How Long Should You Fast?

A common question that I get all the time is, “If fasting is so wonderful, how long should I be doing it?”

To start with, the first question you want to ask yourself is, what benefit are you trying to achieve with fasting. I have identified that there are 7 different types of fasts, and they all have slightly different benefits to them.

If you are not familiar with the 7 different types of fast, please reference youtube video: for background on how to do all 7 of these fasts.

But in general, this is how I approach each one of these fasts:

Intermittent Fasting

This is your beginners fast. If you have never fasted before, you are going to want to start here and master intermittent fasting. With intermittent fasting, you will get a surge of growth hormone which will help slow the aging process and burn fast. You will also find yourself in a mild ketosis and initiate the beginning of autophagy. How long should you do intermittent fasting? I recommend that it is done daily and is apart of your daily lifestyle.

24 Hour Fast

This is often known as a dinner-to-dinner fast or one meal a day (OMAD) fast. The reason you would want to do this particular fast is to produce more ketones, have a deeper detox experience, and to keep insulin levels low for a longer period of time so that your body is forced to utilize energy from stored sugar. This fast is great for people who are weight loss resistant, want a deeper ketone or autophagy experience. I recommend people do this fast at least once a week.

24-36 Hour Fast

The purpose for these longer fasts is really to keep insulin down and go after stored sugar. If you are familiar with Dr. Fung and his book The Obesity Code, one of his key strategies for releasing long-standing weight is fasting for longer periods. If you are extremely weight loss resistant then you are going to want to implement the 36 hour fast on a weekly basis. Many of you will notice with this fast the beginning of stem cells being released. Stem cells are repair cells, so often I will have patients of mine do a 36 hour fast to heal a musculoskeletal injury.


Fast mimicking is a style of fasting made famous by Valter Longo. He researched that limited calories, low protein also force the body to release stem cells. I recommend fast mimicking to patients who want the benefits of a longer, block fast, but still want to be able to eat food. Fast mimicking can also be a great fast to train your body for longer fasts and a great way to break a block fast.

Autophagy Fasting

Autophagy fasting is proving to be great for weight loss and detoxing as well. The reason to do autophagy fasting is because you get maximum weight loss benefits, while still being able to eat a fairly regular diet. For many of my patients, autophagy fasting has become a part of their weekly diet variation. A couple of key pieces of autophagy fasting is keeping your protein under 20 grams and breaking your fast with fat. See my autophagy fasting playlist on YouTube for more details.

Dry Fasting

The research on dry fasting shows us that it can decrease inflammation and increase BDNF. BDNF is fertilizer for your brain. Incorporating dry fasting in to your weekly diet variation, for those of you that want better brain clarity, improved memory, and better mobility, this would be the one you would do. It is not recommended that you dry fast for more than 24 hours.

Block Fast

A block fast is for those of you that want MASSIVE cellular repair. Some experts believe that you would kill every cancer cell in your body if you did a 3-5 day block fast multiple times a year. We use block fasting in our clinic for more severe conditions, for people who want to maximize their stem cell production or need a full reboot of their immune system.

Look at each one of these fasts as a tool that you can use at different times. The way that I apply fasting to my life :

  • Intermittent fast daily,
  • (1) 24 hour fast a week
  • one time a month I take a 5 day period and practice one of the other fasts. Lately, it’s been autophagy fasting or fast mimicking.

If you want more information on fasting, join me in my Resetter Tribe on Facebook, as we fast together as a community one time a month.

How to Cycle Your Fasts & How Long Should You Fast

2020-07-29T14:08:01+00:00Fasting Techniques, Health|


  1. Sofia June 16, 2020 at 8:22 pm - Reply

    I fasting for everyone. I have been doing 16 hours fasting frequently, but last week I did 40 hours and since then my body has not adjusted. After the fast I had two days of diarrhea, and have not been sleeping great, my period lasted 1 and a half days and the last two days I have been having a headache.

    • Cath October 10, 2020 at 4:54 am - Reply

      I’d bd curious what Dr Mindy answers . I’ve found that only know I’m out of adrenal fatigue and my hypoglycaemia not present I can do IF and slowly extending it an hour or 2 but i wouidnt of dont it before . My periods are really light & short anyway so I’m thinking much longer wouid be good to avoid . Oh and at set times of the menstrual cycle .. day 12-14 And I can’t remember the other days she said

    • Avid Faster August 16, 2022 at 7:26 pm - Reply

      The diarrhea happens to me on extended
      /prolonged fasts; my longest being 76 hours. It is probably due to the migrating motor complex in your gut. It’s the body’s way to clean up your intestinal tract. Just make sure you’re drinking at least 80-100oz of water each day, especially so if you are exercising and/or experiencing diarrhea. If you have headaches, take some electrolyte supplements (potassium, magnesium and sodium). I’ve found the potassium is best taken as the No Salt brand seasoning because the pill supplements are extremely minimal in the amount of potassium for each pill (for good reason as most don’t need large quantities of potassium since most eat regularly). My cycle gets kinda wonky (shorter duration – but I’m personally not complaining about that aspect lol) when I do longer fasts as well. Probably just an adaptive measure but if you’re trying to conceive or worried about your hormones, just get a quick blood work from your doctor. Disclaimer: I’m not a medical professional though so talk to you doctor beforehand, especially if you’ve got medical conditions (heart problems, diabetes, high blood pressure, etc.).

