Risks of Intermittent Fasting: Great for weight loss... Terrible for your adrenals, anxiety, sleep and just about everything else

Risks of Intermittent Fasting: Great for weight loss...terrible for your adrenals, anxiety, sleep and a couple of other things.

3/19/2017

Dangers of Intermittent Fasting: Cortisol and Low Blood Sugar

I usually only recommend intermittent fasting (IF) for my patients who are low carb/keto and not overly stressed/anxious. If my patients consume a fair amount of carbs and/or are stressed/anxious, I try to work on decreasing carbs and de-stressing first. I’ve heard nothing but great things about intermittent fasting lately, but everyone is failing to address the risks of intermittent fasting. Cortisol is pumped out in large amounts during the fasted state. We have this survival mechanism so, if our blood sugar gets too low or we’re stressed, we’ll pump out a bunch of cortisol (stress hormone) to turn the glycogen stored in our liver back into glucose to bring our blood sugar back up without having to eat anything. It also increases glucose to the muscles so we can fight or run away from whatever threat is present. This is a great survival mechanism and was great for the cave people because the cortisol would put them into fight or flight mode but now that food is in abundance and we’re not hunting anything down, it’s just contributing to our stress load. We pump out a bunch of cortisol when we’re low in blood sugar, when we’re stressed and when we have too much caffeine. We have enough stress in our lives, we don’t need intermittent fasting amplifying our stress levels.

Edit (Nov 12, 2018): Intermittent fasting is meant to be a stressor to our system in order for it to induce phagocytosis and regenerate our immune system. This can be a great thing when used in appropriate situations (under supervision of a trained professional, and while fat-adapted/keto). It's bound to worsen your symptoms if you are already stressed, anxious and eating a fair amount of carbohydrates. Intermittent fasting does have some benefits but just like any other therapeutic modality, should be done with proper guidance from a medical professional. If that medical professional denies that there are any risks, including the ones I list below, you need to find a different medical professional to help you through it. Rhonda Patrick mentions that our bodies were meant to be challenged and that's why IF helps, but in our current society our systems are already being challenged (stress, anxiety, external factors, insomnia, carbs, sugar, etc...) It's common for Intermittent Fasting to be a bit too much stress for an already over-stressed system. Please read some of the comments below for personal stories if you don't believe me.

Check out how similar the symptoms of low blood sugar are to stress symptoms.

Symptoms of Low Blood Sugar (Hypoglycemia)

Flushed cheeks or ears
Shaky hands
Weakness
Hangry
Anxiety
Irritability
Headaches and migraines can be triggered
Nausea, pit in the stomach, acid reflux, lack of appetite
Dry mouth
Fatigue
Sweaty palms
Hot flashes
Increased perception of pain
Low libido and sexual difficulties
Craving sugar, carbs or caffeine

Cortisol: Our brains don't know if we're stressed or low in blood sugar

When we’re pumping out excess cortisol, our brain has no clue if we’re low in blood sugar or if we’re in a threatening situation so it tells us to be stressed out and crave energy… 2 birds with 1 stone. If we’re pumping out too much cortisol we’ll eventually produce more adrenaline as a boost and that will cause extreme stress symptoms like uncontrollable shaking, vomiting, irregular heart rhythm, fainting, etc… If we’re constantly pumping out too much adrenaline it will eventually contribute to burnout as well.

I usually spend my second visit teaching this stuff to every patient because once they start eating adequate protein every 4 hours most of the symptoms mentioned above completely go away. It’s often the main cause of headaches, anxiety, nausea and sugar/carb cravings in most of my patients.

Intermittent fasting works for weight loss because any form of caloric restriction will lead to weight loss. There are healthier forms of caloric restriction that won’t set you up for burnout, exhaustion, adrenal fatigue and all the other complications of short- and long-term excess cortisol production.

Interfittent Fasting: Possible complications due to long-term excess cortisol

The complications of long-term excess cortisol secretion are:

Increased fat around the abdomen
Anxiety
Osteoporosis
Hormonal imbalances
Weakened immune system
Cardiovascular disease
Weight gain
Sleep issues
Blood sugar issues and diabetes
Thyroid issues
Digestive issues
Chronic fatigue
Fertility issues

Healthy weight loss without intermittent fasting

I usually recommend using an app/website like Myfitnesspal or Cronometer to track calories. If you use these they should be set to lose 1 lb/week and nothing more. If 3500 calories are equal to 1 pound, and you divide the 3500 calories by the amount of days of the week, we need to be at a deficit of -500 calories per day to lose 1 lb per week check out the math below:

Being at a deficit of 1000 and 1500 calories will yield the weight loss of 2 and 3 pounds respectively but at that significant of a deficit your body will adapt and expect that much for the rest of your life. Once you get to your goal weight and start eating like a normal person again your newly-adapted body will now start seeing that 1000 or 1500 calories as excess and start storing it at the rate of 2 and 3 pounds respectively. A deficit of 500 calories is nowhere near as shocking to the body so it doesn’t have to adapt. It sucks because it takes a lot longer to lose the weight but the weight will stay off in the end.

