Do you recommend going in and out of ketosis?

February 25 2018 by , medical content by in Dr. Jason Fung, Intermittent fasting, Keto, Ketosis, Low carb & high fat, Q&A

What do I need to know about exercising while doing extended fasting? How much salt should I add to water when I’m fasting? And do you recommend going in and out of ketosis?

It’s time for this week’s Q&A about intermittent fasting and low carb with Dr. Jason Fung:

Exercising while fasting

Is there anything I should bear in mind regarding extended fasting and endurance training? I’m looking at starting some extended fasts of around 36 hours, but I will also be exercising quite heavily as I’m training for a marathon. Any advice would be really appreciated.

Chris

There is a period of adaptation, about 2-3 weeks to get your body used to exercising while fasted.

Dr. Jason Fung

Water fasts and staying hydrated

Hi Dr Fung,

Do you have a recipe for how much salt to add per one liter of water, for a person to drink while on a water fast to maintain hydration and electrolytes? Every person drinks a different amount of water each day so the question is if a person only drank this salted water and no other liquids.

Thanks,
Rachel

There is no single right answer. Some people don’t use salt at all. Others get dizzy if they do not take supplemental salt. The kidneys have an extraordinary ability to retain salt in the the event of sodium depletion. For shorter fasts (24-36 hours), it is likely not necessary to supplement.

Dr. Jason Fung

Going in and out of ketosis regularly?

Is it necessary or recommended that you switch out and into ketosis again on a regular basis? Online I read that some experts advise that, in order to maintain insulin sensitivity. For women I even read about a high-carb “week” during the menstrual cycle, altered with a ketogenic diet in the other 3 weeks. Or 5 days keto, 1 day fast and 1 day feast, with higher carbs.

I watched many videos on the dietdoctor website now (love it!) But have not come across any such advise yet.

Mirjam

Personally, I think it is beneficial to switch things up every few weeks, too, although most evidence is anecdotal. There is one small study MATADOR, that suggests this is true. In this study, alternating periods of calorie restriction with normal diets seemed to be better than continuous dieting. The same may hold true for ketosis for some people. But there is no evidence to suggest one way or the other, and different people will respond differently. Some people struggle to get back into ketosis once they go out, some experience cravings they can’t control, and others move back and forth with ease. The key is knowing which group you are in. Hopefully we will have data about this in the near future.

Dr. Jason Fung

Q&A videos

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Top Dr. Fung videos

Diet Doctor Podcast #64 with Jason Fung
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Why low-fat diets don't work — Dr. Jason Fung's diabetes course
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Does a low-fat diet help with reversing type 2 diabetes? Or, could a low-carb, high-fat diet work better? Dr. Jason Fung looks at the evidence and gives us all the details.
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Dr. Fung's fasting course part 5: The 5 top myths about fasting – and exactly why they are not true.
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Part 7 of Dr. Jason Fung's diabetes course
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Dr. Fung gives us a comprehensive review of what causes fatty liver disease, how it affects insulin resistance and, what we can do to reduce fatty liver.
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Dr. Fung's fasting course part 4: About the 7 big benefits of fasting intermittently.
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Intermittent fasting for beginners

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Earlier Q&A

Intermittent fasting Q&A

More with Dr. Fung

Dr. Fung has his own blog at idmprogram.com. He is also active on Twitter.

Dr. Fung’s books The Obesity Code and The Complete Guide to Fasting are available on Amazon.

35 comments

1
Ed Wilcox
February 25 2018
.."the same 'probably' holds true for Ketosis?" What kind of professional medical advice is that? I suggest you do your research before providing an answer, or don't provide an answer.

Replies: #7, #23
2
Lance Brown
February 25 2018
"I think it is beneficial to switch things up every few weeks, too, although most evidence is anecdotal. "

Valter Longo's research is not anecdotal.

Define beneficial...
3
Deborah Kendryna Johnson
February 25 2018
I am a Keto person I it helped me get off a platue change my metabolism. I have now kept off for over a year and I do switch up I believe in listening to my body. I am very grateful for Keto and I switch to Paleo and very occasionally I have my indulge days. Grateful for Keto and Paleo I am healthier than ever before.
4
Jan
February 25 2018
My gosh people... Just eat a well balanced diet and never get full... forget all the fads!!!

Replies: #8, #26
5
Cam
February 26 2018
You should never ever exercise during a fast besides something light. I'm not sure if this is an actual licensed medical practitioner or not. But intense exervise during a fast is extremely dangerous.
6
Allen
February 26 2018
Thanks for the advice Jan, but trust me when I say that a lot of people on here had done what you said and got NOWHERE.

