Athletes & Active People

Nutrition strategies for those who train regularly and want to optimize performance and recovery.

📖 The Story

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Sarah ran 40 miles per week and ate "clean"—mostly salads, grilled chicken, and vegetables. She was always tired, her pace had plateaued, and she kept getting minor injuries. Her doctor couldn't find anything wrong.

A sports dietitian solved the mystery in one session: Sarah was eating like a sedentary person while training like an athlete. Her "clean" 1,800 calories couldn't support her 2,800-calorie expenditure. She was chronically underfueled.

"But I'm not trying to lose weight," Sarah protested.

"Your body doesn't know that. It just knows it's not getting enough fuel. So it's conserving energy, suppressing recovery, and breaking down slowly."

Within six weeks of properly fueling—2,600 calories with strategic carb timing—Sarah hit a PR, her energy returned, and her nagging injuries resolved.

The lesson: Training breaks you down. Nutrition builds you back up. Skip the nutrition, and you stay broken down.

On the opposite end, Mark lifted weights 4x/week and ate 4,000 calories daily of "bulking food"—fast food, mass gainers, whatever had calories. He gained weight, but most of it was fat. His performance suffered under the extra mass.

When he dialed in his nutrition—same calories, but from quality sources with proper protein distribution—he maintained weight but improved body composition. His strength went up while his body fat went down.

The lesson: Quantity matters, but so does quality and timing.

🚶 The Journey

How Nutrition Supports Training Adaptation

The Training-Nutrition Cycle:

Phase 1: Training (Catabolic)

Muscle fibers damaged
Glycogen depleted
Hormonal stress response
This is intentional—stress drives adaptation

Phase 2: Immediate Post-Training (0-2 hours)

Highest muscle protein synthesis potential
Glycogen replenishment fastest
Protein + carbs most effective
"Anabolic window" exists but isn't as narrow as once thought

Phase 3: Extended Recovery (2-48 hours)

Muscle repair continues
Protein synthesis elevated for 24-48 hours
Total daily nutrition matters most
Sleep amplifies recovery

Phase 4: Adaptation Complete

Muscle stronger/bigger than before (if nutrition adequate)
Glycogen stores restored
Ready for next training stimulus

What Happens Without Proper Nutrition:

Recovery incomplete before next session
Adaptations diminished or reversed
Cumulative fatigue → overtraining
Injury risk increases
Performance plateaus or declines

🧠 The Science

Evidence-Based Sport Nutrition Principles

Energy Availability

The Critical Concept: Energy availability (EA) = (Energy intake - Exercise energy expenditure) / Fat-free mass

EA Level	Status	Effects
>45 kcal/kg FFM	Optimal	Full recovery, adaptation
30-45 kcal/kg FFM	Reduced	May compromise some functions
<30 kcal/kg FFM	LOW EA	Health and performance impaired

Low EA Consequences:

Hormonal dysfunction (thyroid, sex hormones)
Bone stress injuries
Immune suppression
Menstrual dysfunction (females)
Decreased performance paradoxically
Part of Relative Energy Deficiency in Sport (RED-S)

Protein Requirements

General Population: 0.8 g/kg/day Active Adults: 1.2-1.6 g/kg/day Strength Athletes: 1.6-2.2 g/kg/day Endurance Athletes: 1.2-1.6 g/kg/day (higher if restricting calories)

Protein Timing Research:

20-40g protein per meal maximizes muscle protein synthesis per meal
Distribution across 4-5 meals may be superior to fewer larger doses
Post-workout protein effective, but total daily intake matters more
Pre-sleep protein (casein) may enhance overnight recovery

Carbohydrate Periodization

Training Volume → Carbohydrate Need:

Training Type	Daily Carbohydrate
Low intensity/skill	3-5 g/kg
Moderate (1 hr/day)	5-7 g/kg
Moderate-High (1-3 hr/day)	6-10 g/kg
High (4-5 hr/day)	8-12 g/kg

Periodization Strategies:

Train low: Some sessions with low carb availability (enhances fat oxidation adaptation)
Compete high: Full glycogen for performance events
Not about always low-carb: Strategic use of both states

Hydration Science

Sweat Rates: 0.5-2.5 L/hour depending on individual, intensity, environment

Performance Impact:

2% dehydration: Measurable performance decline
3-4%: Significant impairment, heat stress risk
>5%: Dangerous territory

Electrolyte Needs:

Sodium: Primary electrolyte lost in sweat (varies 200-2000+ mg/L)
Potassium, magnesium: Smaller losses but still important
"Salty sweaters" need more sodium replacement