Based on my clinical findings and seeing the negative side of intermittent fasting, I believe our focuses on weight loss should be focussed more on reducing carbohydrates, increasing protein and fat, exercise, reasonable caloric restriction and proper sleep. If these don’t yield proper results investigating the thyroid is usually my next step to see if the thyroid is preventing weight loss. I get most of my patients to eat 10-20g of protein every 4 hours and it’s been helping their stress symptoms I mentioned above, leading to weight loss and having a healthy snack like pepitas or cashews before bed has been helping most cases of insomnia, as insomnia is usually due to low blood sugar causing increased cortisol levels at night. It’s difficult to sleep when we’re pumping out a bunch of cortisol and your brain thinks a threat is present, so stabilizing the blood sugar at night will help with that. Check out my article, “Why can’t I fall asleep or stay asleep”.

There are always two sides to every story. All the fuss about intermittent fasting seems to be favouring the positive side right now. I’m sure as time goes on we’ll be hearing a lot of the negative stories from the long-term complications of intermittent fasting. I think the craze is mainly due to celebrities endorsing IF, significant short-term benefits worth writing home about and articles sensationalizing laboratory findings to a stretch.

There are some populations who might benefit from IF but anyone considering it should be sure to work with a professional to guide them through it. There are a lot of important details that must be accounted for, in order to benefit. Intermittent fasting can be beneficial or detrimental. This article is intended to shine light on the possible pitfalls of intermittent fasting so it is used responsibly, I don't mean to totally discount it as a treatment. There are so many factors (personal health, frequency, duration, exercise, etc...), that I don't think it is a safe thing to do on your own without being properly assessed and guided. I also believe intermittent fasting is better-suited for those who are consistently doing the keto diet, compared to those who are eating whatever the heck they want and then fasting to make up for it. The former won't have as much blood sugar fluctuations and cortisol spikes as the latter.

Be sure to comment below, I’d like to hear your stories, opinions, etc… It’s a great thing to discuss right now.

Here are some other articles discussing the negative effects of fasting (Be sure to read both sides of the story):

Sincerely,

Dr. Justin Gallant ND
Hamilton, ON
www.DRJGND.com
Be sure to subscribe to my newsletter if you'd like to receive article like this whenever I publish them.

62 Comments

Scott Crozier

3/19/2017 10:28:41 pm

Great article Dr. Gallant! Very informative as IF is definitely a hot topic. Keep up the great work!

Dr Justin Gallant ND

3/29/2017 06:11:03 pm

Thanks Scott!
I appreciate it.

Judy McAuley

3/22/2017 03:40:04 pm

Thanks for the tips on the websites to track calories.

Dr Justin Gallant ND

3/29/2017 06:11:22 pm

You're welcome Judy!

Stephanie

5/17/2017 07:55:13 am

Great information! I have no problem doing a 16/8 fast and a couple years ago, I did it for a while. Surprising to me was that my A1C went up during that time so I stopped. I suspected that cortisol may be the issue but I didn't have any "symptoms" so I've been doing IF again for the last few weeks. This time, my sleep has been affected.
I'm going to give up on IF and use your tips to shed these 10 pounds. Thanks for this article!

Dr Justin Gallant ND

5/17/2017 09:10:10 am

Thanks Stephanie!

Sounds great!
There are a lot of great ways to shed that 10 pounds that are not traumatic to the system.

Thanks for reading!

Jenny Soto

6/21/2017 08:31:36 pm

I'm missing you out here in NB so I'm reading up on your blog to get my information fix! Such great advice. And timely for me too as I was thinking of quick fixes to get rid of this baby weight that's sticking around.

Dr Justin Gallant ND

6/23/2017 07:37:50 pm

Hey Jenny!

Thanks so much!
I started taking Fridays off so hopefully I can publish more content.
I have a lot of juicy articles waiting to be finalized but never have the time these days.

Nice to hear from you!

Alan

10/28/2017 10:06:33 pm

SPOT ON. Been struggling with stress for more than 15 years. Intermitent fasting has made things worse. What trully works is liatening to your body and REDUCE simple sugars till none. Consume fruits and mind your exercise too. Diet is 80% of weight loss but exercise is important too. I went keto and fasted and went horribly wrong. Because of the adrenal fatigue. D
Whatever works for others won't work for everybody

Dr Justin Gallant ND

10/29/2017 07:20:07 pm

Hey Alan,

Thanks for writing in!
Very well said.
It's great to hear personal accounts.

