Is there an optimum eating window?

[xactly]

Peter Attia's email this morning referenced a study comparing time-restricted feeding windows. This study showed shifting a group of subjects to an early 18/6 TRF schedule (8 a.m. to 2 p.m.) had a number of benefits:

• Avoiding food for several hours (in this case, more than 8 hours) before bed may help lower nighttime cortisol and overnight glucose (and possibly improve sleep quality).
• The eTRF group showed lower glucose, glucose excursion, and insulin levels. They also showed an increased expression in the autophagy gene LC3A, suggesting that more autophagy occurred during eTRF,
• The SIRT1 gene was also upregulated in the morning during eTRF

I've been following a 16/8 TRF schedule, cutting off food around 5 p.m. (bedtime is 9 p.m.). However, I suspect I have high cortisol levels at night because my Oura ring frequently tells me my nighttime heart rate lowers late during the sleep cycle. I also wake up briefly once or twice at night, which I would prefer not to do.

I have followed all the other advice to get my heart rate to lower early during sleep, such as not working out late in the day and practicing good sleep hygiene. I may try adopting an 8 a.m. to 2 p.m. schedule to see if it makes a difference.

[TheresaB]

I've heard a number of sources say it's best to have the biggest meal first then taper off. One reason is that early in the day is when we're most insulin sensitive. That's what I would do if it were practical, but my husband and I enjoy eating our "big" meal together, so we just try to eat no later than 6 pm to allow for digestion before bed time followed by a 16 hour overnight fast. The timing isn't optimal, but we do what we can. Dr Gundry recommends that for those who, due to work, family, etc. obligations can't have their big meal first, to just skip the evening meal once a week to give the glymphatic system a chance to regularly "clean the brain."

[BGTex]

Peter Attia's email this morning referenced a study comparing time-restricted feeding windows. This study showed shifting a group of subjects to an early 18/6 TRF schedule (8 a.m. to 2 p.m.) had a number of benefits:

• Avoiding food for several hours (in this case, more than 8 hours) before bed may help lower nighttime cortisol and overnight glucose (and possibly improve sleep quality).
• The eTRF group showed lower glucose, glucose excursion, and insulin levels. They also showed an increased expression in the autophagy gene LC3A, suggesting that more autophagy occurred during eTRF,
• The SIRT1 gene was also upregulated in the morning during eTRF

I've been following a 16/8 TRF schedule, cutting off food around 5 p.m. (bedtime is 9 p.m.). However, I suspect I have high cortisol levels at night because my Oura ring frequently tells me my nighttime heart rate lowers late during the sleep cycle. I also wake up briefly once or twice at night, which I would prefer not to do.

I have followed all the other advice to get my heart rate to lower early during sleep, such as not working out late in the day and practicing good sleep hygiene. I may try adopting an 8 a.m. to 2 p.m. schedule to see if it makes a difference.

I can’t remember which guru has been saying this for a while now, but Attia’s email didn’t surprise me. Someone, can’t recall who at the moment, has been strongly urging an 8-9 a.m. to 3 p.m. eating window for a while, for all the reasons that Attia’s email covered.

[slacker]

However, I suspect I have high cortisol levels at night because my Oura ring frequently tells me my nighttime heart rate lowers late during the sleep cycle. I also wake up briefly once or twice at night, which I would prefer not to do.

I tend to associate elevated cortisol with elevated HR. Why do you think that high cortisol is lowering your heart rate - or am I misunderstanding your thought process? Either way, adjusting your eating window earlier in the day makes sense.

[xactly]

I tend to associate elevated cortisol with elevated HR. Why do you think that high cortisol is lowering your heart rate - or am I misunderstanding your thought process?

I agree that elevated cortisol is associated with elevated HR.

My heart rate drops at night to around 48 to 52 bpm; however, that drop tends to occur very late in the sleep cycle, usually within an hour or two of waking up. The feedback I get from Oura says because of the late lowering of heart rate, I'm not as rested or recovered from the previous day's activities or stress as I could be. Oura says my heart rate should lower early in the sleep cycle, not late.

The advice Oura provides says to avoid eating or exercising late in the day, which I do. Because my heart rate is lowering late in the cycle, and I have sleep continuity issues, I suspect high cortisol is the culprit.

Attia says getting adequate, high quality sleep is about managing three cycles: adenosine, melatonin and cortisol. I think I'm doing well with adenosine and melatonin, but not with cortisol. That's why this article caught my interest. I'm hoping an eTRF schedule will allow my cortisol cycle to reset to higher in the morning and lower at night.