If the physiological age fluctuates significantly, it may be due to 3 things:
- The same information and activity level were not entered.
- A physiological difference compared to the control group.
- A difference in intracellular/extracellular fluid.
Tanita body composition scales have an Athlete Function – what is it?
Tanita is the only brand that uses BIA and also has an athlete function. Serious athletes who use body composition scales with BIA meters often get results indicating they are overweight. This is because their overall physical level is outside the norm of what a body composition scale can measure. This usually gives a misleading result. When specifying one's activity level, up to 10 hours of exercise per week can be selected, but these 10 hours should only be seen as a guide. Some people will categorize themselves as athletic or athletically built without actually being so. The 10 hours of exercise per week should therefore be seen as a way to distinguish between people who believe they are athletically built and those who are athletes. The athlete function assumes that one is more muscular than average, and this is based on increased muscle mass and increased body water/fluid retention in the body.
Who can use the athlete function?
In fact, very few people fit into this category. Muscles are key, and if a person is more muscular than average, they should use the athlete function. There is also the group that doesn't have a large muscle mass but is very fit, such as runners who don't bulk up/want to gain muscle and weight. These should still use the athlete function, as it nevertheless gives a more accurate indication of their overall body composition.
Only a few people fall into the 'athlete' category, so a rule of thumb for most is not to use the athlete function. However, if you are very fit and active for 10 hours a week or more, you can use the athlete function. As long as the same information is entered each time, the measurements will be consistent and comparable.
When calculating body fat and other values, deviating and implausible results may occur in:
- Young people under 18 years of age
- Elite athletes and bodybuilders
- Pregnant women
- People with fever, undergoing dialysis, with fluid retention or osteoporosis
- People taking cardiovascular medication (for the heart and circulatory system)
- People taking vasodilating or vasoconstricting medications
- People with significant anatomical deviations in their legs relative to their total body height (significantly longer or shorter leg length).