Piotr

11/15/2017 04:01:23 pm

Shame I didn`t read your article before I started IF. I was doing 16/8, no calorie counting, just eating whatever(fairly clean). When I dropped the diet after 3 months, because I haven`t seen any positive results. After I got back to eating breakfasts and more food, then I started feeling symptoms of anxiety, lack of sleep, generally I was in mess. My endo told me that I possibly have a pancreatic cancer, so that didn`t help for anxiety. Luckily he was wrong and my guts and other organs are fine. What help me to get back on track is gym workout, weights + cardio and of course the solid diet. Five meals a day, all with protein, just the last one without any carbs just to not trigger the insulin. That was my main problem - insulin. It put me in a reactive hypoglycaemia. I`m still going to have a glucose test in Jan 2018 but I believe the levels of insulin any other hormones are getting back to normal. What is most important, I sleep like a bay now :-) Great article. Again, shame I haven't read it earlier.

Dr Justin Gallant ND

11/18/2017 02:33:17 pm

Hey Piotr,

Thanks for sharing your story!
Hopefully others will see it earlier on their journey.

Anna

1/18/2018 03:48:08 am

This is a great article and exactly what i experienced!
Intermittent Fasting can be incredibly dangerous, especially for women!
I did everything wrong you could ever do wrong for only about a month and my life crashed into pieces from one day to another!

One day last year i decided to become even more "healthy" (i always had a good nutrition, did exercise couple of times a week ,...) but i wanted more. So i startet intermittent fasting with only 2 big meals a day (in a short 4 hours window), did crazy amounts of high intensity cardio every day (no rest days) and drank 4 cups of coffee (because Intermittentfasting Gurus tell you to push your body).

This went more or less well for about 4 Weeks, from one day to another i suffered from extrem insomnia, fatigue during the day, incredibly bad skin for the first time of my life, and after 4 more weeks of these symptoms i fell into the worst depression i ever expercienced. I couldn't think or speak anymore and had to quit my job. This was 8 Months ago, i'm still recovering and not working again, the slightest physiological stress knocks me out for a week.

In the End, the whole thing might have cost me a year of my life.
One year without social events, holidays, work, ... any joy and activity at all!
Please think of this article and my words when you think you need to push your body although it does everything it can for you.
Take care & lots of love from Germany, Anna

Dr Justin Gallant ND

1/21/2018 08:35:49 pm

Hey Anna,

Thanks so much for writing in.
I hope others read your story so they don't have to go what you went through. I've heard similar stories way too often.
Hopefully your recovery doesn't take too long.
If you feel like you need help recovering definitely reach out to a naturopathic doctor. There should be some who did proper training in Germany.

chevy

1/20/2018 02:20:31 am

going through this now..... did intermittent fasting - ate only in 4 hour window for about 2 weeks.... tonight i just couldn't take the insomnia and i ate a very big meal...... big mistake. heart palpitations, anxiety, dry mouth..... I'm not sure what is going on.... had to take a xanax to calm down... what is happening?

Brenda link

1/26/2018 01:14:11 am

I take natural thyroid for my hypothroid condition and am constantly researching ways to lose my excess weight. I tried the IF and my sleep pattern was dreadful. Waking with an irregular fast beating heart and feelings of panic. I have stopped IF and started taking taking Ubiquinol and Ashwagandha and my sleep has improved remarkably.

Dr Justin Gallant ND

1/31/2018 08:35:35 am

Hey Brenda,

Thanks for sharing!
Glad to hear your sleep has improved!
It's difficult to lose weight if you're not sleeping well.

Amanda

2/5/2018 04:56:07 pm

I just got done reading both of Dr. Fung's books regarding fasting and was looking to try it as I've struggled with pre-diabetes all my adult life. Though up until now, I've never fasted longer than 16 hours, I would have to say that times when I don't snack and wait at least 12 hours between meals my blood sugar is far more stable. It seemed at least for my body, eating frequently was more like a drug just treating the symptom rather than treating the problem and helping my body fix itself. This article leaves me a bit confused ... is there a tough period in the beginning that your body eventually works through?

Brent

3/12/2018 09:46:30 am

Eating in an 8 hour window is dangerous?

Breakfast at 9 am lunch at 12 and dinner by 5 pm. I did that my entire life. All I did was stop snacking before bedtime.

Is this dangerous?

Dr Justin Gallant ND

3/15/2018 03:47:51 pm

Hey Brent,

Thanks for the question.
I wouldn't call it "dangerous" but it can lead to all of the symptoms that I've mentioned above. It'll be a lot worse for you if you have a mainly carbohydrate-rich diet, have anxiety, insomnia, burnout, etc...
We're all different, we have to find what works for each and every one of us. This article was to shed light on the possibility of it causing adverse health effects, since most other articles written about IF are not acknowledge the risks.

