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Comment by inglor_cz | Hacker News Reader

N == 1 here.

I had a huge drop in blood pressure once I started fasting daily. Even though I lost only a modest amount of weight (approx. 10 pounds; I was never obese, only slightly overweight with BMI cca 27), my blood pressure plummetted from 150/95 with medication to some 115/75 without medication within a month.

This holds even when I no longer fast daily, only a few times a week. Additional Concor, taken against post-Covid arrhythmias, reduced my BP to some 105/70 when relaxed. Going any lower would actually mean a risk of fainting.

This seems to be consistent with the theory of gut microbiota being reshaped. I can also tolerate milk slightly better than before; my tolerance still has limits, but I won't get a rash after a single cappuccino, which I most definitely used to before.

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Last year I fasted for a week just to see if I could do it, I really wish I had before/after stats and bloodwork done. I don't think it's something I will do again.

A week! That is a significant fast. My max was 70 hours or so; I do not plan to do that again, either.

Well I would say that it gets easier as you go, other than you feeling progressively weaker and weaker. You probably made it through the worst of the hunger and cravings at 70 hours

At the 70 hour mark, I wasn't exactly hungry, but a bit irritable, cold and distracted. And yes, a little weaker. Pulling off any demanding work in that condition would be nigh impossible for me.

Wow I start to pass out at around 2pm and I get a terrible migraine past that if I haven’t had breakfast. But I’m only 130lbs and 5’11” so I don’t have much storage and usually have hypotension. I wonder what would happen if I push it

It depends on your internal (fat) reserves. I'm 58kg 1m83 (BMI 17.32), so I wouldn't really try such a long period. But there are days I eat a lot, I build some glycogen reserves (easily available fat, made from glucose) due to my diet with much fruits, or other stuff like rice, honey, then the next days I can fast intermittently and use that glycogen. As a result I can't really gain weight, it always balance itself to that weight.

I think people with more weight, have deeper fat, and it'll take longer to use it. I remember seeing an article that our ancestors possibly were hibernating. The more fat, the more time you can spend fasting, even on a dry fasting (fat holds water), but in that case it's important to limit physical exercise

Glycogen is a polysaccharide, not fat. It is metabolized in a completely different way.

Do you mind sharing your daily fasting routine. I only tried intermittently and always wanted to give it a more serious try and I have to start somewhere.

My sweet spot seems to be 18/6.

I prefer to go without breakfast and have a lunch and a dinner 6 hours apart, because I hate to sleep with an empty stomach. I drink unsweetened coffee and tea (0 calories and may act as appetite suppressant). I generally limit sugar in my food, though not to zero.

On my non-fasting days, I have a breakfast, but I try to have no more than 3 meals a day. No snacking.

I decide whether to fast or not by the state of my hunger in the morning. If I am ravenous, I have a breakfast and a non-fasting day. If I feel only slightly empty, I go without breakfast to a total length of 17-19 hours of fasting.

I am now experimenting with continuous glucose meter to find out what meals send my glucose too high. This, again, seems to be individual. Rice and potatoes seem to act really crazy. Interestingly, pizza not so much.

18/6 has never done anything to my BP, I've been doing it for 10 years.

I suspect the biggest impact was trying to lose weight and changing your diet. In my case changing my diet has noticeable and immediate effect to any physiological metric than any other "trick".

I didn't change composition of my diet much back then, but I noticed that on days when I fast longer, my BP goes even lower. I could probably fast myself into lightheadedness now on Concor (not that I want to).

People are fairly diverse, so different reactions are to be expected. Our gut microbiota is diverse, too.

I also noticed that even slight amounts of alcohol (1 glass of wine) are visible on my BP for about 24 hours after. An increase of 5-7 points.

What CGM are you using?

Abbott FreeStyle Libre first generation, which is the only one available in my country. I know that there are newer generations of the sensor, but I do not want to go through the hassle and extra expense of importing them from the UK or so.

What was your fasting routine? and for how long did you do it? Just interested in seeing what others are doing. I know there's 16-8 (16 hours no-eating, 8 hours where you can eat).

See my other reply here:

https://news.ycombinator.com/item?id=27868099

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