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Fuel

Determining energy sources for endurance athletes has been a hot topic of debate.  Contradictory evidence and advertising claims lend much to the confusion.  In order to establish a dietary plan of attack so as to properly fuel training, one first needs to settle upon a dietary school of thought.  Whether  60-10-30,  40-30-30, or some other ratio of  carbs : protein : fat  is used, the key is finding what works for you.  Perhaps the best starting point is a review of the three principal energy sources and how each contributes.

1 gram of carbohydrate = 4 calories   1 gram of protein = 4 calories   1 gram of fat = 9 calories

Now armed with the proportional formula of choice and knowing how much each fuel adds, the next step is to find caloric needs as a function of activity level, to determine how much and what type of foods to consume.  The calculator below illustrates  simple caloric needs based upon body weight and training duration.  It calculates grams of energy source utilizing a   57 : 13 : 30    ratio of   carbs : protein : fat.  Keep in mind that this is an overly simplified model and that many other factors can enter into the ultimate equation.

 

Calorie Calculator

Weight

  

Hours training
     
Basic Requirements  cal   Carbohydrates gm
Training  Requirements  cal   Protein gm
Total  Requirements  cal   Fat gm

Using 160 lbs and 1 hour training as an example generates the following :

2887   Total calories derived from  :   411 gm carbs    94 gm  protein    96 gm fat

As an athlete's body becomes fitter and an ever-efficient "furnace," as it were, the ratios can be adjusted.  For example, long slow distance training usually adapts the body to metabolize fat cells more proficiently.  Intense anaerobic activity recruits easily burnt carbohydrates.  So a fine tuning process evolves as conditioning changes.

 

           Key Concepts

  1. Protein requires additional digestion time.

  2. Carbohydrates are stored as glycogen.

  3. When glycogen stores are full, excess carbs get stored as fat cells.

  4. When carbs and glycogen are depleted the body may cannibalize muscle protein.

  5. The body stores carbs and glycogen for roughly 2 hours of aerobic activity.

  6. The body's potential energy reserve in fat cells is bountiful at 9 cal / gm.

 

Applying these tools to one's diet requires a bit of time and effort.  Most packaged food has the nutrient information labeled.  Fresh foods may require a kitchen scale and chart.  After going through the full range of your normal diet a couple of times, you get a sense for where the numbers add up and it becomes much more intuitive.