Can you do intermittent fasting every day?
Yes, daily 16/8 is safe for most people. But there are nuances depending on the protocol and on who you are.
Part of the complete guide How to start intermittent fasting and pick your protocol
What the science saysIntermittent Fasting Every Day? What's Safe
A daily 16-hour fast (16/8) is sustainable for most healthy adults and is the most studied approach. Fasts of 24 hours aren't a good idea daily: alternate-day fasting trials show results similar to calorie restriction, higher dropout, and, in lean people, less fat loss. Long fasts are best saved for once or twice a week.
- Alternate-day fasting for 1 year: -6.0% body weight versus -5.3% with daily calorie restriction (not significant); 38% dropout (Trepanowski 2017). [1]
- 4 weeks of strict alternate-day fasting cut intake by 37% and reduced trunk fat in healthy adults, with no adverse effects (Stekovic 2019). [2]
- In lean adults, alternate-day 24 h fasting lost less fat, 1.6 lbs (0.74 kg), than the same daily calorie restriction, 3.9 lbs (1.75 kg) (Templeman 2021). [3]
Daily 16/8: yes, it's safe
For most healthy adults, running 16/8 every day is perfectly sustainable. In fact, daily consistency is what turns it into an automatic habit and gets you results.
Long fasts: better NOT daily
Fasts of 20-24 hours or more are a different story. Those aren't a good idea every day: they raise the risk of an excessive deficit, muscle loss, and hormonal disruption. Save the long ones for once or twice a week at most.
When you should NOT fast daily
- Women with hormonal imbalances: 3-5 days a week usually works better.
- Athletes in a bulking phase: they may need a wider eating window on certain days.
- Stretches of high stress or poor sleep: fasting adds stress, so sometimes it pays to ease off.
Listen to the signals
Fasting daily is fine as long as you feel energized, sleep well, and aren't obsessing over food. If chronic fatigue, irritability, or binges show up, cut the frequency. Fasting should add to your life, not run it.
How Ayúname helps
Ayúname lets you switch it up: 16/8 on normal days, wider windows when you need them. Flexibility with consistency, guilt free.
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Frequently asked questions
Is it bad to do intermittent fasting every day?
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Scientific sources (4)
- Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults. JAMA Internal Medicine, 2017.
- Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans. Cell Metabolism, 2019.
- A randomized controlled trial to isolate the effects of fasting and energy restriction on weight loss and metabolic health in lean adults. Science Translational Medicine, 2021.
- Clinical application of intermittent fasting for weight loss: progress and future directions. Nature Reviews Endocrinology, 2022.