Your Analysis


You need energy to do a race. You get the energy from stored protein, fat and carbohydrates.
You start out with some stored energy, then during the race your body uses that stored energy.
If you are doing a long enough activity (several hours) your stored energy may not be enough and you may bonk out ("hit the wall").
So during the race you consume food and drinks that contain carbohydrates in an effort to replenish the calories your body uses.
It's like a game: you start out with some calories. Then during the race your body uses up calories while you try to eat and drink more calories in an effort to keep up with your body and avoid a deficit.
This web site has been designed to help you plan your nutrition strategy.

The Facts

If you eat well on the day before your race your body converts your food to glycogen and stores the equivalent of between 1600 and 2400 calories in your liver and muscles.
The following factors influence how much your body can store:
  • The fitter you are, the more you can store.
  • The lower your body fat percentage is, the more you can store.
  • The more you weigh the more you can store.
Here's a reasonable article on the subject of stored calories

So you have somewhere between 1600-2400 initial calories before the start of the race.
As you are racing your body consumes energy from your fat and carbohydrates that you eat/drink and have stored.
The more you weigh the more calories you burn.
The total amount of energy your body consumes, as well as what percentage of it comes from calories of carbohydrates, is related to your intensity.
The higher the intensity, the more energy/calories your body uses.
A portion of the total calories your body uses comes from fat and another portion comes from carbohydrates. The ratio of the carbohydrates calories to fat calories that your body uses increases as you increase your intensity.
Your heart rate, as a percentage of your maximuum heart rate (MHR), is a measure of your intensity.

Example: if a certain person is running at 65% of MHR he may be burning 330 calories per hour. 35% of it may be coming from carbohydrates (we're not concerned with fat calories).
If, however, this person is running at 80% of MHR he may be burning 600 calories per hour, but a whopping 80% of it may be coming from carbohydrates.

The Planning & Analysis does the following for you:
  1. It helps you estimate your initial stored carbohydrates calories based on your fitness level.
  2. It calculates the total calories needed to be performing the various activities, based on your body weight, and the duration and intensity that you specify for each activity. Total calories include fat, carbs, and protein.
  3. It then calculates how much of the total calories will come from carbohydrates (Since we are not concerned with fat and protein) for each activity, based on the intensity of the activity
  4. It calculates and shows you your "Shortage" which is the amount you start out with minus the amount of calories from carbohydrates that are needed to complete all the activities at the intensities you specified. So for example, if you start out with 2000 calories, and will use up 400, 1500 and 2000 calories of carbohydrates during your swimming, cycling, and running, respectively, the total carbohydrates calories that your body will use is 3900. So your "Shortage" will be 1900 calories of carbs (3900 minus 2000).
  5. It then calculates the total amount of carbohydrates you are planning to take in during the race by eating and drinking. This is calculated based on your specification of the amount of calories in each unit of the stuff you eat and drink, and the number of units of each type.
  6. Once it knows how much calories of carbohydrates you will be consuming and how much you will be taking in, it calculates and shows you your balance at the end of each activity. In other words, the balance at the end of your swim is your initial calories minus the calories of carbohydrates that you lose during the swim plus the calories you take in during the swim. Your balance at the end of the cycling is your balance at the end of the swim minus the calories of carbohydrates that you lose during the cycling plus the carbohydrates calories you take in while cycling, and so on for the run.
  7. It calculates and shows you your final balance or deficit. If it's a deficit, you can try to minimize if by either (1) decreasing your planned intensity (which results in less calories being consumed, and even more importantly, a greater portion of the total calories will come from fat and not from carbohydrates) or (2) eating or drinking more food/drink items that contribute calories of carbs.
  8. It also calculates and displays your planned average calories per hour for each activity. Note that there is some concensus that consuming more than about 300 calories per hour is an unattainable goal for most athletes.
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