Four years ago, I discovered intermittent fasting (IF) and it transformed my fitness journey, especially between intense Ironman training blocks.

During fasting, your body burns fat and optimizes body composition—vital for athletes.

After Ironman Weymouth, returning to fasting made me feel leaner and more focused, with fewer cravings.

In this article, explore how fasting can boost sports performance, improve health, and fit into your training routine.

So, how can you use intermittent fasting to enhance your running?

The Main Feature

Leg One: Decoding the Science of Intermittent Fasting

I’ve been fasting on and off for the better part of four years, aside from the heavy training blocks in preparation for my first Ironman.

Intermittent fasting (IF) is not just a dietary trend; it's a structured approach to eating that alternates between defined periods of fasting and eating. This method, deeply rooted in our evolutionary history, emphasizes the timing of meals rather than specific dietary changes. The most common intermittent fasting methods include:

• 16/8 Method: Involves 16 hours of fasting followed by an 8-hour eating window.

• 5:2 Approach: Normal eating is interspersed with two days of reduced calorie intake per week.

• Eat-Stop-Eat Method: Involves complete fasting for 24 hours, once or twice a week.

Physiological Effects

The physiological effects of intermittent fasting are profound and multifaceted. During fasting periods, the body undergoes several metabolic shifts:

• Insulin Levels: A significant decrease in insulin levels occurs, facilitating the breakdown of body fat for energy. This is particularly important for athletes seeking to optimize body composition.

• Human Growth Hormone (HGH): There's a notable increase in HGH levels, which plays a vital role in muscle growth and repair – crucial for recovery and performance enhancement.

• Norepinephrine: Fasting triggers a rise in norepinephrine, contributing to an increased metabolic rate and enhanced fat burning.

These metabolic changes are accompanied by cellular and molecular adaptations:

• Autophagy: Fasting periods initiate a process known as autophagy, where cells undergo self-cleansing and removal of damaged components. This process is crucial for cellular health and optimal functioning, potentially leading to improved muscle recovery and longevity.

T-1: Mental Preparation

Leg Two: Intermittent Fasting in Sports Performance

The application of fasting in sports is multifaceted. Its primary benefit lies in its ability to optimize body composition, crucial in sports where weight categories or power-to-weight ratios are key. The hormonal environment fostered by fasting promotes fat loss while preserving lean muscle mass, offering a significant advantage in weight-sensitive sports.

However, the integration of fasting with training demands careful consideration. Athletes must strategically align their fasting schedules with their training cycles to ensure they have adequate energy for high-intensity sessions. Fasting might be more appropriate on rest days or during periods of low-intensity training.

For example, during my training for Ironman Weymouth, I did NOT intermittent fast. I had too many training sessions to complete which required a huge number of calories. Since no longer training for Ironman, I’ve switched back to fasting and feel great. I’m leaner, have fewer food cravings, and feel more focused.

Endurance Performance

There's growing evidence suggesting that fasting can enhance endurance performance by improving mitochondrial efficiency and increasing resistance to oxidative stress. These adaptations are beneficial for endurance athletes, potentially leading to improved performance. However, individual responses can vary, and the research is still evolving. I certainly haven’t tried this process during an intense training block.

Leg Three: General Health Benefits, Advanced Considerations, and Practical Implementation

Beyond athletic performance, fasting offers extensive health benefits:

• Glucose Regulation: Improved glucose regulation.

• Inflammation: Reduced inflammation.

• Neuroprotective Effects: Potential neuroprotective effects, all of which are vital for an athlete's long-term health and performance.

Starting Intermittent Fasting

Starting IF should be a gradual process. Athletes might begin with a 12-hour fasting window, slowly extending it to 16 hours or more. It's crucial to consume nutrient-dense foods during eating windows to ensure adequate energy and nutrient intake. Hydration remains essential during fasting periods, with water, herbal teas, and black coffee being suitable options.

Advanced Considerations

Advanced considerations for athletes include the timing of fasting in relation to training schedules. It's essential to align fasting periods with lower-intensity training days or rest days to ensure optimal performance during high-intensity sessions. The timing of nutrient intake around training sessions becomes crucial, especially when training falls within or close to fasting periods. Post-workout nutrition, in particular, should not be neglected, as it plays a critical role in recovery and muscle synthesis.

Psychological Aspect

The psychological aspect of fasting is equally important. Adapting to a new eating pattern requires mental resilience and a positive approach. Athletes should monitor their physical and mental responses closely and adjust their fasting regimen accordingly. It's also vital to ensure that fasting does not lead to disordered eating patterns or negatively impact mental health.

Enhanced Understanding

Additional Benefits of Intermittent Fasting

1. Improved Cognitive Function: Intermittent fasting has been shown to enhance brain function and protect against neurodegenerative diseases. This can lead to better focus and mental clarity during training and competition.

2. Enhanced Immune Function: Fasting may help in modulating the immune system, potentially reducing the risk of illness and improving overall health.

