Fit Food: Metabolism

Fire-Up-Your-Metabolism-2-620wSo far on Fit Food we’ve talked a lot about what, when, why and how much food we should be eating. But what happens to that food within our bodies? The process by which food and drink calories are converted into energy to be used by our bodies is called metabolism. You don’t need to become an expert in physiology or biochemistry, but it does help to have a basic understanding of how that banana fuels your workout and how that bag of chips becomes love handles.

Our bodies have two metabolic states; anabolism or “building” and catabolism or “breaking down”. Anabolism occurs through a series of chemical reactions that synthesizes new molecules from smaller particles. This process requires energy. An example is the rebuilding of muscle tissue after a workout. Catabolism occurs when the body breaks down molecules to release energy which is used for many different functions, from cellular processes to body movement. An example would be the breakdown of stored glycogen to supply energy to working muscles during weight lifting.

Let’s take our example of a banana and follow it as it goes from a fitness buff’s favourite fruit to fueling your next workout. Digestion starts in the mouth as you chew your food to break it down. As it travels through the stomach and the rest of the digestive system, enzymes release vitamins and minerals and further break down carbohydrates, fats, and proteins into their component parts which then pass through the small intestine walls into the bloodstream. Once in the bloodstream these particles are carried around the body to where they are needed. So far, this process has been catabolic. Our bodies must first break down the food we eat before it can be used to fuel bodily processes and build new tissue.

Now that we have nutrients floating around our bloodstream, the body can use these particles in cablecurlsanabolic processes. Some of the digested carbohydrate from our banana will be used for energy immediately and some will be shuttled to our glycogen stores within the liver and muscle, to be called upon the next time we need a quick burst of energy. If we ate our banana with a protein source after a workout, the amino acids from the digested protein molecules would be delivered to damaged muscle tissue to begin the rebuilding process. Perhaps you had some peanut butter in that post workout shake? Those fats would be broken down into fatty acids which would be used to build cell membranes and fight inflammation.

Now that our muscles and cells have been built up and our energy stores replenished, we are ready to work out! As you start to exercise, your metabolism flips to catabolic as it breaks down glycogen (remember that banana?) and other stored fuel sources to meet increased energy demands. The minor muscle damage that occurs as part of a progressive strength training program is also catabolic, but it’s necessary to break down the muscle tissue in order for it to be rebuilt stronger. Once your workout is finished and you eat your post workout meal (within the 45 minute “anabolic window”) the influx of needed nutrients will help to flip your metabolism back to anabolic to repair and replenish your muscles and energy stores so you can come back stronger and with even more energy next time!

Although catabolism is often thought of as “bad” you can actually see that it is a necessary part of the process. The way your body looks, how much muscle you have and how lean you are, is a balance between anabolism and catabolism. If you were only ever anabolic, meaning never exercising and regularly feeding your body beyond its needs, then you will be in a building phase most of the time. Those excess nutrients need to go somewhere and since you aren’t giving your body the stimulus it needs to build muscle or cause other beneficial adaptations like stronger cardiac muscles or increased endurance, you only build your fat stores.

Likewise, being catabolic most of the time is not good either. “5-forgotten-fat-loss-tips_eStarvation” diets or large amounts of cardio with inadequate refueling will result in your body catabolizing whatever it can to get the nutrients it needs. If you cut your calories too low your metabolism will actually respond by slowing down to match your consumption and storing every bit of food it does get. Since it’s impossible to keep up with such little food for long, eventually the dieter returns to normal eating and often actually binge eats following a period of restrictive calorie cutting. Now you have an influx of nutrients and a severely depressed metabolism that cannot possibly handle the excess it is now receiving. Since the body has been primed to store fat it now does just that, rapidly filling your fat stores and creating new fat storage when those are full. This is why crash dieters often regain all of the weight they lost and then some.

Your best strategy for a strong, healthy, fit and lean body is a balance between catabolism and anabolism. We need periods of catabolism to provide energy for our bodies and to supply the necessary stimulus for physical adaptations to exercise, like muscle growth and greater cardiovascular endurance. Catabolism also helps us burn off excess fat, provided we are fueling our bodies properly over the course of the day and meeting our caloric needs. Anabolism allows us to build strong muscles and repair injuries, replenish energy stores and otherwise prepare the body for it’s next challenge. It’s this constant cycle of breaking down and building back up over the course of months and years that will create a lean, athletic physique!

Happy Lifting!

This article was researched and written by

All the information contained within these World Wide Web Pages is Copyright

8 comments for “Fit Food: Metabolism

  1. May 30, 2013 at 5:39 am

    It’s interesting to see it broken down like this. For the most part I just make sure I get my macros and micros but never give much thought beyond that. Thanks for the knowledgeable perspective Dara!

    • daracoxpt
      July 3, 2013 at 5:10 pm

      The body is incredibly complex and every little bit you can understand about how it works will help in your training!

  2. Saliema
    May 28, 2013 at 1:18 pm

    Wow, I didn’t know half of this info.
    Thanks for sharing.

    • daracoxpt
      July 3, 2013 at 5:08 pm

      Hi Saliema! Thanks for reading, I’m glad I could share some new info with you!

  3. Andrew
    May 27, 2013 at 9:16 am

    I hadn’t ever thought of training as being catabolic but I guess it is. Great points you make in this post.

    • daracoxpt
      July 3, 2013 at 5:08 pm

      Thanks Andrew! Catabolism isn’t always a bad thing! The important thing is to properly regulate the two states according to your goals. Thanks for reading!

  4. Michael Harris
    May 26, 2013 at 10:37 am

    This is a great post. You put it so simply for people. I think this is a very important perspective when it comes to dieters (particularly calorie counters). Food isn’t just an energy source – it’s matter. A collection of molecules that can be deconstructed and reconstructed to build body tissue. So much talk goes straight to caloric content and skips completely over the need to build and replenish the body itself.

    Thanks for sharing!

    • daracoxpt
      May 26, 2013 at 7:55 pm

      Hi Michael! Thanks for reading, I’m glad you enjoyed it!

Leave a Reply