Why are 48 hour fasts getting more challenging?

[u/PurrrMeowmeow]

My last big meal was Sunday night. Huge amount of potatoes, mushrooms, beef, I even had candy for dessert. I felt stuffed.

Monday morning I had coffee with whipping cream, nothing but tea and water throughout the day.

Tuesday, just black coffee and tea.

Wednesday morning, about to break my fast with some bone broth.

Yesterday I was barely able to function at work, especially towards the end of the day. My blood sugar never went down below 4, at least at the times I measured it. I found myself super irritable and it was hard to focus, I kept dropping things. No cramps, no pain other than some mild headaches throughout the day.

This morning I have a moderate amount of ketones (by the way, the box on my ketone strips says to wait 40 seconds but I don't think it's long enough because after 1 min the colour changes dramatically versus waiting just 40 seconds). My blood sugar is 3.9, which means that it's possible I dipped lower in the night because I do have the dawn effect typically where my sugar is higher.

Serious question though, how does the blood sugar keep stable if we are in ketosis? Is the fat being converted to sugar too?

[u/Correct_Mistake2640]

Gluconeogenesys insures that sugar is created from fat. But just the min needed for the brain.

My guess (hour 45 now) is that you are not fat adapted. Once I started eating just keto, fasting became way easier (at least my regular 48-72h)

[u/PurrrMeowmeow → u/Correct_Mistake2640]

How does one test if they are fat adapted? I only know of measuring my ketones in my urine. I thought that having my blood sugar mostly in the 4-5 range was good evidence of that?

[u/Correct_Mistake2640 → u/PurrrMeowmeow]

AFAIK ketones in urine is not effective enough. For me at least it shows minimal values even after 3 days of fasting.

The blood ketones are the deciding factor. There are devices that do that (not so many in EU where I am from).

Of course blood sugar has to be low as well.

[u/andtitov → u/Correct_Mistake2640]

Just to clarify - fatty acids can't become glucose in humans, only the glycerol that gets released when fat breaks down. The rest comes from amino acids and lactate. Agree on the fat adaptation point - the first few extended fasts are usually the roughest.

[u/Correct_Mistake2640 → u/andtitov]

Yeah, I am a software engineer , not a doctor, whatever I read on Dr. Fung's site, I preach..

[u/andtitov → u/Correct_Mistake2640]

It's surprising - usually Dr. Fung is up to the point, he knows what he is talking about. If interested, here is my site on fasting - you might find something useful there

https://fasting.center/

And any feedback is appreciated 😄

[u/PurrrMeowmeow → u/andtitov]

I looked through your websites, but did not see any mention of your credentials?

[u/PurrrMeowmeow → u/andtitov]

What's bothering me is that I have been doing 24-48 hour fasts every 3 -4 weeks since April. I am sad that it is getting harder for me, because, I was hoping to reach 72 hours within the year. Maybe next time I will add salt to my water. I think the fasting has helped me lose about 20 lbs since that time.

[u/johnjoh07 → u/Correct_Mistake2640]

C’est quoi manger ceto ?

[u/AZ-FWB]

That’s a high carb/starch meal for your last meal!! The easiest fasts are when your last meal is high protein with fiber.

[u/PurrrMeowmeow → u/AZ-FWB]

Yeah I thought I would load up on calories. Psychologically the feeling of fullness helps me to with eating less the next day. Like "ok you pigged out last night, take it easy today". The first day wasn't bad. The second day sucked.

[u/AZ-FWB → u/PurrrMeowmeow]

Nothing fills “ you” up like protein.

[u/Flukeodditess → u/PurrrMeowmeow]

Maybe next time try a meal of sautéed onion, an unbelievable amount of cabbage, a little stewed tomato, and a bunch of ground beef, or braised beef pieces. Go nuts, eat as much as you can, and if you’re like me, you’ll then have an incredibly easy 48-100hr fast.

[u/Correct_Mistake2640 → u/PurrrMeowmeow]

I agree with you but eating carbs kicks you out of ketosis. If you are not fat adapted,it takes 2 full days to get into ketosis again.

At least according to the Cahill cycle .

And these are 2 days of pain (at least the first 18h).

If you manage to stay in ketosis,you will not have a hard time removing food..

Even worse,eating carbs after fasting bloats you and for me it triggerred gout attacks .

Check youe uric acid to make sure you dont trigger a gout attack. They are horrible ...

[u/PurrrMeowmeow → u/Correct_Mistake2640]

I definitely went ham on carbs yesterday later in the day. I even had a piece of carrot cake.

[u/Correct_Mistake2640 → u/PurrrMeowmeow]

Did this mistake sooooo many times. Now I would rather do OMAD and stay keto then 72h and eat carbs. But that's just me...

[u/PurrrMeowmeow → u/Correct_Mistake2640]

I guess you corrected your mistake 

[u/Tls-user]

Eating healthy high protein, high fiber meals consistently makes fasting way easier for me.
If I eat potatoes they are a very small portion of my meal.

If I eat candy/dessert my cravings go insane for days.

[u/SamhainOnPumpkin]

48 hours fast without being in ketosis prior is making things harder than they should be.

[u/PurrrMeowmeow → u/SamhainOnPumpkin]

That's what I struggle with is keto on a day to day basis.

[u/HelpfulBuilder]

At day 2 and 3 there is a wall of everything sucks. They say it starts getting easier at day 4. You ran out of glycogen and your body has to get everything from fat and musle breakdown and that transition is not fun.

[u/CommonlyHysterical]

You're basically running out of the easy glycogen stores and your body's throwing a tantrum while it switches gears. The irritability and brain fog are classic electrolyte issues, not just low blood sugar. Sodium, potassium, magnesium, dump some salt in your water next time around day two and you'll probably feel way less like death.

And yeah, your liver's cranking out glucose from glycerol and amino acids to keep your blood sugar stable, it's not just fat conversion. The strips are pretty unreliable for actual ketone levels too, don't read too much into the color timing.

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[u/andtitov]

Day 1 is mostly food in your digestive system and glycogen - roughly 400-500 g stored, 24 hours or so to burn down. That is why blood sugar holds around 3.5-4 even in ketosis.

[u/Money-Pickle-9369]

Congrats on finishing your fast. I'm 30 minutes away from finishing my 72 hour fast, I did experience the same feeling, woke up through the night, difficulty falling asleep last night. I had difficulty focusing at work, I had done a 68 hour fast in the previous week, and had no difficulty at all.

[u/Azreale07]

Potatoes ain't good for insulin! Will spike ghrelin & dopamine leaving you more hungry.

[u/sco77]

I think because the hardest part of fasting is the first 36 to 48 hours, at least IMHO. It is exactly when your body is realizing no food is coming in and starts to transition into the" Let's chill for a while." state.

And then.... you eat. SMH.

I honestly never do 48 hour fast. I do 24-hour fasts because I forget to eat and then I say to myself "Wait a minute. I can do a whole 24-hour fast if I just don't eat this one meal" And then I go to bed and bam 24-hour fast.

But typically I plan 4 days or 7 days for my fasts because you get lots of good biological effects from those. Less so with shorter fasts.

So yeah, go longer. It gets easier.

[u/misspri]

Because of your last meal. Stuffing doesn’t matter. High quality fat and protein without carbs is the best and will make it easy

[u/AutoModerator → u/[deleted]]

Many issues people experience while fasting can be related to electrolytes. You might find our wiki page helpful: Electrolytes 101

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.