What actually destroys muscle is poor hydration, insufficient protein, and improper training.
If you want to finish your fasting period maintaining muscle mass or even losing fat without sacrificing muscle, focus on three main things: hydration, protein, and managing training intensity.
Hydration for Athletes During Fasting
Muscles are mostly water.
When fluids drop, performance decreases, fatigue rises, and blood flow to muscles weakens.
Even a 2% drop in body weight from dehydration can significantly reduce strength and endurance.
Training After Your Eating Window
Never train without drinking water:
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1 hour before training: 400–600 ml
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During training: sip every 10–15 minutes (150–250 ml depending on sweat)
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After training: 400–600 ml
Goal: maintain blood volume, regulate temperature, and reduce joint stress.
Training Before Breaking Your Fast
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Lower intensity
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Train close to the end of the fasting period
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Immediately after your fasting window, rehydrate
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If the workout is very heavy, it’s better to train after breaking your fast
Note on Fat Burning During Fasted Training
Training before breaking your fast can help your body use fat as fuel.
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Keep intensity moderate or light
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30–45 minutes is enough
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Immediately rehydrate and consume protein to protect muscle from breakdown (muscle catabolism)
How to Distribute Water Throughout the Day
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At the start of your eating window: 2 cups (250 ml each = 500 ml)
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Every 30–45 minutes: 1 cup, according to thirst
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Before training: 2 cups
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After training: 2 cups
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Before fasting (final meal/drink): 2–3 cups
Daily average intake:
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Moderate athletes: 3–4 liters, depending on training intensity and sweat
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Heavy lifters or high-intensity athletes: 5–6 liters
Increase Protein to Reduce Muscle Breakdown
Want to burn fat? Great.
But don’t let your body eat your muscle (muscle catabolism).
During fasting, calories are often lower, and the body may use muscle tissue as energy if protein intake is insufficient.
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Take your daily protein requirement and distribute it between meals
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Choose clear sources: meat, chicken, fish, eggs, dairy, legumes
Fast vs. Slow Protein
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After eating or post-workout: fast-digesting protein → eggs, chicken, fish, whey protein
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Before fasting: slow-digesting protein → cheese, yogurt, casein
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Slow protein protects muscles during long fasting hours, while fast protein rebuilds muscles quickly after feeding
For plant-based athletes: legumes, lentils, chickpeas, and quinoa are excellent protein sources and can be added to meals to meet daily protein needs.
Adequate protein reduces muscle breakdown, preserves strength, and supports recovery—even during a calorie deficit for fat loss.
Lower Training Intensity to Protect Joints and Nervous System
Sleep loss and irregular meal timing put stress on your nervous system.
Lifting maximal weights with the same intensity could overwork your body and increase injury risk.
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Reduce intensity by 15–25%
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Maintain correct form, feel the muscle working, and don’t overdo it
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Fasting periods are a chance to rest your joints and muscles instead of risking injury
How to Burn Fat Without Losing Muscle
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Resistance training 3–4 days per week
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Add light cardio according to your capacity
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Keep protein intake high
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Avoid overindulging in sweets during eating windows
A small calorie deficit with enough protein and resistance training = fat loss while maintaining muscle mass.
Summary
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Drink water consistently during eating windows and while training
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Increase protein to reduce muscle breakdown, with attention to fast and slow protein
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Reduce training intensity slightly to protect joints and the nervous system
Fasting is about smart management, not a muscle challenge.
This article was created in collaboration with Coach Hamza Kafawein, providing content based on precise movement science and exercise physiology principles to deliver practical and reliable advice, free from common fitness myths.
Contact Coach Hamza
For questions or extra guidance, reach out to Coach Hamza Kafawein directly on Instagram: hamza.kafawein
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