What Does Body Fat Percentage Mean?
Body fat percentage is the proportion of your body weight that consists of fat. If you weigh 70 kg and your estimated fat mass is 14 kg, your body fat percentage is 20%. BMI is calculated from height and weight, so it cannot distinguish between fat and muscle. Body fat percentage is also not a number that can determine your health on its own; it should be considered alongside waist circumference, blood pressure, and blood test results.
Why It Is Difficult to Define One Normal Range
Body fat percentage varies depending on age, sex, and measurement method. Do not use ranges designed for athletes as general health standards, or determine whether you have obesity based on a single reading from a home device. If your level is very low or has changed suddenly and you experience symptoms such as menstrual changes, fatigue, or dizziness, consult a healthcare professional.
Every Measurement Method Has Some Error
Home scales and InBody devices estimate body composition using bioelectrical impedance analysis (BIA). Results can vary depending on hydration, recent meals, and exercise. DXA measures bones and soft tissue together, but it is not a perfect standard either, and its cost and radiation exposure should be considered. Skinfold measurements are affected by the examiner's skill. With any method, it is better to compare trends using the same device under similar conditions.
Standards to Follow When Tracking Changes
Keep the measurement time and your eating and exercise conditions as consistent as possible, and look at the trend over several weeks rather than small daily fluctuations. Recording your weight, waist circumference, and exercise results as well can help you avoid fixating on a single number. Results from a home calculator are for reference, not a diagnosis.
If You Need to Lose Weight, Start Slowly
The CDC advises that gradual weight loss of about 1–2 pounds (approximately 0.45–0.9 kg) per week is easier to maintain than rapid weight loss. Eat meals that include vegetables, whole grains, and protein foods, and gradually increase walking and strength training to match your current fitness level. There is no need to drastically reduce your intake or eliminate a particular nutrient.
When Professional Guidance Should Come First
If you are pregnant or breastfeeding, an adolescent who is still growing, have a history of an eating disorder, or are being treated for kidney, liver, or metabolic disease, it is safer to consult a healthcare professional before starting a weight-loss plan. Do not start medication or supplements based solely on a body fat percentage calculation.