Q&A: Does Cardio Diminish Muscle Mass? How Many Calories A Day Should I Be Eating?


The common idea among gym-goers is that cardio training – or running on a treadmill, ruins your gains, and can diminish muscle mass. Is this true or just another urban gym myth? 


In this week’s edition of Q&A we answer the all-important fitness and nutrition questions – does cardio training deminish muscle mass, and how many calories should you be eating in a day? 


Let’s get started. 


Q: Does Cardio Diminish Muscle Mass?

A: This one is not so simple to breakdown. 


Before you understand if cardio breaks down muscle mass you need to understand how muscle is built in the first place. 


How to Build Muscle

When you workout you create small microtears in the muscle – especially if you are training for hypertrophy. After a training session you rest, consume good foods and recover – this is when muscle growth occurs. 


After weeks and weeks of training with high-quality and consistency you develop sustainable muscle growth. 


The question is then – why would cardio make any difference and make you lose muscle mass? 


Typically speaking, cardiovascular training does not necessarily build muscle. The action of running or biking does not actually isolate a muscle in the same way weight training would.


This does not mean that you cannot build muscle or that cardio training diminishes muscle. 


With that said it is important to note that cardio training is vitally important to your success as an athlete or someone who is trying to improve their health. 


So – what’s to blame for a loss in muscle mass? 

  1. Poor Nutrition intake
  2. Not enough calories while training
  3. Lack of protein in the diet 
  4. A drastic increase in metabolism


To conclude…


Cardio training does not lead to a loss in muscle mass. 


When you start to increase the amount of cardio training you are doing you should consider that you will need to increase the number of calories you are consuming and ensure that the food you are consuming is as complete as possible. 


Q: How Many Calories a Day Should I Be Eating? 

A: The total number of calories you should be intaking is highly dependant on a variety of factors like: 

  • how old you are
  • how often you train
  • what your goals are and many more 


The average person who is trying to lose weight can use a very simple calculation to figure out how many calories they are consuming on a daily basis. 


Bodyweight (pounds) x 12 = maintain weight

(Note: this can fluctuate from 12-15 depending on the individual)


Bodyweight (pounds) x 10 = lose weight

(Note: this can fluctuate from 10-12 depending on the individual)


For example – if you are 200 pounds and want to lose weight you would be consuming about 2000 calories a day. 


It is also important to consider your overall requirements for macronutrients. 


You should try to focus the majority of your diet on whole foods like fruit, vegetables, lean protein sources and minimize the amount of fat you are consuming. 


Athletes have a little bit of a different approach and should be strict on the nutrients they are consuming. 


Protein requirements can be calculated by using 1g/pound of body weight (on the high end). Overall calories should be about bodyweight x 15. 


This means if you weigh 200 pounds you should try to consume about 200g of protein and consume around 3000 calories a day to build muscle. 


Athletes who are in a building phase should not be worried about overall caloric limits. Eat as much as you need as long as the calories are from whole foods and fresh. 


With all this said, sometimes weight loss isn’t an exact do this for success – science. A lot of people will do well to record their dietary intake for a week or so and start to make adjustments in total calories and food intake (with the help of a professional).

The weight loss experience and total caloric intake is completely unique to each individual. 


To summarize – the average person should try to consume around 2000 calories a day from whole foods that are as unprocessed as possible. 


Keep the questions coming and as always feel free to comment below. Enjoy the training.