Signs You’re Losing Muscle

Muscles are something most people hope to gain, not lose. Unlike fat loss, losing muscle mass is rarely, if ever, on anyone’s list of fitness goals. However, even without the intention to lose or reduce muscle volume, sometimes people find that they’ve reduced their muscle mass.

So what could be the cause of this and are there any signs you can watch out for to catch this situation before it gets out of hand? Read on to learn more about signs you’re losing muscle, reasons why this may be happening, and much more.

What Are the Signs You’re Losing Muscle?

Here are some of the most common symptoms to watch out for in case you’re convinced that you are slowly losing muscle instead of fat:

How Do You Know If You’re Losing Muscle Instead of Fat?

• You’re Struggling at the Gym

Struggling at the gym is normal – after all, it’s not every day that you have the same energy levels or even enthusiasm to do and enjoy your workouts. 

However, if you realize that the workouts you used to do easily are becoming rather difficult or impossible to do, you may be experiencing some muscle loss.

If you can’t easily lift the weights you were previously used to or do as many sets or reps as before, this may be a clear indication that something is off with your muscles or your body in general.

• You’re Losing Weight Too Quickly

If weight loss has been your goal for the longest time and you suddenly realize that the scale is going down much faster than it usually does, you may want to put a pause on celebrating and consider if this is healthy. 

According to the CDC, healthy and sustainable weight loss equals a loss of 1 to 2 pounds (about 0.5 kg to 1 kg) a week (1). It may be considered slow progress by many, but it’s progress that ensures your health is safe and that you can keep the results long after you’ve achieved your goal weight.

Unfortunately, most of us aren’t patient and seek quick results. However, if you step on a scale and realize that you’re dropping pounds faster than what the CDC recommends, it may be a good idea to reconsider your weight loss strategy. This drastic change may be due to a sudden loss of muscle mass rather than fat loss, but could also be due to a number of different things. It’s important to reflect on this and potentially seek professional advice to make sure you’re staying healthy during your weight loss journey.

• You Feel Lethargic

In simpler terms, you feel weaker or more tired than normal. If you disregard weakness at the gym as a sign of muscle loss, then perhaps feeling weak while performing simple everyday activities could be the sign you need.

If you realize that you’re often sleepier than usual – even after getting enough sleep/rest – and become rather tired after doing the simplest tasks or chores, then you may take this as a sign that your muscles are in trouble.

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• You Look Less Muscular

This largely applies to people who had more muscle definition as the change would be more noticeable in them than in those with a higher fat percentage. Some ways to determine if you’re less muscular include:

1. Simply Looking at Yourself in the Mirror 

If you have a good understanding of what your body generally looks like, it can be easy to determine if you look less muscular than before.

2. Comparing New and Old Pictures 

Take a new picture and do a side-by-side comparison with an older picture of you. If your muscles look smaller than before or are less defined than they previously were, you may be experiencing some muscle loss.

3. Take Note of How Your Clothes Fit 

This is particularly easy with tight-fitting clothes. If these clothes that were tight before to show off your muscles now feel or look loose, this could be a clear sign of muscle loss.

• Your Body Composition Results Show No Fat Loss

This is perhaps the most sure-fire way to tell if you’re losing muscle or not. When it comes to weight loss vs fat loss, the best way to determine that you’re losing fat is by doing a body composition test (2).

There are different types of body composition tests to choose from, but all of them measure your body fat percentage, bone, water, and muscle in the body. Such tests are done by professionals to better determine your physical health and fitness (3).

As a body composition analysis is able to determine the percentage of body mass that’s fat compared to muscle (and even the areas in your body where fat is stored), you can use this test to see if you’ve been losing fat or not. The test can also tell you if your muscle has increased, decreased, or remained the same.

If your body fat percentage hasn’t changed, then this becomes a potential sign that you’re losing muscle and not fat. 

Check out this article on how to decrease body fat percentage so you can achieve those body goals you’ve been dreaming about. 

Read more: How Much Weight Can You Realistically Lose In A Month Without Compromising Health?

Why Am I Losing Muscle Mass and Weight?

Creating a calorie deficit of 500 to 750 calories a day is the main way to achieve consistent and healthy weight loss (4). Adding exercise on top of a healthy calorie-deficit diet would work to increase your total calories burned, which helps make a calorie deficit even easier compared to doing no exercise at all. Adding at least 30 minutes a day, three to five times a week, helps with calorie burning and muscle growth (5), which all lead to fat and weight loss (6).