## 👀 Signs & Signals

Signs of Underfueling

Signal	What It Indicates
Persistent fatigue	Chronic energy deficit
Performance decline	Insufficient recovery resources
Frequent illness	Immune suppression from underfueling
Recurring injuries	Incomplete tissue repair
Mood changes/irritability	Low energy availability affects brain
Loss of menstruation (females)	RED-S, severe underfueling
Low libido	Hormonal suppression
Poor sleep despite tired	Stress hormones elevated
Excessive hunger or loss of appetite	Both can indicate dysregulation

Signs of Overfueling

Signal	What It Indicates
Unintended fat gain	Caloric surplus beyond needs
Feeling sluggish during training	Digestive competition with exercise
GI distress during exercise	Too much food too close to training
Performance decline despite weight gain	Carrying non-functional mass

Signs of Proper Fueling

Consistent energy throughout day
Feeling strong in training sessions
Progressive adaptation (getting fitter)
Stable body composition
Good mood and motivation
Healthy immune function
Normal hormonal function

🎯 Practical Application

Implementing Sport Nutrition

Energy Needs
Macro Distribution
Nutrient Timing
Hydration

Calculating Your Needs

Step 1: Estimate Base Needs

Simple method: Body weight (lbs) × 13-15 for moderately active
More precise: Calculate BMR × activity factor

Step 2: Add Exercise Expenditure

Activity	Approximate kcal/hour
Walking	200-300
Running	600-900
Cycling	400-800
Swimming	500-700
Weight training	300-500
HIIT/CrossFit	600-900

Step 3: Check Against EA

Target: >45 kcal/kg fat-free mass
At minimum: >30 kcal/kg FFM
If cutting weight: No lower than 30 kcal/kg FFM

Practical Example:

70 kg athlete, 15% body fat = 59.5 kg FFM
Minimum EA: 59.5 × 30 = 1,785 kcal AFTER accounting for exercise
If burning 600 kcal in training: Need 2,385 kcal minimum intake

Setting Your Macros

Protein First:

Calculate: 1.6-2.2 g/kg for strength, 1.2-1.6 for endurance
Example: 70 kg strength athlete → 112-154g protein
Spread across 4-5 meals (20-40g each)

Carbs Based on Training:

Low volume day: 3-5 g/kg → 210-350g
Moderate training day: 5-7 g/kg → 350-490g
High training day: 7-10 g/kg → 490-700g

Fat for the Rest:

Don't go below 0.5 g/kg (hormone function)
Typically 1.0-1.5 g/kg works well
Adjust based on calorie needs

Sample Distribution (70 kg, moderate training day, 2,800 kcal):

Macro	Amount	Calories
Protein	140g (2.0 g/kg)	560
Carbs	400g (5.7 g/kg)	1,600
Fat	70g (1.0 g/kg)	630
Total		2,790

Fluid Strategies

Daily Baseline:

~0.5-1 oz per pound bodyweight
More if hot, humid, or high altitude
Monitor urine color (pale yellow = hydrated)

Pre-Exercise:

5-10 mL/kg in the 2-4 hours before
~350-600 mL for most athletes
Include sodium if exercise will be long/hot

During Exercise:

Drink to thirst for most situations
400-800 mL/hour as general range
Weigh before/after to learn your sweat rate

Post-Exercise:

Replace 150% of weight lost
Include sodium for faster retention
Example: Lost 1 kg → drink 1.5 L over next few hours

Electrolyte Needs:

Situation	Sodium Need
<1 hour exercise	Water usually sufficient
1-2 hours, moderate	300-500 mg/hour
>2 hours, hot/heavy sweating	500-1000+ mg/hour
Salty sweater	Individual testing helpful

## 📸 What It Looks Like

Sample Training Day (Moderate Training)

6:30 AM - Wake

Water with electrolytes

7:00 AM - Pre-Workout Breakfast

2 eggs, 2 toast, banana
~400 kcal, 20g protein, 50g carbs

8:00 AM - Training (90 min strength)

Water + electrolytes during
~600 kcal expenditure

9:45 AM - Post-Workout

Protein shake (30g) + apple
~300 kcal, 30g protein, 35g carbs

12:00 PM - Lunch

Chicken breast, rice, vegetables, olive oil
~600 kcal, 45g protein, 60g carbs

3:30 PM - Snack

Greek yogurt with berries and granola
~350 kcal, 25g protein, 40g carbs

7:00 PM - Dinner

Salmon, sweet potato, salad
~700 kcal, 40g protein, 50g carbs

9:30 PM - Pre-Bed

Casein protein or cottage cheese
~200 kcal, 25g protein

Day Total: ~2,550 kcal, ~185g protein, ~235g carbs

Sample Rest Day (Lower Carb)