Hannah

3/14/2018 10:02:16 am

Very helpful thank you. Actually been a big fan of intermittent fasting and didn’t want to accept it makes my anxiety worse but I know it’s the culprit so I’m stopping it totally. Great read and thank you

Dr Justin Gallant ND

3/15/2018 03:48:38 pm

Hey Hannah,

Thanks for your comments and kind words!

Anna

3/17/2018 09:35:47 am

Thank you for this informative article. I have never been a night eater and have experienced bouts of insomnia my whole adult life. I started IF about a month ago and now eat in an eight hour window, which is four hours less than my normal window. I'm losing weight but it's exacerbated my insomnia. Last night I had heart palpitations, which I've also experienced before IF. I'm going to take your advice and eat cashews before bedtime to see if that helps. If not, I guess I'll drop it. BTW, I'm 57. I've read that IF may not work for menopausal women. Thanks again.

Jacob

4/4/2018 10:58:45 pm

My opinion is that this article diminishes your credibility. Number one, I feel IF should never be used for weight loss. You are already headed down the wrong path if you're using it for weight loss. That's the first glaring issue with your article. IF should be used a tool in a healthy lifestyle. Weight Loss will likely be a derived benefit, but should never be the goal with IF. Number two is that you say it's "terrible for everything else.". We're in the age of Trump and I haven't heard such an inaccurate statement in a while. Grabbed the attention of readers though. Good work there...I guess.

Dr Justin Gallant ND

4/6/2018 06:22:01 pm

Thanks for your opinion Jacob!

It's a tad salty for my liking but perhaps the cortisol and adrenaline production caused by intermittent fasting is contributing to your negative tone? haha

Intermittent fasting is being used for weight loss everywhere I look.
I agree with you that it should not be used as a weight loss tactic. It might be acceptable for those who are keto-adapted but for those who aren't, it definitely poses risks. It sounds like it's working for you, based on your passionate comment, but we are all different. My goal was to raise awareness of it's possible pitfalls, since everyone and their brother are doing it without proper guidance or education.

I wrote, "Just about everything else" leaving room for exceptions.

There are already a few comments by people who didn't fair so well with IF, so this article can't be anywhere near as inaccurate as the "fake news" you're comparing it to.

4/13/2018 08:51:26 am

Humans have fasted for thousands of years and the evidence is conclusive, "doctor."

Let's not forget that 1) people who don't have discipline and are too food and comfort addicted don't want to see the time honored tradition of fasting or anything that requires effort (oh no! you'll go into starvation mode! oh no you'll ruin your metabolism! oh no you need 18 small meals a day to be healthy! Honestly, where do people come up with this stuff when all conclusive data and empirical evidence says the opposite?)

and 2) sadly doctors are informed mostly of the benefits of alternative medicine and methods that actually work because they're employed by a system run by pharmaceutical companies who can't profit from people actually being well (and contributing to society and dismantling a system with a GDP that actually increases when people are sick.) It's not complicated stuff. Try OMAD and see how your health, focus and productivity improves and ignore people who don't have the balls or strength to actually change their lives.

Dr Justin Gallant ND

4/13/2018 11:35:19 am

Humans also used to live a third as long as we did, "AM"
They also didn't have vitamin K injections at birth and had brain bleeds.
They also used heroine and cocaine in medicine.
They also didn't wear shoes and got foot infections and died.
They also didn't have antibiotics.
Should we continue these traditions as well?
What separates fasting from these things?

What I'm saying is based on physiology as well as clinical experience.

You can't just say all conclusive data and empirical evidence says the opposite just because it sounds like it makes you right.
Have you looked through ALL of this data and empirical evidence?

You've rummaged through pubmed and haven't found one article that claimed there might be a negative effect?
That must've taken you a long time if you have.
I don't think there's anything out there that they've been able to prove 100% as you're suggesting. If there is in this case, please post whatever you can and I'd love to read it.

I'm a naturopathic doctor, we are far from being employed by a system run by the pharma companies. That doesn't make any sense.

I've had a lot of patients come in who have tried OMAD and it ended up causing insomnia, anxiety, panic attacks, after a while.

It's okay to have different opinions.

4/10/2020 09:11:19 pm

Agreed with AM. 16:8 is waste of time. 20:4 and 23:1 are best. Beginning fasting comes with withdrawals for a week. After that it’s great. Dairy protein is poison. Reduce gluton. Eat complex carbs and veggies as staple foods. Limit meat. Weight train after meal. 5-10min cardio after dinner.

