Little bit confused on when it's ok to start fasting

(Cindy Ward) #1

I know it’s a bit of n=1, but would still like advice. I started keto for 2 weeks, took off 3 days around Thanksgiving (but still moderated pretty well), so I guess I’m close to finishing up my 2nd “new” week.

I don’t have any trouble going 20 hrs between meals. I don’t enjoy breakfast, so it’s easy for me to go from dinner one night to dinner the next, but I’m not really doing that as a “fast,” as in, a planned “no eating” window. It just happens. On other days, if I’m hungrier, I’ll eat 2 meals so I’m not OMAD every day, but just listening to hunger signals.

For whatever reason, committing to a 24-36 hr fast kind of intimidates me (because I’m afraid I can’t do it), but it’s something I DO want to do. So the first time I fast, I want to set myself up for success. If that means I should week until I’ve been doing keto for 6 weeks, I can wait. Or if waiting doesn’t matter and just trying it is more important, then I won’t wait.

Anyway, would love to hear advice and suggestions from experienced fasters.


I’ll tag @juice :slightly_smiling_face: He fasts & is good with the clear advice.

(says keto isn't complicated. Sorry, but it just isn't.) #3

Droll :slight_smile:

Fast when you feel like it’s a good idea. Don’t fast if you don’t think it’s a good idea. Eat plenty at meals when you’re not fasting. Take plenty of salt especially when fasting.

Check in on the monthly fasting thread, some great people over there who are really helpful.

But remember, fasting is just a tool in the toolbox, not a method of collecting internet keto points :slight_smile:

(Doug) #4

This means a lot, Cindy. I was used to just eating once a day, and plunged right in with the fasting, without problems. Everybody is different, and for many people it pays to wait until the body is better at burning fat, i.e. is ‘fat-adapted’ (and the insulin levels have come down some due to eating very low-carb).


See - the good, clear advice :smile:

(Cindy Ward) #6

I did (read a lot of the monthly fasting thread). :smiley: Not trying to get internal keto points, but I grew up with “you must eat 3 meals per day” mantra being pushed onto me. I’m absolutely LOVING eating only once or twice per day and feeling like that’s a healthy thing. I used to say that if I could find a way to just not eat, I would…but, of course, hunger always said differently. So fasting is very appealing to me.

(Cindy Ward) #7

Thanks, Doug. That helps! I’ll probably wait until next week…it’s hard to fast on the weekends when hubby is home more. It seems like he eats every 3-4 hrs…well, he does :wink: and his meals usually have a part 1, 2, and 3. So it’s easier for me when he’s at work during the day. I’m thinking about just 24 or 36 hrs at first…but I’m very curious to try 3 or 4 days.


This is key, but also to add – you might start out thinking it’s a good idea and even get a fair bit of fasting time in. Then you do start to feel rough or really hungry. Don’t feel bad, especially your first few fasts, about stopping and going and having some food. There is no competition, it often feels like people are seriously trying to get the longest fast they possibly can (OMG world record!!!) yet simultaneously saying they don’t feel great and are ploughing through it.

If you do fast and enjoy some of the side effects, it takes time to get it right and find out what works for you. Pull the plug when it doesn’t feel right.

(Cindy Ward) #9

Thanks! I have a little bit of experience with fasting (not by choice) when I had a LapBand. There’d be times it tightened up so badly that I couldn’t do anything but sip water to stay hydrated until I could get a doctor’s appointment (sometimes up to a week). I remember actually liking that in a way, but I didn’t have a CHOICE either…just had to make the best of the situation. The band also seriously curbed hunger, so that wasn’t an issue.

(says keto isn't complicated. Sorry, but it just isn't.) #10

All of these things, so much.

(Doug) #11

Cindy, if you can go 20 hours, you already have a big advantage over many people, for whom there are often problems with hunger around the 18 hour mark. By then, the stomach will have been empty for a while, and the small intestine will also be pretty well done doing its deal, so the body is into the sensing-less-nutrients thing pretty heavily. Quite a few people time their fasts so they sleep through that period around 18 hours.

It’s also common for people to say that the second day is the toughest. I agree with this to an extent. Will also say that a given fast may feel different from the last one, or from one’s fasting experience in general. I think we never really know. I got slightly cold feet on the third day of my first fast, but never again during 20+ more fasts. There will be ups and downs - it doesn’t really hurt to end your fast if you’re “just not feeling it.” There are more days coming and more fasts to be had.

One thing that does keep me going when fasting, even if I’m not feeling great, is the knowledge that I am doing something really good for myself.

(says keto isn't complicated. Sorry, but it just isn't.) #12

All these things too.

(Cindy Ward) #13

I read somewhere (Was it Dr. Fung’s book?) that they never ask patients to do “just” a 2 day fast. Their reasoning is that, since it’s usually the hardest day, why go through the toughest day and then stop? So it’s either 36hrs, 42hrs, or 3+ days. I think I remember that right?

(Doug) #14

Makes sense to me, Cindy.