That being said, it’s important to note that weight loss generally doesn’t go hand-in-hand with muscle loss. In fact, muscle loss isn’t something that is expected to happen in the process of shedding some extra pounds. If you realize that you’ve been losing both weight and muscle, here are some reasons why this may be happening.

What Are Some Reasons for Muscle Loss?

Above, we’ve seen the signs you’re losing muscle instead of fat, but what could be the root cause of these symptoms? Also known as muscle wasting or muscle atrophy, it’s a condition where your muscle mass decreases or withers away.

According to a review published in the Current Pharmaceutical Design journal in 2022, this loss/atrophy is categorized into three main groups (7):

• Physiologic Atrophy

This occurs when the muscles go without use for a long time. Physiologic atrophy is generally seen in bedridden people, but it can also be seen in people who lead a sedentary lifestyle.

A good example of physiologic atrophy can be seen in office workers who spend most of their days sitting down, thereby leading a largely sedentary lifestyle. In a study published in 2020, researchers found that these workers had musculoskeletal disorders largely in their upper bodies, specifically in their lower back, wrists/hands, and shoulders. Their lower bodies were less affected by this lifestyle but not by much – showing that muscle loss in the legs and buttocks can be caused by a sedentary lifestyle (8). 

Exercise is a great way to counter a sedentary lifestyle. Check out our 6-week workout routine for muscle mass to help you get more physically active and increase your muscle mass and strength.

• Pathologic Atrophy  

In this case, people experience muscle wasting when that specific part of the body loses stimuli. This specific type of atrophy happens due to aging, disease, severe infections, and even due to malnutrition.

Sarcopenia, aka age-related muscle loss, is a good example of pathologic atrophy. Our bodies start losing between 3 and 8% of muscle mass per decade after the age of 30. By the time we hit 60, this rate of decline is even higher. If nothing is done to mitigate this, then we continue to lose muscle and become weaker as the years and decades pass (9). This is one of the many reasons why strength training and exercise is incredibly important as you age.

Malnutrition (10, 11) – the lack of proper nutrition due to the failure to eat enough or not eating the proper foods – can also lead to muscle loss. To avoid this, it’s imperative to ensure you’re eating enough. Remember that a calorie deficit doesn’t mean starvation. 

You need to eat to lose weight and to keep your body functioning properly – just make sure to eat slightly fewer calories than your body burns daily. Don’t overdo the deficit.

• Neurogenic Atrophy 

This occurs when the nerves connecting your muscles are either injured, disrupted, or damaged. Research has found this type of muscle wasting to be evident in people who’ve suffered from a direct injury or disease of the peripheral nervous system, i.e. the brain or the spine (12). Treatment for this kind of muscle loss may require electronic stimulation, ultrasound therapy, or even surgery.

• A Combination of Any of the Above Factors  

Reviewers in a 2021 study review also stated that muscle loss can be due to a combination of multiple factors (7) and patients suffering from burns or illnesses such as cancer or arthritis may be forced to lead a sedentary lifestyle, which then leads to or worsens the wasting of muscle.  

What Are the Side Effects of Losing Muscle?

• Reduced Mobility

This is particularly true in older adults who may be suffering from sarcopenia. Research has shown that the less muscle older adults have, the less functionality they have, which reduces their mobility. This can make simple tasks such as walking or standing from a chair very hard (13, 14).

• Increased Risk of Fractures

Studies have shown that the loss of muscle mass and strength can lead to a higher risk of fractures, especially in older adults. These studies have warned that such fractures can also increase the risk of mortality in seniors (15, 16).

• May Negatively Impact Your Mental Health

Multiple studies over the years, specifically those done on older adults, have shown muscle atrophy to have an association with mental disorders, specifically anxiety and depression (17, 18, 19, 20).

• Reduced Quality of Life

The loss of mobility, reduced fitness, a high risk of fractures, and mental health issues caused by muscle atrophy will drastically reduce the quality of life of anyone who is affected by them (14).