Lorraine link

4/12/2018 04:38:28 pm

Thank you Justin for your article. I have struggled with energy depletion ups and downs with adrenal burnout over the years. I have a naturopathic physican who recommended IF. I began doing it 16/8 with my husband. I cook really healthy and we eat LOTS of dense salads, good clean protein and healthy fats. I also am pre-diabetic which I am looking to reverse. While my husband has been thriving on the program, I have no cravings, blood sugars have been better, I have lost 10 pounds, but am more tired. I increased my good supplements including organic green drink, ACV coctails. I am already on natural thyroid hormones. But I think the IF including 3 two day fasts in the last month and a half, have taken a lot from me. This is my query.. It is true that in the past people did not have access to food all day and night and they were healthier. They were not over fed as we are today and under nourished. Fasting is in the bible all over the place as a natural way, not unnatural. Feasting has no meaning if we are always feasting. Feasting makes sense with some type of fasting. There is a proper place for it.. Perhaps the problem comes in when there is an already damaged metabolism. So, I am having my adrenals tested through Dutch test, and all my other levels tested. I want a tighter check on what this is giving and taking from my body. I wanted to stop food binging and addiction as gluttony seems to be societies most acceptable "sin". I want food and eating to be a healthy, natural part of life. I do not want extremes, but balance. So I am going to have to see what that is for me even if it differs from my husband. It is not a competition, but individual. So I will carefully weigh the benefits and contraindications and move toward balance. Our body's have great wisdom to heal itself but we must listen carefully and have the correct information. Thank you, again

Dr Justin Gallant ND

4/13/2018 11:40:52 am

Hey Lorraine,

I love this response!
It's debatable whether they were healthier back then as we can't really compare blood tests or medical records.
Balance is definitely key!
Usually extremes are not sustainable and have some negative consequences.
Good luck on finding what is right for you!
I'm glad to have offered another side of the story as some patients come in thinking their crazy because IF is working for their husband but not for themselves.

Thanks for writing in!

Nancy Hendrix

4/24/2018 09:43:37 am

I've tried intermittent fasting (4 wks now), I'm also hypoglycemic. Started having headaches, stomach cramps and other symptoms that you described on your page. This convinced me I needed to stop and just watch what I eat. BTW I am 71 years old and do not want to get big and fat at my age. I am 5'1" so weight is important to me. Thank you for the informative article.

Dr Justin Gallant ND

4/25/2018 04:50:47 pm

Hey Nancy,

Thanks for sharing your experience!
Hopefully you find something that works for you!

Lorraine link

4/24/2018 11:15:08 pm

Justin, I posted last week and I am amazed at the changes that took place in the last week and a half. After I posted my comment that I had to re-evaluate IF due to fatigue, I had to stop IF. My body took a crash and I spent the weekend in bed. For me, prior, I had a sense I was bullying my body to do MY bidding instead of meeting it's personal needs. It was saying, this isn't working Lorraine. Very high blood pressure, temperamental blood sugar, feeling tired and unwell. What I did is decide to be kind to my unkind past that's still locked in my body. My body has a memory of all its been through in the past. All my late nights in my youth missing sleep, all my pushing, pushing my body, like a slave driver. I really needed to apologize because for goodness sake, my body has certainly tried to take care of me, even when I did not let it. So, I added back a small morning meal, kept lunch and dinner added L-Glutamine for the gut, bone broth, added ashwaganda, Rhodiola, Berberine/Pqq all adaptagens and what an amazing difference. Blood pressure normalized in a week, fasting blood sugars are in the 80's, and I am feeling a sense of real homeostasis entering back. For me, my body really needed mitochondria support and gut support. And adding a little gentle morning meal with supplements stopped the cortisol raging. I allow myself extra rest and now that I am giving my entire system what it needs. The next progression will lead naturally to shed extra weight. I am showing increase keystones now then before even though I added the morning small meal. How about that. I found the book "Parables of the Flesh" to be enlightening as it speaks of our experiences becoming locked into our flesh and the kindnesses we show will be received and will lead to our recovery... Another valuable lesson learned. I am not cloned but have a unique makeup that interacts with my intellect. I need to use it wisely and be ok with being the odd man out even if 90/100 people can successfully follow an established protocol. Thanks again Justin for opening this up. There's not enough honest communication in both directions on IF. We in the alternative medicine community do not need to be closed upon ourselves the way we report some in Allopathic communities can be about us. Blessings always..

Dr Justin Gallant ND

4/25/2018 04:55:08 pm

Hey Lorraine,

Thanks for sharing your experience!
I'm glad you found a routine that works well for you.
It's definitely important to listen to our bodies and be critical when things don't feel right.
Good luck on your health journey!