Same general structure, but:

Reduce carb portions by ~30-40%
Maintain protein intake
Slightly lower total calories
Still eating adequately—just matching lower expenditure

## 🚀 Getting Started

4-Week Sport Nutrition Implementation

Week 1: Assessment

Track current intake (3-day log)
Calculate estimated energy needs
Note current training schedule
Identify obvious gaps (protein? carbs? total calories?)

Week 2: Energy Foundation

Ensure hitting minimum energy availability
Add food if clearly underfueling
Track energy levels and training quality
Don't change everything at once

Week 3: Protein Distribution

Calculate protein target
Spread across 4-5 eating occasions
Add post-workout protein if missing
Note recovery quality

Week 4: Timing Refinement

Dial in pre-workout meal timing
Experiment with during-workout fueling (if long sessions)
Add pre-sleep protein
Compare training quality to week 1

Ongoing:

Adjust carbs based on training volume (periodize)
Monitor body composition, performance, energy
Fine-tune individual preferences
Consider working with sports dietitian for optimization

## 🔧 Troubleshooting

Common Athlete Nutrition Problems

Problem: "I feel too full to train after eating"

Eat earlier (3-4 hours before, not 1-2)
Choose low-fiber, low-fat pre-workout foods
Reduce meal size, supplement with liquid calories
Experiment with timing and food choices

Problem: "I'm gaining fat despite training hard"

Overestimating expenditure or underestimating intake
Track accurately for one week to identify gap
May be eating "around" training but too much total
Quality matters—same calories from better sources often helps

Problem: "I'm always hungry"

May actually need to eat more (underfueling)
Protein and fiber increase satiety
Eating too fast → hunger signals delayed
Sometimes hunger is cumulative from chronic deficit

Problem: "GI distress during training"

Too much food too close to exercise
High fiber/fat before training
New foods without testing
Consider FODMAP sensitivity if persistent

Problem: "My energy crashes in the afternoon"

Blood sugar management—add protein/fat to meals
Underfueling morning/lunch, catching up later
Dehydration accumulation
May need afternoon snack

Problem: "I can't eat enough carbs"

Start with easily digestible sources (rice, bread, fruit)
Liquid carbs (juice, sports drinks) if needed
Spread across more eating occasions
Some athletes simply need higher density foods

Problem: "I train in the morning and can't eat before"

Quick carbs 30 min before (banana, toast)
Train partially fasted if tolerated (shorter sessions)
Larger pre-bed meal night before
Post-workout nutrition becomes more important

## 🤖 For Mo

AI Coach Guidance for Athletes

Assessment Questions:

"What type of training do you do and how many hours per week?"
"What are your goals? (Performance, body composition, general fitness)"
"Walk me through a typical training day of eating"
"How's your energy during and between training sessions?"
"Any GI issues with eating around training?"

Calculation Framework:

1. Estimate daily expenditure:
   - Base: ~13-15 kcal/lb body weight
   - Add: Exercise kcal (rough estimates by activity)

2. Set protein:
   - Strength: 1.6-2.2 g/kg
   - Endurance: 1.2-1.6 g/kg
   - Mixed: 1.4-1.8 g/kg

3. Set carbs by training:
   - Rest day: 3-4 g/kg
   - Light training: 4-5 g/kg
   - Moderate: 5-7 g/kg
   - Heavy: 7-10 g/kg

4. Fat for remainder (minimum 0.5 g/kg)

Common Coaching Scenarios:

Underfueling athlete: "I eat clean but I'm always tired"
- Likely energy availability issue
- Calculate actual needs vs. intake
- "Clean" eating can be calorically insufficient
- Add food, monitor response
Body composition focus: "I want to lose fat but maintain performance"
- Moderate deficit only (no more than 300-500 kcal)
- Keep protein high
- Maintain carbs around training
- Slower rate of loss = better performance retention
New to sport nutrition: "I just eat when I'm hungry"
- Start with protein and timing basics
- Don't overcomplicate initially
- Build habits before optimization
- Track for awareness, not obsession

Red Flags:

Signs of RED-S (menstrual issues, frequent injury, persistent fatigue)
Disordered eating patterns
Extreme restriction combined with high training
GI issues that don't resolve with adjustments

Integration with Other Pillars:

Sleep: Recovery happens during sleep; nutrition supports it
Stress: High training + life stress = higher nutrition needs
Movement: Nutrition enables movement quality and adaptation

## ❓ Common Questions

Q: Do I really need to eat that many carbs? A: If you're training hard, yes. Carbs are your primary fuel for high-intensity work. Under-carbing leads to fatigue, poor performance, and incomplete recovery. Start with recommended amounts and adjust based on results.

