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Short Summary
Main recommendation: Dr. Ziv Ab advises against extreme intermittent fasting and says that eating within a window of about 12 to 13 hours, meaning avoiding late-night eating, is what he generally recommends, while he does not treat omega-3 quality claims as settled without lab data. He argues that health comes mainly from good diet, sleep, physical activity, low stress, and whole-food nutrition rather than supplements.
Key Points
- A recent study linked very long-term, extreme intermittent fasting (eating windows under 8 hours, averaging about 8 years) to higher mortality, but the study does not define the window precisely and the researchers themselves say it is unclear whether fasting causes the outcome or whether other factors, such as pre-existing illness, explain it.
- Dr. Ab says he does not personally follow a 16/8 schedule and has never generally recommended it; he sees no evidence of harm from ending eating 12 to 13 hours before sleep.
- Two common mistakes with fasting: treating the fasting hours as permission to eat any junk food in the eating window, and skipping breakfast and lunch so most calories are eaten late in the evening, which he says is metabolically less effective and harms sleep.
- Extreme or prolonged fasting can lead to muscle loss, which he says is harmful; he recommends strength training, especially for people combining different fasting styles.
- On the omega-3 claims in Israel about excessive oxidation levels, he says he would need lab results, a reliable objective lab, and the statistical sample before commenting on them.
Details Worth Noting
- Concrete instructions:
- If you practice intermittent fasting, end your eating about 12 to 13 hours before sleep rather than shortening the window further.
- Keep your eating window as early in the day as possible; stop eating earlier in the evening so that sleep is not disturbed.
- Do not skip breakfast and lunch and concentrate most calories in the evening.
- Do not treat the fasting period as a reason to eat any food during the eating window.
- If you use fasting, add strength training (resistance exercise) to protect muscle mass, especially if you combine different fasting styles.
- Adjust any dosage or approach to the individual, since he says everything depends on dose and personal fit.
- Do not base your health on supplements; prioritize good nutrition, sleep, regular physical activity, smiling, and stress reduction.
- The study's authors note it is unclear whether the mortality link is caused by shorter eating windows or by other factors, such as existing illness; this question should be considered before worrying about fasting.
- He frames his comments as his own view and does not present them as professional medical advice.
Bottom Line
The cited study shows a correlation between extreme long-term fasting and higher mortality, but the researchers themselves say it's unclear whether fasting causes this or other factors (like pre-existing illness) explain it; his practical takeaway is to keep fasting moderate, eat earlier in the day, and rely mainly on diet, sleep, exercise, and stress management rather than supplements or unverified claims.
