Tri Talk Nutrition Calculator
beta version 0.8
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The Tri Talk Nutrition Calculator (TTNC) is designed to give athletes a baseline strategy for race-day nutrition. While nothing replaces race nutrition simulation while training, or pure years of experience, the intent of the TTNC is to give the athlete a starting point to begin experimenting with different caloric intake amounts. Thereby reducing the number of errors in the unavoidable trial and error process of nutrition strategies. The calculator uses fitness, intensity, distance, weight, and use of fat vs. glycogen to calculate an approximate amount of total calories required for the event.
Please note that every athlete's stomach can tolerate a diverse amount of calories per hour. Also, it has been noted by several listeners that many theories hold that the human body can only absorb (oxidize) up to 360 calories per hour. However, current research indicates that the type of carbohydrate consumed can increase this oxidation by and absorbtion to over 500 calories per hour. This is discussed in Tri Talk Episode 49.
A detailed discussion on the theory behind the Tri Talk Nutrition Calculator can be heard in Tri Talk Episode 45. I very much would like to hear your feedback on the TTNC to improve the formulas.
    = Input required  
    = Automatic calculation based on input
Enter your weight in pounds   pounds  
Select your estimated fitness level    
High < 12% body fat  
Medium > 12% <20%  
Low >20%  
Females add 6% to guidelines  
Total estimated glycogen stores:   calories  
Override estimate (optional)    
Select event type    
Enter estimated race intensity   %  
As % of Max Heart Rate  
Zone 2 (Ironman) 75-82%  
Zone 3 (Half-Ironman, Marathon) 82-87%  
Zone 4 (Sprint, Olympic) 87-90%  
Zone 5 (Sprint) 90%+  
Estimated race intensity as % of VO2max   %  
    Actual Suggested
  Minutes Hours Minutes Hours
Swim Time  
Bike Time  
Run Time  
Total Time  
    Actual Suggested  
Swim calories burned    
Bike calories burned    
Run calories burned    
  Please ensure you adjust your actual calories burned above!  
Estimated total calories burned    
Estimated % of calories burned from fat    
Required calories from glycogen    
Add some calorie "insurance"    
Total calories required    
 Total calories required minus initial glycogen stores    
Hours on bike and run    
Required Calories per hour    
Formulas used in the Tri Talk Nutrition Calculator
  Formula Where…  
Base calculation = C(h)=(G-(EE(R)+I))/Dh C(h) = Calories per hour  
      G = Initial glycogen levels  
      EE = Energy expenditure  
      R = Fat to carbohydrate ratio  
      I = Calorie "insurance"  
      Dh = Event duration in hours  
Estimated glycogen stores = W(FR)   W = Weight    
      FR = Fitness level ratio  
      High =    
      Medium =    
      Low =    
Estimated race intensity as % of VO2max = (%MHR-37)/0.64 %MHR = % of Max Heart Rate  
Baseline race time performance, medium fitness =   Minutes   Total Minutes
    Swim Bike Run Total Hours
  Half Ironman 39 180 105
  Ironman 78 360 240
  Marathon 0 0 210
  Olympic 30 68 45
  Sprint 15 34 21  
Baseline race time performance fitness multiplier = BL(FR)   BL = Baseline medium fitness performance  
      FR = Fitness level ratio  
      High = 0.90    
      Medium = 1.00    
      Low = 1.15    
Estimated total calories burned = (W/SM)(ST/60)(IM)(%VO2) W = Weight    
  +   (S,B,R)M = Swim, Bike, or Run multiplier
  (W/SM)(ST/60)(IM)(%VO2) Swim =    
  +   Bike =    
  (W/RM)(RT/60)(IM)(%VO2) Run =    
      (S,B,R)T = Swim, Bike, or Run time  
      IM = Intensity multiplier  
      Multiplier =    
      %VO2 = Intensity as a % of VO2max
Estimated % of calories burned from fat = (1-(%VO2/100))(FR)+.03 %VO2 = Intensity as a % of VO2max  
      FR = Fitness level ratio  
      High =    
      Medium = 1.00    
      Low = 1.05    

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