Fast Shot: Shorter and Longer Fasts—Does It Matter?

In this fast shot, Donna Reish, blogger, author of 100 curriculum books, Intermittent Fasting teacher, and seeker of health, teaches the benefits and downfalls of fasting for shorter periods times vs longer periods of times each day. She begins with understanding the four ways we lose inches and fat with fasting and then discusses other health benefits that can be affected by fast length. She then describes the process of shorter fasting, that is 16-18 hour fasting hours. She discussed how this allows for two meals or more, how some people have self control problems with that long of an eating window/that many eating opportunites, how effective this approach is for clean/whole foods eaters, the this fasting length’s potential effect on Appetite Control. Then Donna discussed the longer fasting times,, such as 19 to 23 hours, including the potential benefit of one meal a day, the length of time it may take to burn through stored glycogen, and how the body gets used to longer fasts/trains grehlin. She brings it all together in summary between the two time conundrums.

A. First Understand the Mechanisms of Fasting and Weight Loss/Inch Loss With Fasting

  • 1. Four ways we lose inches and fat with fasting
    • a. No insulin/no food=fat burning—putting body in best position to burn its stored energy for fuel
    • b. Balancing hormones—grehlin, leptin, Human Growth Hormone, etc., for most appetite control possible
    • c. Reducing caloric intake over time resulting in long term weight loss
    • d. Body recompositioning as the body burns its own body fat—inch loss often happens before fat loss.

  • 2. Other benefits of fasting outside of weight loss and inch loss and appetite correction, etc., happen with shorter and longer eating periods
    • a. Research showing that even 12 hours fasted is helping to reduce breast cancer
    • b. Research showing it takes 18 to 36 hours of completely clean fast to cause autophagy
    • c. These benefits come into play when making fasting length and “clean-ness”

B. Shorter fasts (16-18 hours)

  • 1. Usually allow for two meals or more
  • 2. Some people eat too much in that longer eating window without other eating protocols in place (calorie reduction)
  • 3. Depending on what you ate yesterday and the day before, it might not be long enough for body to go into fat burning mode (using body fat for fuel)
  • 4. Appetite might not be as controlled if you graze during the eating window or eat too many processed foods (real foods help with AC as does protein and fiber)

C. Longer fasts (19-24 hours)

  • 1. May result in truly one meal—this can cause a better caloric level (calorie reduction)
  • 2. Long fast gives lots of opportunity to burn through circulating glucose and stored glycogen so this will likely increase body fat burning (using stored body fat for fuel)
  • 3. Can work both ways for AC
    • a. Backfire—I did so great fasting, so I can eat as much as I want (not too likely with AC and not usually at all for real foods)
    • b. Body can get used to no food for that period of time and if you truly eat one snack and one meal without grazing or just one meal, AC will probably be superb

D. So Shorter or Longer Fasts?

  • 1. Base in part on goals (weight, size, health, brain, autophagy, etc)
  • 2. Base in large part on sustainability and adherence—what can you truly do without giving up?
  • 3. Base in part on what you eat—people with healthier diets and fewer processed foods can usually do 2MAD and lose or maintain; if you honestly want a restaurant style meal and dessert every day, longer fasts will be needed
  • 4. Base in part on your success so far and where you are in your weight loss journey
  • 5. Can alternate!

Fast Shot: Should You Exercise Fasted?

In this Fast Shot, Donna Reish, blogger, health seeker, Intermittent Fasting teacher, and author of over 100 curriculum books for students in preschool through grade twelve, teaches about exercising fasted. She begins by explaining the three main types of exercise and what each one does in terms of calorie burning vs toning, etc.—cardio, strength training, and HIIT. She then describes the three ways to get into ketosis—keto diet, fasting, and exercise ketosis. Then she tells when she likes to do strength training and rowing and why, including how working out during the fast gets you into fat burning sooner (and sometimes very quickly depending on the intensity of the workout and what you ate the night before). Finally, she gives some tips for adding exercise to your Intermittent Fasting routine.