Debra Bradt

4/28/2018 12:42:34 pm

I've been trying to figure out what's making me feel so bad and maybe this 16-8 fasting/eating plan is doing it. I've been on it for about a month but for the past week, I've been feeling so rotten. I had been a real couch potato with super work stress for a long time, but I finally quit my job, got a trainer and started to walk and work out. I already played tennis, but I increased the number of days per week I was playing. I was losing some weight and walking 3 miles a day with no days off and I thought it was all going great. Then last week it started with feeling so tired and sleepless nights and heartburn when I hadn't eaten anything for hours before bed, and anxiety attacks at night, digestive issues, feeling almost faint at times. My blood pressure was rising a bit and it's been a week of hardly being able to get out of my own way. I just want to lay on the couch. I'm stopping the 16-8 today to see what happens this week. My family has always teased that you don't want to deal with me if my blood sugar is low, but it's not been an issue for years, since I was overeating for a long time. Maybe it's low blood sugar and this 16 hour fast each day that's making me feel so bad. Thanks for your article.

Dr Justin Gallant ND

4/30/2018 12:29:41 am

Hey Debra,

Thanks for writing in!
Hopefully you can find something that works well for you.
There are several other options like paleo, low carb, low carb high fat, low carb high protein, ketogenic diet, etc... where you can eat regularly and not stress your system so much.
Good luck on your health journey!

Carmela Gueli

5/15/2018 05:46:51 pm

I'm one to do my homework before starting anything. I came across IF as I was desperate to lose weight as diabetes and high blood pressure runs in my family. I started IF October 19/17. I've lost 31lbs. At 52 losing 10lbs was impossible. I love the way I look now but I'm experiencing anxiety. I been feeling this way for months. Having to deal with stress when I'm always anxious is painful. I don't like my family/friends and coworkers to see me this way. After reading your article I will definitely stop doing IF. But kind of diet do you recommend and how long will it take for me to feel better.
Thx Carmela

Dr Justin Gallant ND

5/19/2018 10:32:07 am

Hey Carmela,

Sorry to hear how you've been feeling.
I can't recommend anything specifically to non-patients.
If you let me know where you're from I can try to find someone who can help one-on-one.

Carol

5/21/2018 12:48:07 pm

I just started this 5 days ago and am having a problem with insomnia and feeling hyper. I'm wondering if I had a small can of V8 before bedtime (30 calories) it might prevent this, although it might be breaking my fast. I like NOT being able to eat for a time period though...it's the easiest way for me to minimize my calories and I really never feel hungry....just hyper!

Mercedes

5/23/2018 12:10:34 pm

I have started IF for the past 10 days and lost the craving for food. Any intake of larger amount of feed will cause nausea. Bloated stomach and worse I started throwing up after a normal meal for the past two days. I am stopping IF and not taking any risks to my health of turning to bulimia

Jaana

6/13/2018 02:07:55 am

Hi,
I have adrenal issues and noticed that if night fast becomed more than 12 hours (maybe 14 ), I started develope same symptoms that i had when my adrenals were worst.
I did fast just during the nights and it just kinda fell in that 12 hours fast naturally. During the Day i try eat regularly and very healthy.
My question is : can even this night fast of 12 hours have effect on adrenals badly, do i need just wake up earlier for breakfast or can i continue this routine max 12 hours night fast and eating every 3-4 hours during the Day?

Dr Justin Gallant ND

6/13/2018 10:46:48 am

Hey Jaana,

You should check out my other article on how our blood sugar and cortisol is affected at night. https://www.drjustingallantnd.com/blog/why-do-i-wake-up-between-1am-and-3am

I can't provide advice to non-patients online, so I would see if there is anyone in your area knowledgeable in this stuff so you can work with them and figure out what is best for you.
Sometimes tracking your nutrition, sleep and symptoms can help determine what is best and what's not working for you as well.

Joanna

6/18/2018 03:12:09 pm

I really liked your article. I kept hearing and reading everywhere how good fasting is for you so I decided to try it. I tried 16/8. At first I thought it was going well, but after a few weeks I started having heart palpitations in the evenings and mornings. They would get better after I've eaten something, but when I was fasting they would be there almost non-stop. I was also feeling anxious for no reason and it was very difficult to relax for me. And I couldn't find anything that would explain it, other than low blood sugar, I guess. It was like 2 years ago, and now I found this article and it all makes a lot more sense. Thank you.

Shortly after dropping the fasting I got the first flu (I was 27) in my life. I usually get a mild cold once a year or so, so that was quite new to me. I don't know if this was just a coincidence, or maybe fasting did mess with my immune system...

Dr Justin Gallant ND

7/16/2018 01:39:31 pm

Hey Joanna,

Thanks for writing in!

Your experience is important for others to read.

Jillian

7/25/2018 11:26:49 pm

I have PCOS and have been trying to loose weight. I have done Atkins induction phase for about two months two years ago and with a switch of birth control I had terrible Deb imitating anxiety. I obviously stopped birth control and the diet. Took me two years to “level out” with minor anxiety. More of a phobia of being stuck in traffic as my first attack two years ago was in the vehicle while driving through a storm on the expressway. Anywho, fast forward to now. I still have cysts on my ovaries and weight to loose. Started IF about two weeks ago. Had a little bit of an issue yesterday stuck in a.m. traffic again and felt as if everything around me was spinning. Btw this was during my feeding window. I am doing 16/8 daily. Today also was a little on high end and took some of my CBD to help. I’m desperate to loose the weight and help my PCOS but this anxiety! Not sure if it’s directly related as both times I was highly anxious was during my feeding window. Right in the middle of it honestly. It’s so depressing! I’m losing weight but also losing my marbles again.