Dr. Fung is currently big on the repeated 36 or 42 hour fasts, for sure. There are different reasons for fasting - weight loss, hormonal reset and healing, autophagy, immune system regeneration. I’ve not had immune system problems, but I’m very interested in autophagy and definitely need the rest. :slightly_smiling_face:

We certainly get better at fasting over time, and the more we do it.

(John) #15

36 hours is just one full day plus the 8-hour sleeping window. You are skipping 3 meals in a row. 24 hour fast is skipping 2 meals in a row.

Here are some of Dr. Fung’s comments if you want to review them.

Note his warnings in both links.

(Cindy Ward) #16

I need most of those, too. Not so much immune issues either, but weight loss for sure. I’m also really tired of joint pain…waking up in the am feeling like I need to shuffle for the first 30 minutes before things start moving again. I have noticed, though, that that is MUCH less after just a week of low carbs.

(Cindy Ward) #17

Luckily, I take no medications. When I was 40, I was very close to needing several medications…which promoted WLS. I wish I’d known about a ketogenic diet (other than the doom and gloom I seem to remember hearing) back then. Could have saved myself a chunk of money and some other problems. It did, however, help me to have almost a decade of at least closer to normal weight.
So anyway, I don’t think I’ll have any real trouble fasting, but I’ll certainly stop if I start feeling sick.

(says keto isn't complicated. Sorry, but it just isn't.) #18


(Eric) #19


I grew with 3 meals a day and weekend nights parents would go out to party and play bridge and leave us with the fixings for cream cheese dip and a lb of potato chips. And we ate it all.

I’m long past the chips but the 3+ meals a day has me eating when I’m not hungry. So I do IF 18/6 and OMAD (22/2) whenever I can. I love eggs and bacon so some days I fix scrambled eggs and bacon and take that to work for lunch. Lately I have been trying to get more omega 3 in so I eat sardines or salmon for lunch with a leafy green salad.

But on days when I eat breakfast in the morning I feel compelled to eat lunch and then I feel miserable all day especially if I eat at the cafeteria at the University (where I work). So IF 18/6 & OMAD helps me feel better.

I don’t feel like going for 36 to 48 hrs yet but will soon, I hope.

Some days I plan on OMAD and after early am gym time I just know that I have to eat and I make that a 3 meal day.

Good luck, it is a journey.


I could add reams about my great experiences with fasting, and my failures. But I find it beneficial and will continue Extended Fasting regularly. And, I began fasting within the first two weeks of reading Dr. Fung’s offerings.

However, here’s another tip, timing.

As they say, timing is everything. Do not try to begin a long fast after eating late – such as after 9 p.m. for sure. Try to eat a big meal that ends at 6 p.m., then fast. 7 p.m. is OK too. The thinking is that at 6 p.m. you will be full until bedtime about 4-6 hours later. You sleep about 8 hours and wake up having fasted 12-16 hours already. Also, most people do not wake up hungry and many find it natural to skip breakfast. Again you are ahead of the game on the first day.

An idea I read and am about to try is to eat a very big meal of eggs and bacon between noon and 1 or 2 p.m. This very filling meal will carry most people through the evening and onto bedtime where the 8-hour sleep trick again does its work. And you wake up just a few hours shy of a full-day fast.

Now, after the 24-hour or so mark is when the test begins and the importance of hydration, salt and electrolytes kick in big time. Apple cider vinegar is also your friend.

If you are accustom to 20 hours now, then I figure a 24 is just a long movie away and 36 will become 40 before you know it. As many say, try to keep busy, or sleep late if you can, or even take an afternoon siesta.

Now, 48 hours, for me, is when the bear attacks. Getting passed that hurdle is great. It takes some doing at times, mentally and emotionally – and you will develop your own tools and methods. But it can be done. Too many on here have done it. And when you wake up on the beginning of the third day at about 60 hours you will find that your determination and sense of success will carry you through most of the third day.

At or after 72 hours you may notice some body chills or even slight shivering. If you do, test your blood sugar. If you find it too low then simply call off the fast and go eat a bit. Eating will knock you out of autophagy (maybe) but you can resume the fast a little later and still continue to get the benefits of weight loss. And if you can continue into the long fast after a small meal or snack, then you have entered the area of the “snake diet” fast. Now, if you choose to continue to eat, then eat big and go regular keto.

If you did not hit the wall at 72-74 hours, then you are in for some smooth sailing physically. However the mental aspect still needs to be tamed. During the fourth day you need to decide if it is worth continuing the fast – eat something, or fck it, I am fasting on.

While some here fast for 5-7 days and beyond, I cut my long fasts at about 4 days. I once did 4.5 and once 5 full days and found little more benefit than doing a 3.5 to 4 day fasts But that’s me and these all were water-only fasts allowing only black coffee, unsweet tea, apple cider vinegar and occasional sip of dill pickle juice. No bone broth or the like. But again, that’s me.

Some of my 3-day fasts have been mostly for weight loss and I do include one teaspoon of heavy whipping cream once a day in my coffee.

As you can tell, there are a lot of ways to fast. Indeed, I am looking forward to next summer so I can try out my watermellon fast. :grin:

Oh, and yes, plan your fasts according to your social calendar. I start many of my fasts Saturday night after a big meal and then watch football games all day on Sunday.