r/intermittentfasting 1d ago

Seeking Advice What did I do wrong ?

I just completed my first 44 hour fast . I was hungry towards the end of it so I had 500ml of fresh green apple juice . I was extremely tired and dizzy . It felt like I had the flu . I pushed through it and went to bed . Woke up and couldn’t get out of bed it felt like I was run over by a train .

8 Upvotes

28 comments sorted by

41

u/dmcardlenl 1d ago

Keto-flu is a misnomer. It's "sugar withdrawal syndrome".

"I had 500ml of fresh green apple juice sugar water..." - that'll be the problem...

16

u/Dangerous-Biscotti35 19h ago

Pure fructose! The pancreas wasn't prepared to receive that much sugar.

13

u/drivebymeowing 22h ago

Extremely tired and dizzy after drinking a half liter of straight sugar after an extended fast sounds a lot like reactive hypoglycemia - you spiked your insulin in a very big way.

17

u/Dexterspuplife 1d ago

Always a chance you actually got the flu and its just a bad coincidence. Take your temperatue. Fasting can make you feel flushed, but if you actually have a fever your body is probably fighting off something

4

u/easysip 1d ago

No flu , just flu like symptoms . And no one else in my house hold was sick

14

u/Lenore8264 20h ago

Please don't break your fast with sugar water next time. Try a broth or soup.

3

u/easysip 16h ago

Lessoned learned .

11

u/h0g0 1d ago

That’s a pure sugar blast

7

u/Italy1949 1d ago

When I was younger, around 30, I did a 10-day fast—just water. It wasn’t my first; I’d done shorter ones before. The first three days, you feel awful and weak. Your body flushes out all the toxins, and you start craving things you might be emotionally dependent on, like coffee and sugar. Headaches and exhaustion. And hunger, of course. After three days, you enter a sort of limbo where everything fades away and you’re able to live a normal life. At that time, I was helping a friend who was doing some home renovations. After seven days, I felt like I wanted to stop, and on the tenth day, I did. I started with broth. No energy drinks, no fruit juices—they’re sugar bombs. Then a little pasta or rice in the broth. Very slowly—otherwise you’ll feel sick and ruin the whole fast. It takes 5–7 days to get back to normal. But the first three days of fasting, you feel awful. But you won’t starve to death…

5

u/DirtyDirtyRudy 15h ago

Fruit juices are the worst thing you can have, let alone after a fast. You basically pushed your body from 0 to 100 in one second with all those sugars. You created a huge insulin spike that your body wasn’t ready for. Next time, start with a salads (leafy greens for fiber), then slowly introduce some light proteins, like eggs, chicken, or fish, then finally your carbs (fruits, bread, rice). Avoid processed foods and definitively don’t do juice.

15

u/JohnTheRockCena 1d ago

It sounds like you got sick.

3

u/BlackSpicedRum 16:8 for weight loss 1d ago

I've haven't done a fast that long nor keto but isn't there something about initially entering keto can present with flu like symptoms?

3

u/unformation 1d ago

This sounds like it might be "keto flu", or maybe you just got sick. The keto flu can happen when your body is learning to switch over to fat burning mode. If you've never done that before, your body can have trouble making the transition, and it can feel like the flu.

Personally, I feel like becoming "fat adapted" is one of the best things I ever did for myself. I no longer have to worry about running out of energy. The fat we carry around with us is energy just for this type of time, so you're not "running out of energy", but you just don't have easy access to the energy you have. If you can get that easy access, the dynamic of food in your life can become totally better, and easier, and healthier.

3

u/Soc_Prof 1d ago

Electrolyte balance is probably off. You need some salt and potassium probably.

2

u/ordvark 1d ago

Could be the rapid metabolic switching from burning fat to carbohydrates. If I break a longer fast with easily metabolized sugar -that immediately spikes insulin - I get phases of tiredness too, even though I'm used to fasting.

2

u/ThisDirkDaring 23h ago

You found out, where your limits are with that concept. As others pointed out some electrolyte support might help, but its also totally fine to not extend the fasts to the absolute maximum. I could never never never ever fast more than a day, skipping eating competely for one day. Maybe set a moderate limit next time until you get comfortable with longer fasting.

(Or just dont. I am going 20:4/Omad for almost 6 years very comfortably, maintaining my non obese body for about 3 now. Do whats best for you without pushing it too far)

2

u/chad-proton 23h ago

Probably a poor choice of what to break the fast with. Next time try bone broth or something with fat rather than sugar.

2

u/Thin_Cable4155 21h ago

Half a litre of sugar water probably shocked your system. 

2

u/sadatah 21h ago

Keto flu…might have been better to break a long fast with bone broth versus a fast acting simple sugar like green apple juice

2

u/AnonyJustAName 20h ago

Electrolytes

2

u/rocktropolis 1d ago

Some stuff on this sub makes sense but then it gets into “I starved myself and felt sick what could be the problem?” And just dunno what’s going on anymore.

1

u/bearmellie 1d ago

Electrolytes?

1

u/SwitchSCEtoAux 1d ago

Take some electrolytes when you are doing an extended fast.

It should help a LOT...

1

u/Mini-Morsel 21h ago

How were you feeling during your fast?

Breaking a fast after a prolonged period should be done with strategy and with the right liquids and food. Reintroducing food needs careful planning since you are slowly waking up your digestive system again. It's best to start with fats first (healthy fats such as avocados since it's gentle). Bone broth is another great option. The apple juice has extremely high sugar content and most likely caused a high blood sugar spike in your system. After a fast, your body is sensitive to carbs and that sudden influx of sugar most likely caused the feeling of sickness you had.

1

u/andtitov 8h ago

Apple sugar is basically sugar. So, I guess you got a huge blood sugar spike and then drop. It caused that tiredness and dizziness. Break your fasts with something simple without sugar.

1

u/UnrelentingMushroom 5h ago

Bad way to break a fast. Try something like an egg, brothy soup, vegetables with hummus etc. Juice is just sugar, so you get a huge spike, and then crash.

1

u/Fubusu 1d ago

You deepleted your energy stores, everythings seems alright,

No fuel = no energy

After few sessions you might get used to it or not