Edward

8/20/2018 03:40:05 pm

Google Scholar says the opposite of what you are saying. Here is an example: https://www.sciencedirect.com/science/article/pii/S095528630400261X

Dr. Justin Gallant ND

8/20/2018 10:05:43 pm

There are several comments above of personal stories of how IF has affected real-life human beings. Those should hold more weight than rodent and monkey studies that have many, many confounding variables.
I’m seeing clinically that doing IF while in ketosis yields much less negative results but those who have higher carbs and do IF have the worst effects.

Kim Treftlin

8/24/2018 03:33:40 pm

Great info! Wish I would have consulted you before doing intermittent fasting.. after a few months I developed hypoglycemia like I haven't had for decades! You're the best!!

Dr Justin Gallant ND

8/28/2018 04:55:26 pm

Thanks Kim!

9/11/2018 12:54:47 pm

Hello everyone,
Tried lowering carbs, sugar and alcohol but not on Keto. I do exercise 3-4 times a week. I have been gaining weight for the past 2 years (3 kgs) going around my belly. Now I am adding some IF to my healthy habits. Trying to go 16/8. I am adding coconut oil to my coffee to help me last the 16 hours. However, I am getting palpitations and anxiety. My period started having some irregularities. Is it the IF? The coconut oil? Am I entering pre-menopause? All of the above?

Dr Justin Gallant ND

9/18/2018 04:31:22 pm

Hey MO,

Thanks for writing in!
I'd see your local naturopathic doctor if you're in a regulated region, so you can get some answers. It's difficult for anyone to know who doesn't do a proper health history.

Stephanie

9/15/2018 08:37:57 am

I was doing a 14/10 cycle for several weeks and then switched to a 16/8 cycle for the last several weeks. I have been experiencing heart palpitations rather frequently lately and just decided to Google this today with my intermittent fasting to see if it was common. I’m not really doing it for calorie restriction as I have a specific set of macros that I’m following and I get all of my protein (120) fats (60) and carbs (135) in during my feasting period. I am guessing this doesn’t really matter since I am still experiencing palpitations?

Dr Justin Gallant ND

9/18/2018 04:32:49 pm

Hey Stephanie,

Thanks for writing in!

In my practice, it seems like those who are fasting but still having a fair amount of carbs will experience cortisol spiking symptoms like palpitations, anxiety, insomnia, etc..., while those who are fat-adapted (keto) are much less likely to experience them during their fasts.

Brent

3/30/2019 09:14:32 pm

The following study shows Cortisol decreases during fasting from 8 hours to 24 hours. Can you please comment?

https://academic.oup.com/jcem/article/90/2/741/2836628

Alisia Young link

12/25/2019 06:49:34 pm

Thank you Dr. Gallant for posting this! As part of doing patient research, intermittent fasting kept coming up to address blood sugar regulation and weight loss. Your article has given me a new angle to consider in my treatment plan and I'm glad to have seen this before going forward with it!

Brent

2/29/2020 11:40:31 am

I am posting again to say that Dr. Gallant is exactly right about this.

I did OMAD for 4 days straight drinking only water and black coffee on an empty stomach for 23 hours a day.

I put my self into 24/7 fight or flight panic and anxiety. The caffeine on an empty stomach combined with counter regulatory hormones epinephrine and adrenaline put me into a mania.

My blood pressure went to 186 over 113 at the doctors office and he wanted to put me on a drug so heavy only mental patients get it.

The only relief I get is taking a walk in direct sunlight. I hope and pray this goes away soon but heed my warning, you can seriously mess up your brain, hormones and life doing IF.

6/22/2020 02:02:15 pm

No one mentioned that Intermittent fasting causes a huge decline or zero libido in men. It's best to eat low calorie (no-complex carb) for Breakfast, Lunch and med-large dinner.

Melissa

10/14/2020 10:43:34 am

For me going keto and starting IF (5 hour window) produce the same symptoms of insomnia adrenaline ect. Both diets do it to me but then after a few weeks I feel better in both in those ways. I know it has something to do with carbs. Overall IF has made my skin amazing, taken away constant hunger I get when eating breakfast ( I always eat low carb breakfast) weight loss, tons of energy and mental focus. My mental health depression has improved as well. I still follow low carb, but not keto with IF. I find when I go to low carb under 50g on any diet my depression gets BAD. I am 40F, 125lbs FYI

Zena

11/22/2020 08:40:08 am

This!!!!!!! I have been doing IF for about 1.5years now. Initially I lost 15lbs but now i have gained more than that. All that is going through my mind is what am I doing wrong, I eat healthy, keep my calories in check, work out and am very active....the scale shouldn'tbe going up, I have also been stressed out this year with other things. I am going to cut out IF and see if it makes a difference.