3. Increased Longevity: Studies in animals suggest that intermittent fasting can extend lifespan by promoting healthier cellular function and reducing the risk of chronic diseases.

4. Gut Health: Fasting periods give the digestive system a break, which can improve gut health and reduce symptoms of gastrointestinal distress, which is beneficial for athletes who often face digestive issues during intense training and competitions.

Practical Tips for Athletes

1. Personalized Approach: Tailor your fasting schedule to fit your training and competition calendar. Consider working with a sports nutritionist to optimize your fasting regimen.

2. Nutrient Timing: Pay special attention to meal composition and timing. Ensure that meals are rich in proteins, healthy fats, and complex carbohydrates to sustain energy levels.

3. Monitor Performance: Keep track of your performance metrics, body composition, and overall well-being to determine how fasting is affecting you.

4. Flexibility: Be flexible and willing to adjust your fasting schedule based on your training demands, competition schedule, and how your body responds.

Conclusion

Intermittent fasting offers a unique approach to nutrition and physiology, with potential benefits for body composition, metabolic health, and athletic performance. However, its application should be highly individualized, considering each athlete's specific training schedule, performance goals, and overall health.

If you’re training for an Ironman, Hyrox, or UTMB race, introduce this to your training gradually, if at all, because you’ll be entering fat-adapted training.

So, that’s how intermittent fasting can help you.

Coaches Corner

Workout of the Week: 45-Minute HIIT Gym Session

Total Duration: 45 minutes

Workout Structure:

Warm-Up (5 minutes)

• Dynamic Stretching: Perform dynamic stretches for 2 minutes, including leg swings, arm circles, and torso twists.

• Light Cardio: 3 minutes of light cardio such as jogging in place, jumping jacks, or skipping.

Focus: Prepare your muscles and cardiovascular system for intense effort.

Circuit 1: Full-Body Blast (15 minutes)

Perform each exercise for 45 seconds, followed by 15 seconds of rest. Complete the circuit three times.

1. Burpees: Bodyweight exercise.

2. Dumbbell Thrusters:

   • Men: 15-25 lbs (7-11 kg) dumbbells

   • Women: 8-15 lbs (4-7 kg) dumbbells

3. Mountain Climbers: Bodyweight exercise.

4. Kettlebell Swings:

   • Men: 20-35 lbs (9-16 kg) kettlebell

   • Women: 10-20 lbs (5-9 kg) kettlebell

5. Push-Ups: Perform standard push-ups or modify to knee push-ups as needed.

Focus: Boost heart rate and engage multiple muscle groups.

Circuit 2: Strength and Core (15 minutes)

Perform each exercise for 45 seconds, followed by 15 seconds of rest. Complete the circuit three times.

1. Deadlifts:

   • Men: 40-60 lbs (18-27 kg) dumbbells or barbell

   • Women: 20-40 lbs (9-18 kg) dumbbells or barbell

2. Plank with Shoulder Taps: Bodyweight exercise.

3. Box Jumps: Use a 12-24 inch (30-60 cm) box or platform.

4. Russian Twists:

   • Men: 10-15 lbs (4-7 kg) weight or medicine ball

   • Women: 5-10 lbs (2-4 kg) weight or medicine ball

5. Walking Lunges:

   • Men: 15-25 lbs (7-11 kg) dumbbells

   • Women: 8-15 lbs (4-7 kg) dumbbells

Focus: Build strength and stability while keeping the heart rate elevated.

Circuit 3: Cardio Finisher (10 minutes)

Perform each exercise for 30 seconds, followed by 30 seconds of rest. Complete the circuit twice.

1. Jump Rope: Quick and controlled jumps, focusing on maintaining a steady rhythm.

2. High Knees: Drive your knees up towards your chest, pumping your arms for added intensity.

3. Battle Ropes: Use battle ropes that are comfortable for your strength level (1.5 to 2 inches in diameter, 30-50 feet in length).

4. Jump Squats: Bodyweight exercise.

5. Sprint Intervals: Use a treadmill or the gym floor to sprint as fast as possible for 30 seconds.

Focus: Maximize calorie burn and cardiovascular endurance.

Cool Down (5 minutes)

• Static Stretching: Focus on major muscle groups worked during the session, holding each stretch for at least 30 seconds.

• Deep Breathing: Practice deep breathing exercises to lower your heart rate and relax your body.

Additional Tips:

• Hydration and Nutrition: Ensure you're well-hydrated before starting, and consider a light snack if you're working out on an empty stomach.

• Pacing and Monitoring: Listen to your body and modify exercises as needed to match your fitness level.

• Form and Safety: Focus on proper form to prevent injuries and maximize effectiveness.

This HIIT gym workout is designed to challenge your entire body, boost your metabolic rate, and improve your overall fitness. Incorporate this session into your weekly routine to see significant gains in strength, endurance, and cardiovascular health.