Felt amazing on fast, then extremely tired after breaking it

(Pete Bernardin) #1

Hey gang!

Background: I’ve been doing keto for about a month (paleo before that). I feel as though my body is fairly fat adapted. I IF every day, nearly do OMAD but try not to eat too much protein in one sitting due to insulin spike, maybe eat in a 4 hour window. I have absolutely no trouble whatsoever fasting 20 hours a day. I feel fantastic while fasting, tons of energy. I’m a plumber and I have been outperforming all my colleagues physically, skipping lunch, etc, without feeling like I’m pushing myself. I eat <25 net carbs a day, 70g protein and the rest fat (1700 cal - I feel full for a solid day at this caloric intake) . Get tons of dark leafy greens and eat a bunch of Avos and a good variety of meats.

Anyway, this past couple weeks I’ve been experimenting with longer fasting. I did a 33 hour fast, and broke the fast with a typical keto meal (maybe a bit more protein than usual, but vast majority was fat). I cruised right back into eating without any dip in energy levels whatsoever. It was seamless and awesome and if anything improved my performance on the job.

Then, I decided to try a 48 hour fast. That’s a sleep, a full working day, no food in the evening, another working day, then breaking the fast that evening. I felt absolutely incredible during that fast. Tons of energy.

On the last day I started to feel a tiny bit hungry. I knew I could have kept going without much of a problem and it probably would have faded away. But I had fun experimenting and figured I can always try a 3 day fast next week so I decided to break the fast.

I ate another keto meal. Maybe a bit more protein than usual, but negligible carbs.But basically a couple avocados, some bacon, some smoked salmon and steamed veggies with coconut oil…

About 20 minutes after I started experiencing the most absolute horrible feeling. I felt run down, lethargic, cranky. I was feeling great right before I ate. This feeling lasted for a solid two days. I was just so insanely tired. Stuck to keto still. I did some research and found some things about vit b1 and b5, sodium and water. I ate some nutritional yeast and some salt lemon water. I felt better later, but not nearly as good as I felt during the fast/before it…

Id really like to do these fasts again because they feel so good. But I don’t want to experience the refeeding hangover. It sucks, a lot. If I knew what caused it then I would be able to prevent it in the future.

Any advice would be greatly appreciated

Thanks guys,

(Carl Keller) #2

Hello and welcome Pete.

I would replicate the meals that didn’t affect you negatively after fasting. It’s reasonable to assume that the longer we fast, the more gentle we need to be when re-introducing food back into our bodies. I’ve heard of people that experience nausea after a fast breaking meal and that’s likely from low stomach acid and the gut mucosal layer being diminished.

Here’s a pretty good article on breaking a fast. Please note that some of the foods they suggest for reintroduction are not keto foods and I wouldn’t encourage those;

(Karen) #3

Hi Pete

Do you still have the same problem? Are you still fasting?

I often have the same problem, I can easily fast 16/18 hours a day and feel great every day,but if I do longer fasts like 24 hours, I feel great during the fast mainly low carb, but the next day once I eat I can feel very lethargic and low in energy and cranky.

Did you ever find any solutions? Or anyone else got any ideas,

Also I just seem to loose the same 3 pounds and regain it. Driving me mad!!!


What does this mean?


Did you eat before noon when cortisol levels are at their highest?

(Karen) #6

I didn’t really explain myself properly. I have a eating window of 6/7 hours a day. Usually from 11/12 -6pm. When I eat it’s usually for lunch a green leaf salad and salmon or chicken and homemade oil and spicy salad dressing. Dinner is roasted veg ( courgettes and cauliflower and peppers) and a protein chicken/ beef/ fish. A few days a week I have 3 rice crackers for lunch and cheese ( along with salad or veg).
So when I eat it’s low carb. I used to eat chocolate daily ( but been gaining peri menopausal weight over past 2 years about 1 stone ( 14 pounds). So now io not eat chocolate 2 or 3 times a week ( 3 Lindt chocolate balls(

I try and do longer fasts 2 days a week to try &loose a few pounds. So on those fasting days I will have a coffee at 7 am with almond milk
un sweetened. I do a workout ( I run 3 days a week average 5-7 km per run) and I do home workouts of weights twice a week for 20-30 min.
On fasting days I drink water during workout and after about 11 another coffee and almond milk.
My ketones only really rise after a longer run ( not so much the weights).
My ketones on a normal intermittent fast day in morning are .1/.2 when I wake up and they only get to about .7/.8. To raise them higher I need go for a run ( will be .6 after run and may go higher in the avo if I keep fasting to about 1/1,2)
On fast days more sparkling water and I keep busy and I feel good. On some fasts I will have another coffee ( even decaf (around 3 pm. Some with 2 small Keto fat bombs homemade with coconut oil & 85%dark choc. Other times I try keep going till dinner.( and not have the Keto balls) So make it 22 hours fasting. Will have a low carb salad green and salo. So during thus fast I feel pretty good.
I do put salt on my food as I like salt ( but perhaps not enough?)

I dont always sleep as well so may take some melatonin. Next day I only eat again after morning workout and coffee. So could be 11/12; but once I eat I do feel very drained and lethargic, I often feel cranky a good part of the afternoon, just tired and drained.

I can’t see how I feel so bad, I feel it nearly cancels out all the good part of the fast and the 2-3 pounds I loose just seem to come back on, even though I am watching what I eat. It’s soo frustrating!!!

Any help with raising my ketones? As even though I get into Ketois and have followed low card diet and been in mild Keto sis (.5 ) quite a lot I don’t seem to loose weight/ burn fat. I know mt clothes are not looser, if anything my tummy is getting larger ( hormonal weight gain peri menopausal (
Or to help with tiredness and lack of energy after a fast ( following day).
Many thanks in advance

(Han Qi) #7

The exact same thing happened to me. Felt fine after 1-day fasts. Tried a three day fast for the first time, felt fine during the fast, but about 20 minutes into my first meal breaking the fast, I felt this weight over my entire body, feeling sick and have been sluggish and unmotivated to do anything at all for 2 days now.

After resuming eating for 2 days now, I’d say I’m still very tired and sleep doesn’t seem to help.