Losing fat doesn’t automatically lead to muscle gain. When you’re losing weight, your body uses fat for energy. To maintain or build muscle, try to do regular strength training and eat more protein.

Trying to lose fat and build muscle is a common goal for many people.

Among the many fitness myths out there, one of the most popular is the idea that you can turn fat into muscle through weight training and a healthy lifestyle. However, the process of fat loss and muscle building isn’t quite that simple.

This article explains how to lose fat and build muscle in a healthy, sustainable way.

Share on Pinterest
Westend61/Getty Images

The simple answer is no. Turning fat into muscle is physiologically impossible, as muscle and fat are made up of different cells. A good analogy to this would be that you cannot turn a banana into an apple — they’re two separate things.

Muscle comes in three forms: skeletal, cardiac (heart), and smooth (mostly found in the intestine). The muscle most often thought of in regards to body composition is skeletal muscle, which is attached to bones by tendons and allows for voluntary movement of the body (1, 2).

Skeletal muscle tissue comprises bundles of muscle fibers known as myofibrils. Myofibrils contain smaller fibers that consist of long chains of amino acids, which are the building blocks of protein. Amino acids contain a unique nitrogen group in their chemical structure (1, 2, 3).

Contrarily, body fat — also known as adipose tissue — comprises triglycerides, which consist of a glycerol backbone and three fatty acid chains. Though various types of body fat exist, fat is exclusively made up of various carbon, hydrogen, and oxygen atoms (4, 5).

Since muscle and fat cells have different chemical makeups, neither can be converted into the other (6).


Since fat and muscle tissue have entirely different cellular makeups, you can’t turn fat into muscle or vice versa.

Weight loss is most often a combination of losing fat, muscle, and glycogen stores (water weight). Ideally, most weight loss should come from fat loss (7, 8).

To lose weight, you must achieve a calorie deficit by eating fewer calories than your body needs daily, increasing physical activity to burn calories, or a combination of both.

Yet, too large of a calorie deficit can lead to a rapid muscle mass loss, as the body will break down muscle to be used as an emergency fuel source. Thus, a moderate deficit of around 500 calories, or 10–20% of your total calorie needs per day, is recommended (8, 9, 10).

During a moderate calorie deficit, body fat is used as fuel to support the body’s regular functions.

Triglycerides stored in fat cells are broken down and sent to the mitochondria to produce adenosine triphosphate (ATP), which is the body’s main source of energy (11, 12).

Known as beta oxidation, this process produces carbon dioxide and water as byproducts. These are both exhaled during breathing and excreted via urine and sweat.

As such, when fat is burned, it’s not turned into muscle but rather broken down into usable energy (13, 14).

To preserve muscle mass during weight loss, it’s recommended to engage in strength training at least 2–3 times per week. Furthermore, eating a protein-rich diet has been shown to reduce muscle loss during a calorie deficit (9, 15).


During weight loss, fat is converted into usable energy and byproducts. To preserve muscle mass, it’s important to stick to a moderate calorie deficit, eat plenty of protein, and strength train a few times per week.

If you’re looking to lose fat and build muscle, here’s how you can do it in a healthy, sustainable way.

To lose fat, the body must be in a calorie deficit. You can achieve a calorie deficit by increasing your physical activity, eating fewer calories, or a combination of both. A modest increase in physical activity and decrease in calorie intake is most sustainable (16, 17).

Consuming mostly minimally processed, whole foods rich in fiber, healthy fats, and protein will help you achieve a calorie deficit without feeling deprived or hungry (16, 17).

Furthermore, it’s best to incorporate both cardiovascular and strength training, such as lifting weights, using resistance bands, or Pilates, 5–7 days per week (16, 17).

Examples of moderate intensity cardio include walking, running, or biking for over 20 minutes while still being able to talk with limited struggle.

Meanwhile, strength training helps preserve and build muscle and can increase the body’s metabolic rate for upwards of 72 hours. This means that even after a good strength training session, your body will still burn extra calories (18, 19).

What’s more, muscle is more metabolically active than fat, meaning having more muscle on your body can further support weight loss by burning more calories (20, 21).

Thus, combining these two forms of exercise along with a minimally processed, whole food diet will support the body in achieving a calorie deficit.

If you’re trying to build muscle and lose fat at the same time, it’s important to engage in strength training. Strength training combined with a high protein diet helps build new muscle cells through a process known as muscle protein synthesis.

Most experts recommend at least 2–3 strength training sessions per week that target multiple muscle groups, along with adequate rest days to allow for muscle rebuilding (22).

Muscle is built from a diet high in dietary nitrogen, mostly found in protein-rich foods. Protein from food is broken down and converted into amino acids to support muscle building (23, 24, 25).

To maintain muscle during weight loss, be sure to eat enough protein and avoid a large calorie deficit. Most people should aim to get 0.6–0.9 grams of protein per pound (1.4–2.0 grams per kg) of body weight daily, or around 20–40 grams of protein per meal (15, 25, 26, 27).


Sustainable fat loss while preserving muscle includes eating at a moderate calorie deficit, consuming adequate protein, and engaging in both cardio (aerobic) exercise and strength training 5–7 days per week.

It’s a myth that you can turn fat into muscle.

During weight loss, fat is taken from fat cells and used to produce energy in the body along with other byproducts. Ideally, muscle is preserved through strength training and consuming a protein-rich diet.

For sustainable, long-lasting weight loss, try to incorporate both cardio and strength training into your routine at least 5–7 days per week and eat a diet comprising mostly whole, minimally processed foods.

While losing weight and gaining muscle requires dedication, the good news is that with a little effort, the body will adjust accordingly.