Although most exercise programs promote building muscle, some people may be interested in losing muscle mass.

For example, these people may:

  • feel that their muscles are giving them a ‘bulky’ look
  • feel that their bodies are aesthetically out of balance and want to trim down specific parts
  • wish to slim down while maintaining strength
  • want clothing to look a certain way on their bodies
  • feel that larger muscles tend to sag as they exit middle age

In this article, we’ll review how muscles are grown and the best ways to lose muscle mass.

Healthline does not endorse or recommend losing muscle mass as it is not a healthy goal for most people. However, we do believe in providing accessible and accurate information to reduce the harm that can occur if people choose to do so. Before beginning any exercise program, it’s a good idea to consult with a doctor to make sure you stay within limits that are appropriate for your age, sex, and physical condition.

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To understand how to lose muscle mass, you have to understand how to make muscles grow.

Muscle growth, or hypertrophy, is typically pursued by a consistent weightlifting program combined with a high calorie, high protein dietary program.

In an intensive anaerobic weightlifting workout, muscle fibers are damaged and then repair themselves during rest periods. When the rate of repair is faster than the damage, muscle growth occurs.

Your body fuels your workout and recovery with calories from food.

To lose muscle mass, you must reduce your caloric intake and alter your workouts.

Consider these adjustments:

  1. Diet. Consume fewer calories and eat a lower percentage of foods that are high in proteins and carbohydrates.
  2. Weight training. If you’re continuing to train with weights, use lighter weights and reduce weight training frequency to no more than 2 times per week to maintain tone.
  3. Cardio. Focus your workouts on long periods of cardiovascular exercise, known as marathon cardio, to burn calories.

To build muscle in your arms and legs, you:

  • lift to failure
  • increase the number of reps
  • increase the speed of your lifting
  • reduce rest time between sets
  • eat a high calorie, high protein diet

Thus, to lose muscle in your arms and legs, do the opposite:

  • stop a few reps before failure
  • reduce the number of reps
  • rest for full recovery (2 to 3 minutes) between sets

You should also consider long periods of cardio such as:

To lose mass, consider a deficit diet — lowering the number of calories you eat in a day to below the number of calories you burn in a day.

According to the Centers for Disease Control and Prevention (CDC), a healthy diet includes:

  • vegetables, fruit, whole grains, and fat-free or low fat dairy products
  • lean meats, fish, poultry, eggs, nuts, and beans
  • minimal added sugars, salt, cholesterol, saturated fats, and trans fats

An alternative (but not recommended) way to lose muscle mass

If you stop working out and eat a diet that gives you fewer calories than you burn, you will lose muscle mass. This is NOT recommended.

You will also lose strength and cardio fitness.

  • A 2013 study indicated that it takes about 3 weeks for athletes to start to lose muscle strength if they stop working out.
  • A 2018 study indicated that when athletes majorly cut back their cardiovascular exercise schedule, their cardio fitness dropped significantly after 4 weeks.
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You can reduce your muscle mass by basically doing the opposite of what you would do to increase muscle mass.

Whatever your reason for losing muscle mass on purpose, it’s important to do it safely.

Before setting a goal for your body and changing your exercise routine and diet, consult a doctor to make sure that you stay within limits that are appropriate for your age, sex, and physical condition.