Body Fat Percentage vs Muscle Mass: Which Should You Track?

When it comes to tracking fitness progress, two numbers often dominate the conversation: body fat percentage and muscle mass. Both measurements provide useful information but answer different questions.

Body fat percentage shows how much of your current body weight is made up of fat, while muscle mass gives you an indication of how much muscle tissue you carry. Neither is inherently more important than the other.

The more useful question isn’t which measurement is better but whether the changes you’re seeing support your current goals.

Why Body Weight Alone Can Be Misleading

Your body weight includes fat, muscle, bone, water, and other tissues.

This means the number on the scale may change even when your body fat hasn’t changed significantly. Your weight may also stay the same while you lose fat and gain muscle.

For example, you may notice:

• Your weight remains stable, but your clothes fit differently
• Your weight fluctuates even though you’re “doing everything right”
• Your strength improves even though your weight doesn’t change

Therefore, tracking body composition provides more context than body weight alone. Instead of only checking if your weight has gone up or down, you can start asking what has actually changed.

Body Fat Percentage Range

Your result should be considered alongside factors such as:

• Your age and sex
• Your sport
• Your training history
• Your current training phase
• Your energy levels and recovery
• The method used to measure body composition

Recent research involving over 600 athletes across 18 competitive sports found considerable variation in body-fat levels, and importantly noted that whether the lowest observed levels represent “healthy” thresholds remains unclear. PubMed

Body fat percentage should therefore be considered as context, not a score you need to chase.

The more useful question is: “Does your current body composition support your training, recovery and performance goals?”

What Should You Focus On?

The answer ultimately depends on what you’re training for.

For example, a HYROX athlete needs enough strength and muscle to manage the stations while maintaining the aerobic fitness and running efficiency required across the race, while a distance runner may need to balance strength development against the energy cost of carrying additional body weight.

So rather than aiming for a particular body-fat percentage or muscle-mass number because it appears “ideal”, it helps to understand what those numbers mean in the context of your body, sport and training.

And that requires looking beyond body composition alone.

Body Composition Testing at FORGED by RF: VisBody and Resting Metabolic Rates

At FORGED by RF, body composition testing isn’t simply about receiving a percentage and placing yourself into a category.

The testing process follows three steps:

1. Assess your current body, movement or performance
2. Analyse what the results mean for your training
3. Apply the findings through practical recommendations and programming

VisBody 3D Scan

The VisBody 3D Scan can help establish an objective body-composition baseline with body fat percentages and muscle mass measurements.

Additionally, the scan provides additional information about your body, including posture, body circumferences and shoulder mobility.

That means the assessment can help you look at not just how much fat or muscle you carry, but also other measurable characteristics of your body that may be relevant to your training and progress.

It may be useful if you’re:

• Starting a fat-loss programme
• Beginning a muscle-building phase
• Tracking body recomposition
• Monitoring progress across a training block
• Looking beyond body weight alone

Rather than reacting to a single percentage, you can use repeated scans to understand how your body composition is changing over time.

For example, a stable body weight may look disappointing on the scale. However, your scan may show that you’ve reduced fat while maintaining or increasing muscle. Changes in body circumference may provide another useful indication that your programme is having an effect.

This gives you a more complete view of whether your programme is producing the intended result.

Resting Metabolic Rate Test (RMR)

Body composition tells us more about what your body is made up of. The next question is how much energy that body needs.

Your Resting Metabolic Rate, or RMR, is the amount of energy your body uses at rest to maintain essential functions such as breathing, circulation and temperature regulation.

It can also provide information such as your respiratory quotient (RQ), which gives additional context around the mix of fuels your body is using during the test.

An RMR Test may add useful context if you’re:

• Planning a structured fat-loss phase
• Trying to gain muscle
• Increasing your training volume
• Unsure whether general calorie estimates suit you
• Looking for a measured resting-energy baseline
• Interested in understanding your resting fuel utilisation

Combining body composition information with an RMR measurement can provide a more individualised starting point for nutrition planning than relying solely on scale weight and standard calorie equations.

Rather than relying on a single number, combining different measurements allows you to build a more complete picture.

When to Retest?

Once you have a baseline, the next step is giving your programme enough time to produce a meaningful change.

For many people, retesting after approximately 8 to 12 weeks of consistent training and nutrition provides enough time to identify a more meaningful trend.

However, the right timeline depends on your starting point, programme and goal.

Where possible, complete each scan under similar conditions. Try to use the same testing method, test at a similar time and follow the preparation guidance provided by the FORGED by RF team. The aim is to understand whether the direction of change supports what you’re trying to achieve.

Conclusion

So, when comparing body fat percentage vs muscle mass, the answer isn’t one or the other. Track the measurement that matters for your goal — and, in many cases, track both.

If you’re trying to lose fat, you want to know whether fat mass is decreasing without unnecessarily sacrificing muscle. If you’re trying to build muscle, you want to know whether the additional weight you’re gaining is actually contributing to lean mass. And if performance is your priority, both measurements need to be interpreted within the demands of your sport.

Most importantly, neither number exists in isolation.

Together, they provide the clearest picture of health, performance, and long‑term resilience.

Contact our team via WhatsApp for help choosing the right assessment.