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In this episode, we explore how a dedicated endurance athlete builds a nutrition plan from scratch. We cover calculating calorie and macro requirements, fasting, hydration, and fueling strategies to optimize performance and recovery. In this episode, Shara Perry, RDN and endurance athlete Brance Baca-White discuss optimal nutrition, hydration, and training strategies, emphasizing personalized approaches and scientific insights to improve performance and health.
Use these calculations as starting points, then adjust based on body-weight trends, performance, hunger, recovery, sleep, and training quality.
1. Estimate BMR
Mifflin-St Jeor
Men:
BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5
Women:
BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161
Conversions:
lb ÷ 2.205 = kg
inches × 2.54 = cm
2. Estimate TDEE
TDEE = BMR × Activity Factor
1.2 = Sedentary
1.375 = Lightly active
1.55 = Moderately active
1.725 = Very active
1.9 = Extremely active
For high-volume endurance athletes, approximately 1.725–1.9 may be an appropriate starting range.
3. Set Protein
~1 g protein per lb of desired body weight
Example: 185 lb goal = 185 g protein/day
Protein = 4 calories/g
4. Set Fat
~0.25–0.4 g fat per lb body weight
Fat = 9 calories/g
Example: 196 lb = approximately 49–78 g/day
5. Calculate Carbohydrates
Carb calories = Total calories − protein calories − fat calories
Carb grams = Carb calories ÷ 4
Example at 3,400 calories:
185 g protein = 740 calories
55 g fat = 495 calories
Remaining = 2,165 calories
Carbohydrate = ~541 g/day
6. Pre-Workout Fuel
For easy/short sessions, some athletes may tolerate minimal fueling.
For long or hard sessions, prioritize carbohydrate.
A simple starting point:
20–40 g carbohydrate before an early workout
Choose foods that are high-carb, relatively low-fat, relatively low-fiber, and easy to digest.
7. During the Run
For sessions lasting more than ~1 hour:
30–60 g carbohydrate/hour
For longer marathon-specific sessions:
60–90 g/hour may be appropriate for highly trained athletes who have practiced and can tolerate it.
8. Post-Workout
25–40 g protein + substantial carbohydrate
Prioritize recovery nutrition after long or demanding sessions, particularly when another hard workout is coming soon.
9. Baseline Hydration
A practical starting estimate for baseline daily fluid intake is:
Body weight (lb) × 0.5–0.67 = ounces of fluid/day
This is your baseline before accounting for significant exercise losses.
10. Calculate Sweat Rate
Record:
- Pre-exercise body weight
- Post-exercise body weight
- Fluid consumed
- Urine produced
- Exercise duration
Fluid loss = weight loss + fluid consumed − urine produced
Sweat rate = fluid loss ÷ exercise duration
Repeat under different training and environmental conditions for a better estimate.
11. Post-Exercise Fluid Replacement
For more rapid recovery:
~16–24 oz fluid per pound of body weight lost
This is particularly useful when another significant workout is coming soon.
12. Sodium
There isn't a well-established evidence-based body-weight formula for baseline sodium needs in healthy adults. The National Academies specifically set an adult sodium Adequate Intake at 1,500 mg/day, but they also note that this does not adequately address people with large sweat losses, such as competitive athletes. They could not establish a higher universal requirement for high-intensity athletes.
During endurance training:
~300–600+ mg sodium/hour
Individual sodium needs vary. Sweat sodium testing can provide a more personalized target.
The Takeaway
These calculations are starting points, not magic numbers.
Calculate, implement, monitor your response, and adjust based on body weight, performance, hunger, recovery, sleep, and training quality.
Support the show
Work with me at Nourish (covered by insurance, often $0): https://signup.nourish.com/providers/shara-perry?referralSource=Nourish+dietitian&referralName=Shara+Perry&utm_source=Nourish_dietitian&utm_term=Shara_Perry
