Muscle Weight vs. Fat Weight: Frequently Asked Questions

Starting on a weight loss journey isn’t easy and it’s normal to get fixated on tracking calories and the number on the scale. Many 8fitters report that they see differences in their body composition, strength and energy, but are disappointed to see the same — or sometimes higher — number on the scale.

Why might this be? The simple answer is that when it comes to muscle weight vs. fat weight, muscle weighs more. Muscle, by nature, is denser and takes up less volume than fat. Our best advice won’t come as a surprise: stick with your meal plan, do regular workouts, and focus less on the scale and more on how you look and feel.

In this article, our 8fit coaches answer your most frequently asked questions about muscle weight and fat weight.

Does muscle increase weight?

Yes. If you gain muscle, you’ll gain weight. This is even true for individuals who shed fat while increasing their strength. Remember that the number on the scale doesn’t tell the whole story. 8fit’s primary workout program consists of strength-building, fat-burning HIIT workouts. As you progress through your individualized workout program, you’ll notice your strength increases as your waistline decreases.

How much does muscle weigh?

This is a question 8fitters often ask. What’s more important to understand here is that muscle is denser than fat. So, one cubic inch of muscle weighs slightly more than one cubic inch of fat. Depending on a number of individual factors, muscle weighs about 15-20% more than fat.

Does muscle weigh more than fat?

One pound of muscle and one pound of fat weigh the same: one pound. The difference is the amount of space they both take up. Like we mentioned above, one cubic inch of muscle weighs more than one cubic inch of fat. But, why? We’ll answer that in the next question.

Muscle vs. fat density: Which one is more dense?

Why does muscle weigh more than fat? It all has to do with density and overall composition. Muscles are made of long fibers tightly woven together. Fat, on the other hand, is composed of different sized droplets and some are more full than others. These droplets stick to each other but leave some empty space in between.

In the image below, you’ll notice that one pound of muscle takes up less space than one pound of fat. This is why you might notice a slimmer waistline but no drastic change on the scale as you begin a new workout or meal plan regime – your body is burning light fat, but building heavier muscles.

Muscle vs Fat Density weight

What’s the difference between a muscle weight vs. fat weight calculator?

There are a number of ways to calculate body composition, but not every method is easily accessible to everyone. First, some of these tests are quite expensive and also only available at hospitals or special labs. Some of these body composition calculator methods include:

  • Skin calipers: These devices measure the thickness of skin folds in different areas of the body. The devices are relatively inexpensive, but the margin for error is high because the same areas must be pinched time after time. This test is reliable but needs to be performed by a health professional or kinesiologist.
  • Bioelectrical impedance: Bioelectrical impedance monitors send small electrical pulses throughout the body and measure how quickly those impulses return — fast return time means more muscle tissue, less fat and a leaner physique. These monitors are affordable, but not always accurate because of variables like hydration levels, meal times and more.
  • Hydrostatic weighing: Hydrostatic weighing submerges your body in water and calculates the difference between your normal weight and weight under water. While this is an accurate technique, it’s not easy to find a proper hydrostatic weighing facility.
  • Dual-energy X-ray absorptiometry (DXA): DXA scans can calculate bone density and body composition. Like hydrostatic weighing, this method is extremely accurate, but you might have a hard time finding a facility. You’ll need to book an appointment with a medical professional and pay a pretty penny or two.

Other ways to calculate muscle weight and fat weight include 3D body scans, measurement of total body water and air-displacement plethysmography.

What is the ideal muscle to fat ratio?

To answer this question, we need to know a little more about you. Your ideal muscle to fat ratio depends on your gender, age bracket, activity level and more. Here is the breakdown according to the American Council on Exercise (ACE):

WomenMen
Essential fat10-13%2-5%
Athletes14-20%6-13%
Fit individuals21-24%14-17%
Acceptable25-31%18-24%
Obese>32%>25%

What contributes to the number on the scale?

There’s a lot more than muscle and fat weight contributing to the number you see on the scale. Your bones and organs weigh a bit too. Then, there’s water weight. The adult human body is around 60% water and the number on the scale can fluctuate depending on how hydrated you are.

If you have specific questions about your ideal weight or body fat percentage, consult your primary care physician. For workouts and healthy recipes that help you reach your goals, sign up for 8fit.