UNDERSTANDING YOUR MEASUREMENTS
Body composition analysis complements weight and body mass index with data on fat mass, fat-free mass, body water, muscle mass and their distribution.
Understanding what these different measurements represent allows the sports or health professional to better interpret the body profile, adapt their recommendations and precisely track the patient's progress over time. For the client, this data helps to better understand the changes in their body and to measure progress that is not always visible on a standard scale.
Body composition refers to how body weight is distributed among its different components, in particular fat mass, muscle mass, body water and the other tissues that make up fat-free mass. Unlike weight or BMI, which provide overall information, body composition analysis makes it possible to understand what really makes up the kilos shown on the scale.
A body composition analysis provides around a dozen measurements, each representing a body component or region. Results vary by sex and age, and every fact sheet details the reference values for women and for men.
Fat mass is the total amount of adipose tissue present in the body, expressed in kilograms or as a percentage of weight. The S580 provides fat mass, body fat percentage and a segmental fat analysis. It is the key indicator for checking that weight loss is genuinely fat loss.
Fact sheet coming soonFat-free mass brings together all the components of the body that are not fat : muscle, water, bone, organs and other tissues. The HowBody report includes lean mass, muscle mass, skeletal muscle mass and the segmental analysis of dry mass.
Fact sheet coming soonMuscle mass is the total mass of the body's muscle tissue, mainly the skeletal muscles that enable movement. Tracking it makes it possible to assess how the musculature changes, for example during a training programme, weight loss or a fitness programme. Depending on the device, it can also be analysed by body region in order to observe its distribution.
Fact sheet coming soonSkeletal muscle mass corresponds to the muscles attached to the bones, directly involved in movement and maintaining posture. Tracking it makes it possible to measure changes in the musculature more precisely, for example as part of a sports programme, weight loss or support related to ageing.
Fact sheet coming soonBone mass is an estimate of the amount of matter that makes up the bones. It contributes to total fat-free mass and varies in particular according to body type, age and sex. It should not be confused with bone mineral density, which requires a specific medical examination called bone densitometry (DXA).
Fact sheet coming soonBody water is divided between intracellular water, contained inside the cells, and extracellular water, found in particular in the blood and the spaces between cells. Analysing them separately makes it possible to obtain a more precise reading of hydration and of how fluids are distributed throughout the body. HowBody devices can distinguish intracellular water from extracellular water and provide information on their balance.
Fact sheet coming soonProtein is part of fat-free mass and is mainly found in the muscles and other tissues. Estimating it rounds out the body composition assessment and provides additional information about the body's active tissues.
Fact sheet coming soonMinerals are the mineral elements present in the body. A large part is linked to the bone structure, but they are also found in the body's tissues and fluids. This data complements the assessment of fat-free mass, without replacing a medical measurement of bone mineral density. HowBody devices present protein and inorganic salts in their body composition report.
Fact sheet coming soonPhase angle is an indicator that helps assess the quality and condition of the body's cells. It is obtained through bioelectrical impedance analysis, by examining the way the electrical current passes through tissues and cell membranes. This measurement must always be interpreted according to the person's age, sex and profile.
Fact sheet coming soonVisceral fat is the fat located deep in the abdomen, around the internal organs. It differs from subcutaneous fat, which lies under the skin. Thanks to its calculation model, HowBody can provide this data to assess a person's metabolic profile.
Fact sheet coming soonBasal metabolic rate is the minimum amount of energy the body expends at rest to carry out its vital functions, such as breathing, maintaining its temperature or keeping its organs working. It is generally expressed in kilocalories per day and estimated from several body metrics. In other words, it is an estimate of the energy expenditure the body needs to function at rest. Interpreting it requires taking into account activity, the goal and the individual context.
Fact sheet coming soonDaily calorie intake is an estimate of daily energy needs, calculated from the basal metabolic rate and, depending on the method used, the level of physical activity. It gives an order of magnitude of the number of calories needed each day to cover energy expenditure.
Fact sheet coming soonMetabolic age puts the basal metabolic rate and body composition into perspective against reference values associated with different ages. It provides an indicator that is easy to track over time, but it corresponds neither to actual biological age nor to a medical diagnosis.
Fact sheet coming soonBody mass index (BMI) relates weight to height using the formula weight (kg) / height² (m). It provides a quick way to gauge body size, but it does not distinguish between fat and muscle. This is why body composition analysis offers a far more detailed reading. HowBody provides data on these 2 indicators during a body analysis.
Fact sheet coming soonThe waist-to-hip ratio compares the circumference of the waist with that of the hips. It helps assess how mass is distributed around the abdomen and complements the other body composition indicators for tracking changes in body shape over time.
Fact sheet coming soonSegmental analysis examines different parts of the body separately, usually the right arm, the left arm, the trunk and both legs. It makes it possible to observe the distribution of muscle mass and/or fat mass and to identify any asymmetries more easily.