A. Understanding exercise in a nutshell

1. Cardio—fat burning, sustainable for long period of time; 50-60% of heart rate; able to talk through it; doesn’t build muscle per se

2. Strength training—carb burning, long term benefits, look smaller regardless of weight; muscle is tighter and smaller than fat, so when you strength train, you build muscle—when you lose fat, that muscle looks leaner and thinner than the fat that was there

3. HIIT—only sustainable for 30 to 90 seconds at a time (or it isn’t true HIIT); carb burning; 85-90% of heart rate; can’t talk through it


B. Three types of ketosis in a nutshell

1. Keto diet

i. 75-80% fat; 10-15% protein; 5% carbs

ii. Puts you into “ketosis” where your body burns ketones/fats rather than carbs

iii. Some say this happens through caloric reduction; others say it happens due to a caloric “padding” you get through mostly eating fat—body gets used to burning fat

iv. Puts you into ketosis 4x faster than traditional diet

2. Fasting

i. Usually happens between 16-18 hours of non-caloric fasting (though some say it still happens if you eat fat, like cream)

ii. Happens for the same reason as keto diet—you’ve burned through glycogen stores and now use body fat and ketones instead

iii. Puts you into ketosis 20x faster than traditional diet

3. Exercise ketosis

i. Especially happens through strength training because you’re burning the glucose stored in your muscles

ii. HIIT also helps it

iii. Can make you feel like you’re starting fasting all over again!


C. When Should I Exercise?

1. My preference is around 12-16 hours fasted—not hungry at all and not full from eating either

2. Can do it anytime

3. Doing it fasted puts you into fat burning quicker because you’re burning through the last of the glycogen stores

4. Doing it fasted can make you feel like you are starting fasting all over again!



D. Tips

1. Don’t do strength or HIIT in first couple of weeks of fasting (you are doubling up on burning through glycogen and can be super hungry and tired—and you won’t know what is causing it!)

2. Be prepared to feel bad at first!

3. Drink mineral water and take minerals!

i. Magnesium

ii. Mineral water—flat or sparkling (I used two bottles each morning when I began working out hard)

iii. Pink Himalayan salt

4. Start out slowly as you will feel like you are back to starting fasting all over again!




“A Month to Learn It—a Lifetime to Live It”—

Fast Shot: When Water Makes You Nauseous During the Fast


In this Fast Shot episode, Donna Reish, blogger, author of 100 curriculum books for preschool through twelfth graders, seeker of health and fitness, and Intermittent Fasting teacher, talks about the benefits of water and what to do when you can’t stomach water during your fasting hours. She begins the broadcast with the many ways water benefits us during fasting, weight loss, and for health. She then describes the importance of measuring what you want to move–as in counting your water each day. Then Donna gives several potential solutions to the water-makes-me-nauseous-during-fasting issue, including various kinds of water, sparkling water, ice, hot water, lemon, and lime. Finally, she describes other out of the box ways to get water in, including coffee, tea, decaf coffee/tea, flavored waters, and tanking up during your eating window. She encourages listeners to implement Bert Herring’s “study of one” to determine anything that might spike insulin during the fast and the importance of avoiding those things.

read more…

Two Coaching Options For 2019 From Donna Reish



In this video, Donna Reish, author of over a hundred curriculum books for kids, blogger, health seeker, and Intermittent Fasting teacher, explains her two coaching options currently available. The first one is her month-long Intermittent Fasting course ( in which Donna guides her students via daily videos, outlines, graphics, charts, and images in everything they need to get started on IF! This comes with a private course FB group in which Donna interacts with students daily and answers questions as they come up. This course is truly “a month to learn it; a lifetime to live it!” Secondly, Donna describes her health and weight management coaching for her and her team’s Plexus Ambassadors and customers. With a minimum monthly purchase of plant-based, health-changing Plexus supplements, users are invited to join her closed FB group called Reishes’ Serious Plexus Peeps where Donna will address tons of issues related to health, fitness, food, and weight management in live videos three times each week! Consider one or both options in which you will learn how to help your body help you achieve your goals!!!

read more…

Fast Shot: Why and How to Start IF During December!




