Whether you want to lose weight, bodybuilding, or train to stay healthy, knowing your lean mass helps you reach your goals and keep your health in check. Lean mass equals your weight when you subtract the pounds of fat (the percentage of body fat). In general, you should try to keep your lean mass unchanged when you lose weight, so that you only lose the pounds of fat. To calculate this and track your fitness progress, you can start by measuring your body fat percentage. Other methods of estimating or determining lean mass vary in accuracy and accessibility, so choose the best option for you. Keeping your lean mass unchanged also helps you have strong bones and bring your fat levels to healthy values, which preserve brain and organ functions.
Steps
Method 1 of 2: Apply Calculations and Measurements
Step 1. Calculate your lean mass using height and weight
While this isn't a perfect measurement, you can estimate your body fat percentage with a simple formula. Substitute "W" for your weight in kilos and "H" for your height in centimeters in the following equation to get your lean mass (in kilos):
- Men: Lean Mass = (0, 32810 × W) + (0, 33929 × H) - 29, 5336
- Women: Lean mass = (0.29569 × W) + (0.41813 × H) - 43.2933
- Note: 1lb = 0.453592kg, and 1in = 2.54cm.
- To make it easier, use an online calculator like this one.
Step 2. Calculate Lean Mass from Body Fat Percentage
Use one of the techniques described below to get your body fat percentage. Divide the percentage by 100 to make it a decimal number, then multiply it by your total weight. For example, if you weigh 100 kg and have calculated that your fat percentage is 20%, multiply 100 x 0.2. This gives you the fat in kilos (100 x 0.2 = 20 kg). Subtract that figure from your total weight to get lean mass; in this case, 100 - 20 = 80 kg of lean mass!
It doesn't matter which unit of measurement you use to calculate your weight, since you will use the same unit for all calculations
Step 3. Measure your body fat percentage with a skin fold assessment
An experienced professional can estimate your fat percentage by squeezing three, four or seven different parts of your body and measuring the thickness of the skin folds with a caliper. You can calculate your fat percentage from those measurements using a shape or conversion table. This is a relatively inexpensive option, but the results aren't always accurate.
Some personal trainers and physical therapists are able to perform this measurement. Find an experienced professional who does it often; ask for advice at the gym
Method 2 of 2: Leveraging Technology
Step 1. Use a biolelectric impedance balance
You may have seen one in the gym or in your personal trainer's office. These scales have electrodes that send very mild electrical signals into your body when you step on them, so you can measure your body fat percentage (fat and muscle conduct electricity differently). They are safe and completely painless. Just step on the scale barefoot and follow the instructions.
- Some scales directly indicate lean mass, but most simply determine your body fat percentage.
- You can buy one of these scales and use it at home to measure body fat over time.
- This is an easy method to use, but it is not always accurate.
Step 2. Try a hydrostatic balance
A hydrostatic or underwater balance compares your weight on land to your weight when you are completely submerged in water; an experienced technician can use these values to calculate your body fat percentage. This is a very precise method, but it costs 40-60 € on average. Find a lab or clinic that is capable of weighing you underwater in your area.
A "bod pod" (or air displacement plethysmography machine) is similar to a hydrostatic balance, but uses air instead of water. This is a very accurate test for people with close to average BMIs, but less accurate for those who are very thin. Do your research to find such a machine in your area
Step 3. Undergo a DEXA bone densitometry
A DEXA scanner (from English Dual-Energy X-ray Absorptiometry) is used as an X-ray machine: it is a harmless and very precise procedure, but probably expensive. It is usually used to measure bone density and check for osteoporosis. This is a very accurate method, but it must be done by a doctor who is experienced in this type of procedure. It can also be very expensive. Talk to your doctor for more information.