Q: Should I use protein supplements? A: Convenient but not necessary. Whole food protein works equally well. Supplements useful for: post-workout convenience, hitting protein targets easily, travel. Not magical—just protein in powder form.

Q: What about fasted training? A: Can work for low-intensity or short sessions. Not ideal for high-intensity or long sessions. Some adaptations from occasional fasted training. Don't make it the norm if performance matters.

Q: Is creatine worth it? A: For strength/power athletes, yes—most studied and effective supplement. 3-5g daily. No loading necessary. Safe, cheap, and works.

Q: How do I know if I'm eating enough? A: Energy levels stable, performance progressing, body composition on track, mood good, immune function normal, hormones healthy. If something's off, often nutrition is involved.

Q: Does meal timing really matter? A: Total daily intake matters most. Timing matters for optimization—especially protein distribution and carbs around training. Don't stress minutes, but general patterns help.

## ✅ Quick Reference

Athlete Nutrition Quick Guide

Macro	Endurance	Strength	Mixed/CrossFit
Protein	1.2-1.6 g/kg	1.6-2.2 g/kg	1.4-2.0 g/kg
Carbs (mod day)	5-7 g/kg	4-6 g/kg	5-7 g/kg
Carbs (high day)	7-10 g/kg	5-7 g/kg	6-8 g/kg
Fat	1.0-1.5 g/kg	0.8-1.2 g/kg	1.0-1.5 g/kg

Timing Cheat Sheet

When	What
3-4 hrs before	Full balanced meal
30-60 min before	Quick carbs if needed
During (>60 min)	30-60g carbs/hour
After (0-2 hrs)	20-40g protein + carbs
Before bed	30-40g slow protein

Key Numbers

Minimum EA: 30 kcal/kg FFM (ideally >45)
Protein per meal: 20-40g for max MPS
Carbs during exercise: 30-60g/hour
Hydration check: Pale yellow urine

💡 Key Takeaways

Essential Insights

Energy availability is foundational—underfueling undermines everything else
Protein requirements are higher than general population (1.2-2.2 g/kg depending on sport)
Carbs fuel performance—don't fear them if you're training hard
Timing matters, but total daily intake matters more
Periodize nutrition with training—more carbs on hard days, less on rest days
Individual variation is real—use guidelines as starting points, then adjust
Consistency beats perfection—sustainable patterns outperform perfect but unsustainable approaches

## 📚 Sources

Position Stands

International Society of Sports Nutrition - Multiple Position Stands
American College of Sports Medicine - Nutrition and Athletic Performance (2016)
Thomas et al. - "Position of the Academy: Nutrition and Athletic Performance" (2016)

Research

Morton et al. - "A Systematic Review of Protein Requirements" British Journal of Sports Medicine (2018)
Burke et al. - "Carbohydrates for Training and Competition" Journal of Sports Sciences (2011)
Mountjoy et al. - "IOC Consensus Statement on RED-S" (2018)

Expert Sources

Dr. Asker Jeukendrup - Sports Nutrition Research
Precision Nutrition - Applied Sports Nutrition

🔗 Connections to Other Topics

Exercise Nutrition Timing - Pre/post workout details
Protein - Deep dive on protein
Carbohydrates - Carb fundamentals
Hydration - Fluid needs

📖 The Story​

🚶 The Journey​

🧠 The Science​

Energy Availability​

Protein Requirements​

Carbohydrate Periodization​

Hydration Science​

Signs of Underfueling​

Signs of Overfueling​

Signs of Proper Fueling​

🎯 Practical Application​

Calculating Your Needs​

Setting Your Macros​

When to Eat What​

Fluid Strategies​

Sample Training Day (Moderate Training)​

Sample Rest Day (Lower Carb)​

4-Week Sport Nutrition Implementation​

Common Athlete Nutrition Problems​

AI Coach Guidance for Athletes​

Athlete Nutrition Quick Guide​

Timing Cheat Sheet​

Key Numbers​

💡 Key Takeaways​

Position Stands​

Research​

Expert Sources​

🔗 Connections to Other Topics​