Muscle catabolism refers to the breakdown of muscle proteins into smaller molecules, releasing energy and leading to a reduction in muscle mass. This process is a natural part of metabolism but becomes concerning when muscle degradation outpaces synthesis, resulting in muscle wasting.

Muscle catabolism can be triggered by intense physical activity (specifically overtraining without adequate rest/refuel), severe stress, trauma, hormonal imbalances, aging, & inadequate levels of nutrition (protein specifically). 

Protein plays a vital role in several functions within the body. Development of skeletal muscle, repairing of cells, & overall health maintenance. Let’s take a look at the primary reasons as to why protein is of high importance:

Building blocks: You may have learned prior (or maybe not) that proteins are compromised of amino acids. These amino acids are the “building blocks” of cells, tissues, & organs. 

Proper immune function: The right amount of protein intake can help create antibodies. Better off this way when it comes to fighting infections. Why would you not want to boost your immune system?

Hormones + Enzymes: Necessary for production of enzymes. These enzymes aid in digestion, as well as regulation of hormones. These hormones help regulate growth, as well as our metabolism.

Transportation process: Proteins like hemoglobin are extremely important. Hemoglobin transports oxygen into the blood. Other proteins can move nutrient & waste from the blood. 

The process of repairing muscle: Strenuous activity like resistance training causes damage at the physiological level. As these fibers are damaged, proteins aid in repairing these fibers through the process of recovery. This will lead to larger & stronger fibers. 

Hypertrophy stimulation: Protein provides protein synthesis triggering amino acids like leucine. This is how fibers grow!!!!

Prevent the loss of skeletal muscle: This is simple. Eat more protein, especially while in a deficit. This is when processes like catabolism commonly kick in. Protein is a great source of energy. It is not only used for energy, but is a great way to promote fullness & aid in weight management. 

WHY does insufficient protein intake cause destruction to our body? The answer is, CATABOLISM 🚫

Without sufficient levels of protein intake, your body can enter the catabolic state. What happens?:

• The breakdown of muscle tissue
• When energy is required, the body demands. If protein is insufficient, energy from amino acids will be required. Hence, the breakdown of muscle tissue. 
• Critical functions like repairing cells & muscle fibers, producing enzymes, & supporting the immune system will all be affected. 
• Most common during caloric deficits, the lack or deficiency of protein is detrimental. The body may require using muscle protein as a source of energy when glycogen storages are depleted. 

Why is catabolism bad long term?

• The continuous breakdown of muscle protein will slow your metabolic rate. This will lead to a decrease in strength & mass. 
• Harder to lose weight or maintain weight. 
• Crappy recovery from exercise. Performance reduced, risk of injury increased.

So, bottom line. If you train hard, or train at all… Especially @ high intensities, ensure your body is refueled with the proper amount of protein intake daily. 

1.6-2.2kg per lb. Of body weight is the standard. I recommend different intake structures dependent on goals, current state (deficit or surplus), experience level, training regimen, etc. 

I would try to ensure that you eat 1g of protein per Lb. daily. So if I weigh 187lbs., I’m eating 187g of protein daily. This is different per subject, but this can be a very effective way to ensure you have sufficient protein. I do not recommend this high of intake for beginners until they are acclimated to their new lifestyle. 

Supporting peer reviewed articles:

1. Insufficient protein intake can prompt the body to break down muscle tissue to meet its amino acid requirements, particularly during calorie deficits or malnutrition. academic.oup.com
2. Engaging in prolonged or high-intensity exercise without proper recovery can trigger muscle catabolism. wsj.com
3. Studies have shown that stress hormones cause catabolism of muscle proteins, thereby decreasing muscle strength. pmc.ncbi.nlm.nih.gov
4. Research indicates that chronic stress and associated hormones affect skeletal muscle mitochondrial functions, leading to muscle atrophy. link.springer.com
5. Factors contributing to sarcopenia include inflammation, impaired protein synthesis, physical inactivity, and endocrine changes. journals.physiology.org
6. Insufficient dietary protein can result in muscle protein breakdown, as the body lacks the necessary amino acids for maintenance and growth. cambridge.org
7. Overtraining, characterized by excessive exercise without adequate rest, can lead to a maladaptive response resulting in muscle protein breakdown. pmc.ncbi.nlm.nih.gov

Don’t be catabolic… Be anabolic!