Fact sheet coming soonPerforming a body composition analysis can be useful for weight monitoring combined with nutritional support, a fitness goal, optimising athletic performance, or preventing illness and the effects of ageing.
Body composition analysis makes it possible to check whether a change in weight actually corresponds to a loss of fat mass, of muscle mass or to a variation in body water. As part of nutritional support, it thus helps to set more precise goals than simply losing kilos and to adjust the programme so as to encourage a reduction in fat mass while preserving muscle mass.
Fat loss, not muscle. The scale alone doesn't tell you that.
In athletes, body composition makes it possible to track changes in muscle mass and fat mass according to performance goals. A segmental analysis can also compare the distribution of muscle between the arms, the legs and the trunk. Taken regularly, these measurements make it possible to assess the effects of training and to adjust the programme accordingly.
Muscle tracked by segment. Arms, legs, trunk.
Body composition analysis can highlight certain indicators associated with the risk of metabolic diseases, in particular excess fat mass or visceral fat. This information provides a view that complements weight and BMI and can be monitored as part of a prevention approach. However, it replaces neither a medical assessment nor the examinations used to diagnose a condition.
Visceral fat under watch. A benchmark to complement BMI.
With age, body composition changes, notably with a tendency for muscle mass to decrease and fat mass to increase. Measuring these parameters regularly makes it possible to track these changes and to adjust physical activity and diet in order to help maintain muscle mass, mobility and independence.
Muscle mass maintained. Mobility and independence over time.
A body composition analysis generally relies on bioelectrical impedance analysis (BIA) and the 3D body scan. BIA analyses the electrical properties of tissues to estimate fat mass, muscle mass or body water, while the 3D scan measures the body’s shape, volumes and circumferences.
BIA measures the resistance of tissues to the passage of a very low-intensity, imperceptible electrical current. Tissues rich in water and electrolytes, such as muscle, conduct the current better than adipose tissue. The measured impedance then makes it possible to estimate different body compartments thanks to the device's calculation models.
The current is transmitted by electrodes in contact with the body, usually at the feet and, on the most comprehensive professional devices, at the hands as well. An eight-electrode system can perform a segmental analysis in order to study the arms, the legs and the trunk separately.
The 3D scan complements BIA by producing a three-dimensional representation of the body from optical sensors. It makes it possible to precisely measure the circumferences and volumes of different areas, such as the waist, the hips, the arms or the thighs, and to visualise how they change over time. Unlike BIA, it mainly analyses external body shape rather than the internal composition of tissues.
The measured electrical values are then combined with data such as height, weight, age and sex depending on the method and device used. Calculation models then make it possible to estimate fat mass, muscle mass, body water and other indicators. It is therefore important to distinguish directly measured data, such as impedance and weight, from body composition values, which are generally estimated.
The right method depends on the goal, the context and the level of precision required. Weight, BMI, impedance analysis, the 3D scan and DXA do not produce the same information. Comparing them must focus on the data they actually provide and on the limitations specific to each technique.
| Method | Main data | Professional value | Point to watch |
|---|---|---|---|
| Weight and BMI | Weight relative to height | Simple, quick benchmark | Does not distinguish tissues or their distribution |
| Impedance analysis | Body water, fat-free mass, fat mass and derived indicators | Quick measurement, well suited to monitoring | Results depend on the protocol and equations used |
| 3D scan | Circumferences, volumes, body shape and avatar | Visual reading and body-shape comparison | Analyses the body's surface, not the internal tissues |
| DXA | Fat mass, lean mass and bone mineral content | Precise clinical analysis of the compartments | Requires medical access, cost and exposure to low-level radiation |
A body composition analyser is a device that makes it possible to assess the body’s different components beyond weight alone. Professional models generally use bioelectrical impedance analysis (BIA) to estimate, in particular, fat mass, muscle mass and body water. Some systems such as HowBody combine this technology with a 3D scan in order to also analyse measurements, volumes and body shape.
The results of a body composition analysis should be interpreted as a whole and, above all, tracked over time. A single, isolated value for fat mass, muscle mass or body water provides limited information: the value lies in putting it into perspective with the person’s profile, their goals, the device’s reference values and the change observed between several measurements.
Body composition depends on sex, age, body type and level of physical activity. In adults, body fat percentage is one of the main indicators: as a rough guide, it is often around 10 to 20% in men and 18 to 28% in women, with values that can differ in athletes and change with age. Interpreting a good body composition therefore rests on the balance between fat mass, muscle mass and other body compartments, as well as on how they change over time.
A body composition assessment is the full set of measurements and indicators obtained during a body analysis, together with their interpretation. It can present, among other things, weight, fat mass, muscle mass, body water, visceral fat and their distribution. Repeated at regular intervals, it makes it possible to compare results and to precisely track the person’s progress.