1) You have special foods to look forward to during your eating window! This always makes starting easier.


2) You can be a fat burner by January 1st—get ahead of those New Year’s resolutions, and make IF a lifestyle!


3) Feel good during the holidays–instead of so much food heaviness, etc.


Fast Shot: What Should I Do When I Reach My Goal Weight?



I love questions from readers and viewers! They cause me to think deeply, research more, and examine things from different points of view. So send me questions! 🙂


Today’s Fast Shot video is about weight maintenance. Oh glorious day! I can’t wait…how about you?


So here are some thoughts I have as someone who is still 20 pounds from that exhilarating place! 🙂

read more…

Fast Shot: Ready to Face Holidays With an IF Lifestyle!


I wanted to give my FB group a little pep talk and help them make IF a lifestyle during the upcoming holidays, so I made a quick Fast Shot video for them that I thought you, my blog readers and YouTube viewers, might find helpful too.

Happy Thanksgiving! And blessings to you on your weight management and health goals this holiday season!

Preparing for Thanksgiving With IF

read more…

Intermittent Fasting Journal – Week 29


In this broadcast, Donna Reish, blogger, curriculum author of 100+ language arts/writing books, and Intermittent Fasting teacher, teaches listeners about four metrics that we can use to track our Intermittent Fasting journeys. She starts out teaching about scale weighing, including the fact that the scale weighs everything that is placed on it—water, fat, muscle, bones, stool in our intestines….everything. She explains how to best use the scale as an effective tool, including averaging your weights for the week to get a total for that week’s weight, weighing at the same time in the same clothes, and not using the scale as your only metric. Donna then moves on to the tape measure as a second assessment. We need to remember that the tape measure can measure fat loss AND muscle loss, and that the measuring tape can be extremely subjective. Thirdly, Donna teaches about body fat percentage, including a few ways to measure it, the benefits of using it as a metric, and determining body fat goals. Lastly, she teaches her personal favorite metric, the goal pant. Here she helps listeners see the visual motivator that goal pants can be and advises on choosing the right pants so you don’t get discouraged. Today’s broadcast is sponsored by Plexus Boost, a plant based capsule that boosts metabolism, helps with hunger, and aids in energy boosting. This product has amazing botanicals, including caralluma fimbriata (edible cactus the ward off hunger!), green tea extract, yerba mate, higenamine, chromium, and bio-available B vitamins.

read more…

Fast Shot: Adding Time to Your Fasting Window Strategically and Painlessly

In this Fast Shot episode, Donna Reish, blogger, author of 100+ curriculum books, and Intermittent Fasting teacher, explains to listeners how to go about adding a fasting hour (or hours) to your fasting window. She starts by giving some ideas for when someone might want to add fasting hour/hours, including preparing for a special occasion, when someone is plateaued for a while, working on getting rid of the last ten to twenty pounds, and more. She then recommends when someone might NOT want to add more fasting time. Donna then looks at a couple of ways to add an hour and advises people to choose their plan ahead of time–another hour daily, extending their daily average via an app, adding an hour on weekends, etc. Finally, she gives tips and tricks for making it through another hour of fasting, including how to trick ghrelin, how to avoid dehydration and mineral imbalances, and more.

read more…

Fast Shot: “I Can’t Seem to Get Beyond the Hangries of the First Few Weeks!”


Welcome to another Fast Shot Video post! I have loved creating these! They give me a chance to answer reader’s questions immediately in my private FB group–and I love the challenge of trying to stay under ten minutes! (Failed this time…but close at around twelve minutes!)

This is a super important question for people just starting out in IF (and one reason that I created the 20 page freebie, “IF Start Up Charts”! and my month-long course). The first few weeks can be challenging with hunger and the hangries!

read more…

Pin It on Pinterest

Share This
Share via