Lena

3/8/2021 05:38:11 pm

I did IF about a year ago to lose weight. I did OMAD and then a short eating window. I found it surprizingly easy to do and didn't suffer from much hunger. I went from 199lbs. to 160 and felt very well the entire time. My high blood pressure and high cholesterol disappeared, and my skin got much better, as did my hearing! The ear wax no longer appeared. My blood sugar was ok. I was 160lbs. for many decades, then crept up last 20 years, I am now 61.

Now, I was able to get back to 189 with poor diet and NO exercise. At least I have a pandemic to blame! So a week and a half ago I started OMAD again to try to get back on track. My diet has been mostly clean. One thing it does accomplish is breaking the sugar addiction effectively. After several days, and scheduling difficulties I went to 4 hour eating window. After 20 hour fast each time I eat I get all the symptoms of panic and I also go nearly comatose. I get very irritable, tight chest, racing heart, short of breath, somewhat nauseous. Also the fatigue wave cannot be overcome, I can just about guarantee if the house caught fire I would not be able to gain enough consciousness to escape the house. So, I feel miserable for several hours each day after eating, and the rest of the time I feel quite well. It is no longer worth it to me, I need to exit this strategy. I believe if I eat cleanly three meals a day I should be okay. My downfall has been tea and cookies all night long. I have no idea why it was a great success a year ago and now makes me feel miserable. I'm also borderline diabetic now 5.7 A1c for last 6-8 months best I can remember, another reason I attempted IF.
Many Thanks Dr. Gallant, I will try to profit from your knowledge and wisdom and try to summons the almighty discipline!

Angie

12/15/2021 02:53:35 pm

I too have had a bad experience with IF. I initially, like others really liked this eating routine, lost some weight, was not particularly hungry and was initially energized. However, I began to notice a consistent rise in fasting blood sugar, even after 16 hrs. When I began, my blood sugars were normal (80-85). But, after a year of 16/8 and 18/6, my fasting sugars have risen to 100+ and I experienced increasing insomnia, higher thyroid supplementation, and low morning temperatures. I reluctantly abandoned IF and am now eating 3 balanced meals with 1-2 Adrenal cocktails but blood sugar remains elevated. As a side, post prandial blood sugars are within normal range. Strange that I can have blood sugar=91 when I go to bed and fasting AM sugar will be 100+. Very frustrated and disappointed that I allowed myself to ignore what I “know” as a health coach, the affects of stress on cortisol/blood sugar, and assumed I would some how be spared.

Kate

10/31/2023 08:41:17 am

Hi Dr Justin, just surfed in looking for answers. I have been intermittent fasting for decades. It has worked for me all these years. Have also tried calorie counting (not that effective at all), and then Atkins diet (very effective and extremely pleasurable as I love fat and protein!). The most effective by far was intermittent fasting, one to one and a half hours of gym training whilst fasting, and reduced calories - this method helped me drop three dress sizes in two months. It wasn’t a long term solution, but it turned out to be a permanent one. However, I was in tip top condition physically, despite having been binge-drinking and a heavy smoker. I had no health issues nor medical conditions, and wasn’t on any medication. This method has also kept the weight off for ten years. Since perimenopause, though, I’ve found several issues with intermittent fasting - the first was a severely low ferritin level, and the second was heavy periods, palpitations, lack of energy, shortness of breath (all connected, and all especially heavy periods disappeared after iron supplementation). At menopause, I experienced extremely bad anxiety, bowel distress, depression, giddiness, shortness of breath, palpitations, insomnia - some of these went away after iron and B12 supplementation. The thing about IF is that is depletes the body of nutrients. I found that a minimum of 100 mcg of B12 per day sorted me out, and I was a brand new person. I live in Europe and there is also a pack of 500 mcg which I’m thinking of trying. Today, I had sudden diarrhoea again whilst fasting - it has happened before, and always past the 18 hours mark. It’s never happened before, so I’m looking for answers as to why, or what I can do to avoid it. I got the time wrong as we are now in daylight savings and I looked at the wrong clock. I ended up not bothering to eat as I didn’t feel hungry, and thought I was still at the 17 hour mark… then I went out and lost track of time, and came home. Suddenly I felt anxiety after feeling giddy, and needed to go to the toilet after a few glasses of water. Flush! I’m wondering if anyone has experienced this, or whether Dr Justin you have any knowledge or advice on this. Could this be the depletion of nutrients that causes the anxiety and the purge…?

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