And ketogenic dieting is NOT a fad. Low-fat diet is a fad, vegetarian diet is a fad, eating 11 servings of grains and massive amounts of sugar and treating a calorie like any other calorie is a fad. They have all failed.

Some of us, myself included have lost lots of fat and been healthier than we have been in years. Personally i dropped 80 pounds, I am off all my HBP meds and my T2D is gone.

So please, spare the advice that everyone that suffers from obesity has heard a million times before. It’s amazingly disrespectful to think that they haven’t tried that old saw before.
7
Reply to comment #1 by Ed Wilcox
Ethan Asamoah
February 26 2018
He clearly said before answering most of the evidence is ancedotal with exception of 1 small study he pointed to
8
Reply to comment #4 by Jan
Jason
February 26 2018
Lol you don't know about keto if you think it's a fad. So why are you here troll? No other diet saves children from epilepsy, kills senescent cells, reverses diabetes etc. You dumb people are so prevalent. No wonder we got Trump.
9
Laura
February 26 2018
Lmaooooo Jason facts!!
10
Deb
February 26 2018
I want so bad to fast but my adrenal fatigue kicks my butt bad if I even put off breakfast s few hours ?

Reply: #33
11
Justin Lurker
February 26 2018
Jan, I've also heard an apple a day keeps the doctor away. Word.
12
sara
February 26 2018
I lost 30 pounds on a KETOGENIC diet. I feel and look better now than I did 15 years ago.
13
Anna
February 26 2018
I’m trying keto for a month but heart burn is really killing me. Taking PPI now and didn’t ever take it before but still now have horrible heart burn around the clock. How to stop it?

Replies: #22, #25
14
Patricia
February 26 2018
Anna, apple cider vinegar after each meal will get rid of heartburn. You can mix 1 tablespoon with two parts water if you can't take it straight up. I would quit all acid reducers before starting the cider vinegar though. Hope that helps.

Reply: #24
15
Escapology
February 26 2018
The moment when you realize that reading the comments answers more questions than the actual Q&As...
16
Naomi
February 26 2018
For those who thinks Keto is a fad, maybe you have not tried it at all, I have tried so many fad diets and they all fail as they are not sustainable, keto is sustainable . I have lost 56 lbs and I am no on my normal weight of 113 lbs at 5'2". Thank you to all the doctors and experts behind dietdoctor. More power to you all
17
Oscar Chalupsky
February 26 2018
I do normal training in the fasted state. I train about 2-4 hours a day. I have done many 24 and 48 hour fasts and 2 x 4 day fast. Will try do a 7 day fast next.
18
Marilyn
February 26 2018
I had open heart double bypass would i prevail on a ketogentic diet??
19
Rick
February 26 2018
Jason... I have a great respect for many of your postings, and I have a specific distaste for trolls, but I am disappointed with your reference to Trump. I don't see the connection with keto. Unfortunately, you got sucked in and the troll won. For what it's worth, my wife is a functional medicine physician, and I have recently been forwarding some of your postings to her. They are very informative. I have personally benefited from keto. Also, I think Trump was a far far better choice than the alternative, despite his flaws, and I don't consider myself "dumb".
Rick
20
Wade
February 26 2018
Completly useless Q&A that was Dr.s really know nothing about keto diets. I’ve lost 60lbs and never felt better in my life on keto in 1 year. My Dr had to ask me all about it. Anyone saying it’s a fad is completly false it’s a lifestyle for me and many other people. I will never go back to how I use to eat. However I would like to try one week of eating healthy carbs every few months. Wondering if anyone else tried this?
21
David
February 26 2018
For myself Keto-OS has help me loose 18 lbs as of about two months. My appetite has changed, gotten to where I can say no to sugars and fats on my meals. I use Keto-OS every day and work out 2 to 3 times a week. My question is do I have to stop taking Keto-OS every now and then for it to be more effective? And how long are this breaks for ?
22
Reply to comment #13 by Anna
Belle
February 27 2018
read "great taste no pain" diet info.. then apply info to keto.. it will stop.. really!!! once you understand the info its a whole new life
23
Reply to comment #1 by Ed Wilcox
Me
February 28 2018
Ummm ... it's NOT professional medical advice because they can't give professional medical advise over the internet. Chill pills are what you need.

