Weight Management

The Truth About Intermittent Fasting

June 19, 2017

The Truth About Intermittent Fasting

WHAT IS IT Intermittent fasting (IF) is an eating pattern that has technically been around for thousands of years.  This was the natural eating pattern for early humans.  At times, large amounts of foods would be available to us, and during others food sources would be scarce. This leads to a pattern of feasting and fasting which our bodies adjusted to.

Fast forward to present day,  the practice of IF centers around purposefully restricting food intake to a certain period of time (fed state) and fasting for a certain period of time (fasting state).  There are several options and patterns one could follow depending on your schedule and lifestyle:

Pattern Fed State Fasting State
Daily IF (Leangains Method) Any 8 hour block of the day Any 16 hour block of the day
Weekly IF 6 full days of the week 1 full day of the week
Alternate Day IF 4 full days of the week 3 full days of the week

PROPOSED BENEFITS Proponents of intermittent fasting claim that the practice can help protect memory, slow the disease process and encourage weight loss. Those who practice also tout a simplified eating schedule that can require less time and money. There is also a theory that during the fasting state the body’s cells are in a slight state of beneficial stress, which allows the cells to learn/adapt new ways of dealing with stress, providing a protective effect against things like disease and aging and increasing our body’s ability to build lean mass.

RESEARCH National Institutes of Health (NIH) references many studies which included both intermittent fasting and calorie restriction.  Studies testing these practices showed that in overweight women, intermittent fasting was just as effective as continuous calorie restriction on weight and insulin sensitivity.

Another study listed by the NIH done using overweight adults with asthma showed an improvement in markers of oxidative stress and other quality of life indicators. Other studies have been performed on animals.  A study included mice who fasted twice weekly for 24 hours demonstrated that mice overate on non-fasting days and did not lose weight.

EXPERIENCE We wanted to see what all the hype was about, so we decided to try IF for ourselves.  We chose the Daily IF pattern as this seems to be the most common and praised.  During “fasting” times we would drink plain coffee, tea or water.

ELLEN’S EXPERIENCE Initially, I had a headache in the mornings, as I set my eating time from 12 p.m. – 8  p.m.  The hardest thing for me was feeling “restricted”, that I wasn’t allowed to eat, even though my stomach was telling me I was hungry.  This continued every day, but did improve by the end of the experiment.

I also noticed when it was eating time, I overate.  I was so hungry and food focused, I ate quickly without allowing myself to enjoy the food or stopping to see how hungry I still was.  I found myself eating a snack at 7:50 p.m. just because I knew I couldn’t eat again until lunch time the next day.  Finally, I felt like it was hard for me to get in all my nutritional needs.  I was under on my fruit and vegetable intake, just for lack of time to consume them.  If done properly, this may be a realistic eating pattern for some individuals.  My main concern would be meeting a person’s energy needs as well as possible effects when taking medications like insulin or sulfonylureas.

CHELSEA’S EXPERIENCE:  It was tough for the first few days, but it didn’t take long to get used to.  My fed state block was from 11 a.m. to 7 p.m., which basically meant I was skipping breakfast and stopped eating after dinner.  I was VERY hungry to start the day off, but I could tell my body got used to the pattern pretty quickly.

After the first few days, I did feel like I had more energy through the day and less of an appetite.  However, because I knew I would be restricted later on, I ate larger meals during my fed state which were generally less healthy than they would be through my normal eating pattern.  I was just too excited about eating!

I did find it easy to plan meals during the work week, and it was easier to get to work because I didn’t sit down for breakfast.  However, my husband and I live downtown Omaha, NE and love to meet friends for dinner and drinks over the weekend, almost always after 7 p.m.  So, socially this was a very difficult eating pattern for me.

Both of us measured our body fat % vs. lean mass, tested blood sugar, and weighed ourselves prior to our experimental IF.  Chelsea experienced no change in fat, muscle, weight or blood sugar after her 2 week period of IF.  Ellen had minimal fat % decrease and no changes in blood sugar.

If you want to try IF for yourself, understand that planning is key!  Take measurements before and after so you can determine if this is truly beneficial for you.  We recommend journaling as well, noting your hunger and energy levels through your experience.   If you are on any medications that are heavily affected by food intake and/or weight (medications for diabetes, high blood pressure, and others) please consult your primary care doctor before starting.

  1. Ingrid

    I have been fasting for seventeen days as part of a religious fast. I have seen some health benefits as part of this fast. I have lost fifteen pounds. My fingers used to be swollen and have arthritic pain every morning. That has gone away. During the fast I drank a lot of water, I have been constantly thirsty and have experienced bad breath. I have had a protein shake at least several times for the second and third week of the fast. I am breaking the fast after twenty days and plan on eating a ketogenic diet.

  2. Terry

    Here is some recent research that is significant in regards to fasting, both for the immune system and possibly neurologic benefits. https://news.usc.edu/63669/fasting-triggers-stem-cell-regeneration-of-damaged-old-immune-system/ https://youtu.be/4UkZAwKoCP8 Don't eat anything white would help your weight and diabetes as well...but check with your doctor.

