Fasted FASTED

Fasted Workout Calculator

Find the optimal time to exercise during your fast. Get personalised timing based on your fasting schedule, workout type, and goal.

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The timing of your workout during intermittent fasting can dramatically affect your results. Exercise during the wrong phase of your fast can leave you drained and compromise recovery, while training at the right time amplifies fat burning and preserves muscle mass.

This calculator matches your specific workout type and goal to your fasting schedule, giving you a clear window for optimal training. Whether you want maximum fat loss from fasted cardio or need to preserve muscle during strength training, the timing recommendation adapts to your needs.

Frequently Asked Questions

Should you work out while fasting?
It depends on your goal and workout type. Fasted cardio and light exercise are generally safe and can enhance fat burning. However, heavy strength training while deep into a fast (18+ hours) may compromise performance and muscle preservation. The key is matching your workout timing to your fasting phase.
Is fasted cardio better for fat loss?
Research is mixed but promising. Fasted cardio may increase fat oxidation during the session, particularly at moderate intensity. However, total daily calorie balance matters more for long-term fat loss. Fasted cardio works best when done 12-16 hours into a fast, when your body is actively using fat for fuel.
Can you build muscle while intermittent fasting?
Yes, but timing matters. Schedule your strength training close to your eating window so you can consume protein within a reasonable timeframe after training. Aim for at least 25-40g of protein in your post-workout meal. Many athletes fast, train near the end of their fast, and break their fast immediately after.
What should you eat before and after a fasted workout?
Before: nothing if truly fasted, though black coffee is acceptable and may enhance performance. After: prioritise protein (25-40g) and carbohydrates to replenish glycogen. If your goal is fat loss, you can delay your post-workout meal slightly. For muscle gain, eat within 30-60 minutes of finishing.
Is it dangerous to exercise while fasting?
For most healthy adults, moderate exercise during a fast is safe. However, avoid high-intensity training beyond 18 hours fasted, stay hydrated, and listen to your body. Stop immediately if you feel dizzy, nauseous, or lightheaded. People with medical conditions should consult their doctor first.

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Calculate when autophagy starts during your fast based on meal type, activity level, and age. See your personalised fasting phases and countdown to cellular cleanup.

Fasted tracks your fasting phases so you always know your optimal workout window

See exactly which metabolic phase you are in at any moment. The Fasted app shows you when to train for maximum fat burning, muscle preservation, or performance.

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