.."the same 'probably' holds true for Ketosis?" What kind of professional medical advice is that? I suggest you do your research before providing an answer, or don't provide an answer.
24
Reply to comment #14 by Patricia
steve bromley
February 28 2018
patricia -

try miso. it works for me...

light miso, dark miso, dissolved in hot water...

it has not interfered with any aspect of fasting (now late in my third week) or my keto diet...

good luck!
25
Reply to comment #13 by Anna
Carolyn
February 28 2018
Hi Anna, I had to stop all things coconut, it gave me terrible heartburn! Sad because I love the taste. Also ACV should help sort it or even some lemon juice in a glass of water.
26
Reply to comment #4 by Jan
Filipe Jorge
May 2 2018
Hi Jan, doing what you sad create in one year a Fat leaver disease, eating every two your is not a god advise, in this moment I'm doing Keto a IF for the last 7 months and I revert the leaver problem, I lost 9kg, 10% of visceral fat, and my analyses are amazing, so I recommend before talking or writing anything about Keto and IF read first, Google, is the best place to search.
27
ChrisI
January 18 2019
I did keto for 6 months and lost 25 lbs... then plateau'd I took a break for a month and started 16-8 Intermittent fasting alternating 1 week on keto and 1 week low - carb . The Variety makes it easier to keep going , I get great results on my keto weeks and get just enough of a break my low carb weeks to stay motivated and moving forward. I honestly think the intermittent fasting would work on it's own.. but I am trying to maximize the results by eating clean.
28
Julie
January 19 2019
How much water should I drink on keto? I read somewhere that an ounce of water for every pound of body weight and another that says something like '0.04X kg of body weight' that is how many liters to drink. and then one of the moderators on facebook page says there is no science to say that.
But I keep seeing it.

Reply: #29
29
Reply to comment #28 by Julie
Kristin Parker Team Diet Doctor
January 20 2019
Drink to thirst. Hydration needs vary based on weather, humidity, natural fluid in your foods, temperature and more. Drinking too much water can flush electrolytes, making keto flu worse.
3 comments removed
33
Reply to comment #10 by Deb
Dan
February 1 2020
Deb: this is not medical advice, but you could try an intermittent fast if longer fasts don’t work for you. Eat a paleo breakfast and dinner. There are studies that suggest you receive some of the health benefits of longer fasts even by going 10-12 hours between meals. Take a walk or do some negative resistance weight training during your lunch break.
34
Kevin Marshall
February 7 2020
I was diagnosed with type 2 diabetes told to get used to taking medicine for the rest of my life . Watched Dr. Jason Fung podcast got interested in keto and seemed logical . have lost 25 lbs diabetes has reversed itself and I feel great my doctor is watching me and very interested in the results . Once you get keto adapted fasting is easy no cravings I fast 16 hours between dinner. I feel great and my friends say I look great. reference Dr. Jason Fung, Dr. Eric Berg, Dr. Paul Mason, and Dr OZ. Watch there podcasts and learn what you can it wont hurt.
35
Audrey Rose
February 23 2020
I'm having a problem on staying in ketosis. I fall out during the day. I monitor my micros and hve a blood monitor. I really cud use some advice on wht to try.

Reply: #36
36
Reply to comment #35 by Audrey Rose
Kerry Merritt Team Diet Doctor
February 24 2020

I'm having a problem on staying in ketosis. I fall out during the day. I monitor my micros and hve a blood monitor. I really cud use some advice on wht to try.

You may find this article helpful! https://www.dietdoctor.com/lose-weight-by-achieving-optimal-ketosis
37
Georgina
September 21 2020
I started this journey just over 2 months ago. I have enjoyed all the recipes and the supportive community but unfortunately I have become quite unwell with this WOE and cumulated with a stay in hospital with ketoacidosis ( I'm not diabetic). So my question is... What now? My doctor is insisting that this WOE does not personally agree with my body but I do not want to back to eating carbs, or should I say overeating carbs! What is a healthy level of carb intake without taking my body into ketosis? Has anyone else experienced this? I realize that medical advice can not be given. Just asking for others experiences and opinion. Thank you.

Reply: #38
38
Reply to comment #37 by Georgina
Kristin Parker Team Diet Doctor
September 21 2020

I started this journey just over 2 months ago. I have enjoyed all the recipes and the supportive community but unfortunately I have become quite unwell with this WOE and cumulated with a stay in hospital with ketoacidosis ( I'm not diabetic). So my question is... What now? My doctor is insisting that this WOE does not personally agree with my body but I do not want to back to eating carbs, or should I say overeating carbs! What is a healthy level of carb intake without taking my body into ketosis? Has anyone else experienced this? I realize that medical advice can not be given. Just asking for others experiences and opinion. Thank you.

Please continue to work with your medical provider. You may find a more moderate low carb menu to be a better option. For many people, 30-50g net carbs works well as a moderate low carb option.
https://www.dietdoctor.com/how-low-carb-is-low-carb

Here are our moderate low carb meal plans.
https://www.dietdoctor.com/low-carb/meal-plans

Exercising while fasting

Water fasts and staying hydrated

Going in and out of ketosis regularly?

Q&A videos

Top Dr. Fung videos

More

More with Dr. Fung

35 comments

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