      • Ashley January 17, 2024 at 10:54 pm - Reply

        Hi, I just did 60hour fasting. It was my first time in 4 years. I attempted to do 72 hours, but I got really dizzy and my legs were shaking when I got up. I wonder why it happened. I drank water with sea salt. Glucose Level was only 72. Was it a good call to stop fasting when I have symptoms like that?

    • Avid Faster August 16, 2022 at 7:31 pm - Reply

      The sleeping problem isn’t uncommon. Fasting, especially longer ones, does have a stress effect on the body (albeit with great benefits that follow it) and you do produce increased amounts of neurotransmitters (also hormones) such as epinephrine and norepinephrine which causes heightened alertness and perhaps even restlessness. Once you become more acclimated to this, it won’t be so disturbing. Disclaimer: I’m not a medical professional though so check with your doctor beforehand.

  2. Rosemary collins August 15, 2020 at 12:26 am - Reply

    Just discovered you…. Wow thank you
    Interested in everything you have mentioned.
    Underactive thyroid, weight issues all myy life and wanting to cure bursitis of the hips.
    And I know fasting will do this.

  3. Rosemary collins August 15, 2020 at 12:26 am - Reply

    Just discovered you…. Wow thank you
    Interested in everything you have mentioned.
    Underactive thyroid, weight issues all my life and wanting to cure bursitis of the hips.
    And I know fasting will do this.

    • Cecilia Grobbelaar October 5, 2021 at 8:22 am - Reply

      Hi very interested in womens reset, fb group and chart… my body in hormonal havoc…please

  4. Frank August 21, 2020 at 4:48 pm - Reply

    Resetter group
    Reverse a metabolic

  5. Ellaine Iraola October 23, 2020 at 12:32 pm - Reply

    How to do the block fast? Is it just water for 3-5days?

  6. claudia Hollander October 27, 2020 at 6:53 pm - Reply

    I’m thinking of joining your resetter’s coming up soon. How can I get more information about joining.

  7. Dawne Duckworth March 14, 2021 at 4:55 pm - Reply

    I have been doing intermittent fasting 16:8 to 18:6 for 2 years. OMAD as well. I am at a stand still- loss 40 pounds but need to lose at least another . My biggest question is when you say a fasting day should you do this every other day? Also on fasting day I can’t get 1000 calories as have to keep fat down now as well so low carb low fat. Should calories been taken into account due to starvation mode. I am 68 and am doing a lot of physio to correct my stance. Gradually increasing walking but hard to get 6000 steps on fit bit. So main question is calories?

    • Sunshine March 6, 2022 at 3:23 pm - Reply

      You say you are doing both low-fat and low-carb. The only other category of food is protein. Are you eating high protein? That could lead to kidney problems. High-fat, Moderate-protein, and Low-carb are a ketogenic diet.

    • HL March 17, 2024 at 10:01 pm - Reply

      You are not alone! And! You are doing better than I! I gained my 30lbs BACK after IMF for 4 years….and KETO for 2 previous to last year.

    • HL April 23, 2024 at 6:45 pm - Reply


  8. Christy Castronovo April 5, 2021 at 10:41 pm - Reply

    when is the next resetter group?

  9. Greta Benson August 9, 2023 at 3:50 pm - Reply

    Resetter group, please! Hashimotos, metabolic syndrome and chronic fractures.

  10. Dawn August 28, 2023 at 11:48 pm - Reply

    Fasting benefits chart and reser

  11. Sara October 30, 2023 at 1:46 pm - Reply

    Resetter please

  12. Lisa December 18, 2023 at 9:13 pm - Reply

    I am a type 1 diabetic; I had a hysterectomy at age 35 and this past summer I did a Dutch test and found my hormones have tanked – what type of fast can I do?

  13. Bodil Johansen December 30, 2023 at 8:35 am - Reply

    Thankyou so so much for your work and the way you show up with optimism and a smile. Love from Denmark.

  14. Dee May 3, 2024 at 3:33 pm - Reply

    Dr Mindy with your tools and knowledge I feel like I’m saving my own life, and I cannot thank YOU enough for sharing this valuable information with women…
    As I’m not on any social media I haven’t joined the communities, but I have a specific question that I can’t find an answer to online.
    I have a 21 day cycle and I feel like I’m missing the Hormone feasting days to promote progesterone leading up to my shed.
    I go from fasting days days 17-20 and then I don’t fast on shed day and then I go right back to fasting days 1-10.
    How do I back this up to ensure I’m fasting and feasting on the right days of the month with a 21 day cycle?
    Thanks so much!!!!

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