  3. Sherea Lee

    This is great! I was just thinking about doing this last week. After getting all of this feed back, I will definitely be starting this tomorrow.

  4. CHI Health

    Rose- Feel free to click the 'unsubscribe' link at the bottom of the email.

  5. Che

    Anderson- Like we mentioned in the article, the research shows mixed results on whether it's beneficial in one way or another. However, if you try it and you see results and feel better, it could be beneficial for you individually! I had very steady energy levels throughout the day while practicing this. However, in the end it just didn't work with my lifestyle overall. So, it wasn't for me. Doesn't mean it couldn't be good for you!

  6. Chelsea Gauer

    Cindy- If you have diabetes but would like to try IF, I would highly recommend working with your PCP, endocrinologist or diabetes educator during the first few weeks. You will likely be adjusting your medications quite frequently during this time, and could be ask risk for low blood sugars.

  7. Chelsea Gauer

    Steven- That is great that a ketogenic diet is working so well for you! In my years as a practicing dietitian, I’ve come to realize that not one diet works for everyone. The human metabolism sometimes feel like an impossibly complicated network, and everyone’s is so unique I don’t know that we’ll ever be able to define the “best diet.” Unfortunately, there is a lot of trial and error involved in finding a diet that both gives you results, makes you feel better, AND fits your lifestyle. I’m glad you found one that works so well for you. Some people just do better on a higher carb, low fat diet. You can find research to support both diets. As mentioned in the article, the research is still out on whether or not IF is overall beneficial. However, I think there is enough out there (in terms of research and personal testimony) to give it some validation, and could be worth a shot for many people. Right now, all we can say is try and see, if you are getting results and feel better overall, than IF might just be your new way of life!

  8. Helen Lange

    If losing weight is the goal, the best time to start fasting is at 3:00 in the afternoon. Start at 7:00 a.m. and eat a large, well-balanced breakfast, then a reasonable lunch sometime during the 8 hour day and a healthy snack just before 3:00. I've lost 20 lbs on this schedule, over the course of 6 months.

  9. Rose Flynn

    Although I definitely want to retain CHI emails from my Dr and any that pertain exclusively to me, I would prefer to opt out of newsletters and blogs if that is possible. I appreciate your help in this endeavor. Thank you.

  10. Sherry

    This is basically how I eat every day anyway. My husband and I get up and go to the gym every morning, so I don't make my "breakfast" until close to noon most days anyway, and we don't eat anything after dinner, so most of my food intake is within a 9ish - hour window.

  11. Steven Aschoff

    We are all so different. My experience with intermittent fasting has been fantastic! It took a few weeks, but I also switched to a ketogenic lifestyle - aka. Very low carb which I think helped. I lost 37 lbs in 6 weeks, my energy levels are through the roof. I even did full 36-48 hour fasts every other week. I never bonked on energy during my workouts (this is attributable to keto, not fasting) and my digestive function is awesome. It is a drastic change from what we are used to (programmed to believe is correct) that getting past the mental side of making such a dramatic change to something as fundamental to our lifestyle as eating can be daunting. I am still keto going on 4 months now. I See absolutely no reason to go back. Still also doing intermittent fasting for way more reasons than are mentioned to be of benefit in this article. On going keto, the belief that carbohydrates are essential is very misleading. There are carb based foods that may have essential nutrients, but they are not the sole resource for obtaining those nutrients. So basically saying any carbohydrate is essential, well, is absolutely false. The glucose your brain needs can be produced by your body as long as you are eating healthy fats and the proper amount of protein. This happens through a process called gluconeogenesis. One other thing I will mention about keto - my inflammation is way down and I no longer experience any of my arthritic pain. Granted I do not have a whole lot to start with, but I also believe I am not creating any new issues since I have changed my nutritional make up. I Highly recommend intermittent fasting along with keto!



  13. Anderson

    So, you still don't have any idea if this is beneficial or not?

  14. Michele Magner

    This is fascinating! Thank you!

  15. Michael

    My wife and I have been IF for about 2 months. I have gone from 218 pounds to 189 and am continuing to lose weight. My wife has seen similar weight loss as well. I have dropped pant sizes from a loose 38 to a comfortable 34. My IF routine is eating a protein rich diet consisting of breakfast around 8 a.m. and lunch, minimal carbs, and straight protein early in the evening. Nothing past that last piece of protein (chicken, steak, hamburger patty, etc) until the next breakfast. Have not felt hungry and do not binge eat. After the first 2 weeks most all of the cravings have gone away and I feel more in control of my intake and energy does not seem to be a problem.

  16. Aurang zeb

    I did fasting all month .I stop eating 4 a.m. - 9 p.m. I did 29 days. I lose almost 10lbs .I am Muslim .we do fasting every years one month .our fasting you can't eat or drink during the day .prophet Muhammad say do fasting every Monday. Once week !!!

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