Nutrition Science for Triathletes
In order to demystify some of the crazy eating and dieting in our Multisport world the following can be very helpful in determining how much we eat during training and also determining what mix of food types we should be considering.
Basal Energy Needs (BEE) = Calorie needs at rest
To calculate for an adult triathlete who trains 1-2 hours per day at 60% of V02 max. Multiply your weight in kilograms by 40-50 calories. This will give you the calories needed for the BEE and energy expenditure during your workout.
My weight = 158 lbs / 2.2 kilograms = my weight in kilograms or 78.81 kg x 45 calories = 3231 calories. (if you are more sedentary on a given day multiply by 40 and if you are more active use 50)
Next you need to add the calories for SDA. (Specific Dynamic Action, these are calories used for food metabolism) To calculate, take the total calories from your BEE and multiply the total by 10%. Therefore, 3231 BEE calories x 10% = 323 calories. Add the two together gives you your total calories for the day!
= 3554 calories!
Why is this so important?
Besides giving you the energy needed for doing the given activity, your body needs the calories to repair and even do such daily maintenance tasks such as keeping you warm, breathing, and digesting. If you are not getting in ample calories during the day and keeping up with it, you wind up in calorie debt before you go to bed. Then you wake up hungry and eating the entire fridge. Not good because your choices and cravings during that time are so strong that it is easy to make bad choices. (candy bars, cookies, and cake become our main choice of fuel!) The next day things don’t go so well because we loaded up on sugar the night before and feeling guilty get into the habit of not eating enough for our next routine and series of workouts. This can create a bad cycle of under eating and overeating and subsequently impact your performance and health.
Food as fuel should be generally broken down as follows
Carbohydrates = 50-75% (could be more on longer bike days) Simple sugars should be no more than 10% of these calories.
Protein = 1.4 kilograms x your body weight. (for me that would be 78.81 kg x 1.4 = 110 grams
Fat = less than 30% of your total calories = (ex: for me that would be 3554 x 30% = 1066 calories or less. To calculate grams divide those calories 1066 / 9 calories per gram of fat = 118)
Saturated Fat = less than 10% (ex: for me that is 323 calories)
As you can see there is quite a lot of consuming going on here. The key is to be proactive and keep balance in your diet. If you have harder and longer days be sure to increase these guidelines and if you have easier days (i.e. you were just sitting on a sofa all day long) this would be only 2000 calories. As always this is a guideline and you may need to adjust your diet to be more specific to you.
All the best,
Reference ~ Lisa Dorfman MS, RD, LMHC 99,