Your metabolism involves a set of processes that all living things use to maintain their bodies. These processes include both anabolism and catabolism. Both help organize molecules by freeing and capturing energy to keep the body running strong. These phases of metabolism happen simultaneously.

Anabolism centers around growth and building — the organization of molecules. In this process, small, simple molecules are built up into larger, more complex ones. An example of anabolism is gluconeogenesis. This is when the liver and kidneys produce glucose from noncarbohydrate sources.

Catabolism is what happens when you digest food and the molecules break down in the body for use as energy. Large, complex molecules in the body are broken down into smaller, simple ones. An example of catabolism is glycolysis. This process is almost the reverse of gluconeogenesis.

Understanding anabolism and catabolism can help you train more effectively to lose fat and gain muscle. Rest is also a part of the equation. Your metabolism is at work even when you’re sleeping.

Your hormones play an important role in these processes. Different hormones in the body are associated with either anabolism and catabolism.

Anabolism involves the hormones:

  • estrogen
  • insulin
  • growth hormone
  • testosterone

Catabolism involves the hormones:

  • adrenaline
  • cortisol
  • cytokines
  • glucagon

Any disruption to your hormones, like thyroid conditions, may also affect these processes and your overall metabolism. For example, a small study on bodybuilders examined their hormonal anabolic-catabolic balance as they prepared for competition. Some of the men continued training and eating as usual, while others were energy-restricted to reduce their body fat.

The energy-restricted group saw significant decreases in their body fat and muscle mass compared to the control. Their insulin and growth hormone levels also decreased throughout the duration of the study. Testosterone levels, too, decreased between 11 and 5 weeks before competition. In other words, the men’s “anabolic pathways” were compromised, even in those who were taking in high protein.

The researchers concluded that the bodybuilders may need to employ other nutritional strategies to prevent a catabolic breakdown effect before competition.

Since anabolism and catabolism are parts of your metabolism, these processes affect your body weight. Remember: When you’re in an anabolic state, you’re building and maintaining your muscle mass. When you’re in a catabolic state, you’re breaking down or losing overall mass, both fat and muscle.

You may be able to manipulate your body weight by understanding these processes and your overall metabolism. Both the anabolic and catabolic process lead to fat loss over time. With regard to your weight on the bathroom scale as a benchmark, however, things can get a bit tricky.

  • If you do a lot of anabolic workouts, you’ll tend to shed fat and maintain or even gain muscle. Muscle is more dense than fat, so your body weight and body mass index may stay higher despite a leaner physique.
  • Catabolic workouts, on the other hand, may help you shed pounds by working off both fat and muscle. You’ll weigh less, but you’ll also have far less critical muscle mass.

You can think of these processes as an equation to predict whether or not you may lose or gain weight.

Take catabolism (how much energy your body produces) and subtract anabolism (how much energy your body uses). If you produce more than you use, you may pack on pounds as the energy gets stored away as fat. If you use more than you produce, the opposite may happen.

There are exceptions, of course, especially if you have underlying medical conditions that affect your hormones.

Working your body in different ways can produce different results. Cardio and strength training are each associated with different metabolic processes. Here’s how to get the most out of your workouts, depending on your goals.


Catabolic exercises are aerobic, or cardio, exercises. They may include moves — like running, swimming, and biking — where you’re in a steady active state for a relatively long period of time. According to the American College of Sports Medicine, aim to get at least the following amounts of aerobic exercise each week:

  • 150 minutes of moderate intensity, or
  • 75 minutes of vigorous intensity

This is usually broken down into three to five days of training. If you have a history of health conditions, check in with your doctor to get the OK before starting this regimen.

Your heart rate, blood pressure, and respiration all rise during catabolic exercise. The body breaks down glycogen during your sweat sessions to use as fuel. When you run out of carbohydrate stores, your body’s cortisol uses amino acids to create energy.

As a result, catabolic exercises may help you build a healthy heart and lungs. But they may also cause you to lose body mass, both muscle and fat. It effectively breaks down muscle over time. Some of this muscle may be rebuilt during sleep or rest of eight hours or more through spontaneous anabolic processes.


If you’re looking to build muscle, being in a catabolic state for too long can work against you. It can decrease your muscle mass and even compromise your overall health. Preventing catabolism is all about keeping good balance between your nutrition, training, and recovery.

Muscle can be maintained by training three or four days a week. The following sample exercise program may help you stay in a building or anabolic state. Try focusing on one area per day, resting in between.

Muscle groupsExercise
chest, abdominals• incline barbell bench press
• flat dumbbell bench press
• cable crossovers
• crunches (3 sets of 25 reps)
quadriceps, hamstrings, calves• leg extensions barbell squats
• incline leg presses
• dumbbell lunges
• standing leg curls
• lying leg curls
• standing machine calf raises
back, biceps, and abdominals• wide-grip pullup (3 sets of 10 reps)
• close-grip lat pulldown
• bent-over barbell row
• barbell deadlift
• hanging leg raise (3 sets of 25 reps)
shoulders, triceps•seated dumbbell shoulder press
• standing dumbbell lateral raise
• reverse fly
• dumbbell shrug
• triceps pushdown
• lying triceps extension

Unless otherwise noted, perform each exercise in 3 sets of 15 repetitions, working down to 12 and then 8 repetitions. Overall, to stay in an anabolic state and maintain your muscle mass, you must train this way regularly.

Working together

You can also do exercises that are a blend of both anabolic and catabolic. A well-rounded exercise program should include both aerobic and strength training. Sprinting and other high-intensity interval training (HIIT) are good examples. In this sort of training, your body is working hard on both cardiovascular endurance and strength. The result is building muscle and losing fat.

Researchers examined this idea by having participants run 250-meters four times on a treadmill at 80 percent of their maximum capacity for speed. They rested three minutes between sprints. Their results showed changes in the anabolic-catabolic balance of hormones. Testosterone, for example, increased significantly, showing the involvement of the anabolic process.

Anabolism requires energy to grow and build. Catabolism uses energy to break down. These metabolic processes work together in all living organisms to do things like produce energy and repair cells.

Understanding the difference between anabolic and catabolic processes may help you reach your goals in the gym and on the scale. Whatever you’re looking to achieve, regular exercise — cardio and strength training — plus a diet rich in whole foods can help you stay healthy on the inside and out.