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How to Lose Fat and Gain Muscle

Fat loss and muscle gain are possible, but it will only happen if both your diet and workout routine are up to par. Here are some things you should be doing to ensure that you only lose fat and build muscle:

• A Healthy Calorie Deficit

A calorie deficit helps your body burn more calories throughout the day, which helps with fat loss. However, as mentioned above, a calorie deficit that’s too large may lead to muscle loss as your body eats away at your muscles in search of energy. You should limit your calorie deficit to just 500 – 750 calories (4). 

Becoming aware of your basal metabolic rate (BMR) and the total calories you burn through exercise is the best way to ensure that you’re maintaining a healthy calorie deficit. With this deficit, you’ll still need to hit your BMR number in order for your body to function as it should. BMR is the amount of calories your body burns in a day without including any movement. This number doesn’t account for exercise or simple daily tasks you do throughout the day. 

• Eat More Protein

In terms of macronutrients for weight loss, protein stands above the rest. This macronutrient helps with weight loss through increased satiety, thermogenesis, and the maintenance and increase of muscle mass (21). High-protein diets are usually encouraged for weight loss. For the best fat loss and muscle gain results, try consuming 1.2 g to 1.6 g of protein per kg of your body weight per day (22, 23).

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• Sleep More

The average adult requires 7 to 9 hours of uninterrupted sleep each night, something that many of us fail to achieve. Studies have shown that failure to sleep enough negatively affects both weight loss and muscle gain, while adequate sleep positively affects both matters. Try your best to get at least 7 hours of uninterrupted sleep each night (24, 25, 26). 

• Exercise

Nothing boosts your fat loss and muscle gain goals more than working out. It helps you burn more calories and exercises, especially resistance training, help break down muscle which, with enough rest and protein intake, will repair itself allowing for the muscle to become bigger and stronger. Try working out 3 to 5 days a week for at least 30 minutes a day to get the best results (5).

Read more: I Want to Be Skinny: 6 Science-Backed Strategies for Fat Loss

4 Signs You’re Losing Fat and Not Muscle

Now that you know what to look for to see if you’re losing muscle instead of fat, let’s look at 4 signs to look for to answer the question ‘How do I know I’m losing fat not muscle?’

• Increase Confidence and a Sense of Well-Being

According to a study that was published in the Health Psychology journal, study subjects who lost weight reported fewer mental health troubles, in addition to increased feelings of vitality and self-control (27).

• Your Clothes Fit Differently

Fat and muscle fit differently within your body. The same amount of fat takes up more space than lean muscle. Once you start to lose fat while maintaining or building new lean muscle, your clothes will fit more comfortably or even start to become looser.

• Muscle Definition Becomes Apparent

While this will take some time to become truly visible, muscle definition will show itself as a sign you’re likely losing fat and not muscle. Maintaining your protein intake and keeping up with strength-training exercises will ensure you continue losing fat while preserving muscle mass.

• Reduced Body Fat Percentage

As previously mentioned, this is the best way to check if you’ve truly lost that extra fat and gained muscle. If you can, visit your doctor and have a composition test done before you start on your weight loss journey. When you get the test done again a few months later, you’ll be able to tell how much progress you’ve made in terms of fat loss and muscle gain.

Frequently Asked Questions

• How long does it take to lose noticeable muscle?

As with fat loss, gaining or losing muscle takes time before it becomes noticeable. This could be as little as a couple of weeks to several months.

• What does muscle loss feel like?

As previously mentioned, muscle loss often presents itself through reduced performance and feeling weak or lethargic. You may also have trouble walking, and maintaining your balance and may start to experience numbness in the affected area or limb.

• Will I lose muscle if I fast for 24 hours?

No, you won’t lose muscle or even fat after a 24-hour fast. However, you may become dehydrated if you don’t drink any water during the fast.

• Is it true that muscle turns to fat if you don’t exercise?

No, it’s not. In the same way that fat doesn’t turn into muscle, muscle won’t turn into fat when you stop exercising. Failure to work out reduces muscle mass, which makes them smaller. Less muscle mass can reduce your metabolic rate, which reduces calorie burning where less food is burned for energy and stored instead as fat in the body.

The Bottom Line

When it comes to signs you’re losing muscle, monitoring your performance in the gym, muscle size, and energy levels can help tell if this is happening or not. However, the best bet is to get a body composition test done as this will tell you the fat and muscle ratio in your body. You could also invest in a body composition scale, which can give you these values at home without needing to book a visit to your doctor.