fat vs muscle differences, role, weight loss

Fat vs Muscle: The Ultimate Guide to Differences & Role in Weight Loss

Weight includes fat and lean body mass, which includes bones, bodily fluids, and muscle mass.

When many of us want to get healthier, many of us focus on the number on the scale, our weight.

Muscle mass includes the muscles that help us walk, run, lift things and engage in other voluntary movements.

It also includes the muscles that engage in involuntary movements, like our heart muscle and the muscles in our digestive tract.

In this article, we want to shed light on the importance of both fat and muscle, their differences, and how weight is only one aspect of health.

What are the differences between fat and muscle?

Compared in terms of physical size, muscle is heavier than fat.

Muscle is denser and heavier than fat. So, even if two individuals both have the same weight, say, 150 pounds, one could have a lean, toned physique with more muscle.


And the other could be chubby, with more body fat.

Related: How to Lose Weight Fast (Science-Backed Steps)

Fat takes up more space than muscle.

In connection to the previous point, since fat is less dense than muscle, it takes up more space.

When comparing one pound of fat with one pound of muscle, fat appears larger than muscle.

This is also why two individuals with the same weight can have very different physiques, one lean and the other, chubby.

Muscle burns energy and fat even while you are at rest.

Even when you are not engaging in any physical activity, your body needs the energy to keep the regular bodily processes like breathing and digestion going.

These involuntary activities require some movement in your muscles.

So the more muscle you have, the more energy and fat you will burn, just for your body to sustain itself, as stated in this study.

Muscle has more definition than fat.

Muscle gives your physique tone and definition.

While some amount of fat in the body is important, when it is too much, it covers your muscle, hiding your natural physique.

Muscle mass tends to decrease as we age, while fat does not.

During the aging process, it is normal for there to be a loss in muscle mass and muscle tone, as mentioned in this study. This is called sarcopenia.

While this happens, there is also a tendency for fat to increase because of a slowdown in our metabolism.

However, this can be minimized with regular strength-training exercises.

Muscle adds to strength and flexibility, fat does not.

The more muscles you have, or the stronger your muscles are, the more physical strength you have.

Too much fat, however, can impede physical strength and flexibility, as well as stamina.

Ideal amount of muscle vs fat mass 

Around 60% of body mass or weight is the weight of our muscles. When it comes to fat, ideal values are 6 to 17% in men and 14 to 24% in women, according to the American Council on Exercise.

What is the role of fat in the body?

Some amount of fat (name percentage for men and women) is an important component of the body. It has many purposes, namely:

1. Stores energy


The most basic function of fat is as a form of stored energy. From an evolutionary standpoint, fat is needed during periods of starvation, when food was difficult to obtain. 

In modern times, this does not happen often.

But when the levels of your blood sugar and carbohydrate stores in your liver run low, like during strenuous exercise, your body starts to use fat for energy.

2. Protects from injury

Fat is soft and present in all parts of our body, even around the organs. It serves as a cushion, a form of protection in case of trauma or injury.

Our brain is almost 60% fat, and this is why many of us tend to store fat in our stomach region as well, an area that has many vital organs. 

3. Helps store fat-soluble nutrients

Certain nutrients like vitamins A, D, E, and K are stored in the fat cells of the body and can be used when the supply is low.

Vitamin D, for example, primarily comes from exposure to sunlight. During winter, when there is less sunlight, the body uses up its stores.

4. Improves secretion of hormones

Fat tissue secretes certain hormones like adiponectin, leptin, and resistin, which have an essential role in fat and glucose metabolism.

When in balance, these hormones are important for the normal function of the human body.

However, in many obese individuals, larger amounts of these hormones are secreted.

Related: How to Lose Underarm Fat in 8 Easy Ways

What is the role of muscle in the body?

Muscle is a type of tissue that supports movement through contractions in muscle cells.

Whether the movement is voluntary and conscious like walking or running, or involuntary and unconscious like the examples listed below, muscles are there to support the movement.

Improves blood circulation

The heart is a muscle that is important for blood ciculation.

When it contracts, it pumps blood throughout the body, and when it relaxes, it fills up with blood to pump back out again.

Helps with digestion

Different muscles help with swallowing to the churning motion in our stomach organ, and pushing food through the small and large intestine.


Also, other muscles are required to help with the excretion of fecal matter, in the digestive tract support.

Because this movement is involuntary, it happens without us willing it, or even noticing it.

Supports childbirth

Childbirth is a feat of the muscles. During normal childbirth, the muscles of the uterus contract to push the baby out, and the muscles in the vagina stretch to accommodate the baby.

Enables urination

Every minute, our kidney filters our blood of waste like urea.

This excess waste, along with water, is sent to the urinary bladder, a muscle, which stretches to hold the urine. Once it has stretched enough, we get the urge to urinate.

Fat vs muscle: is muscle heavier than fat?

As mentioned previously, muscle is denser than fat, making it heavier, but taking up less space. Thus, one pound of muscle appears smaller and takes up less space than fat.

Can you lose fat without losing muscle?

Yes, definitely. When on a weight loss program, as long as you do strength-training exercises and eat at least ~0.8 to 1.2 g of protein for every kg you weigh daily, you will not lose muscle, only fat.

Does muscle increase weight?

It can. Muscle is heavy, so when you are trying to increase muscle mass, you might see the number on the scale go up.

Or, if you are on a weight loss program, it may not go down by much, because even if you are losing fat, you are also gaining muscle.

That is why it’s important not to focus on the number on the scale but your size.

What is the ideal fat vs muscle ratio?

So far, no clear guidelines have been given on the ideal muscle to fat ratio.


And since muscle mass is different from person to person, it is best to base your ideal weight on the guidelines for fat mass.

According to the American Coucil on Exercise, for adult women who are athletes or who are into fitness, body fat can range from 14 to 24%. For men, this figure is from 6 to 17%.

To calculate these values, you would need to have a device to calculate your lean body mass, so it is best to get an assessment from a fitness professional.

Related: How to Lose Weight Quickly for Your Wedding


While we have noted the differences between fat vs muscle.

And while muscle sounds like an all-around great thing, we hope you understand that both are equally important in the body, in the right proportions.

Fat need not be demonized – it Is also an essential component of our body that contributes to health as well as our physical appearance.

What’s important is to lead a balanced lifestyle, with a healthy diet and regular cardiovascular and strength-training exercise.