6 Benefits of Intermittent Fasting (And How To Do It)

Heather Dessinger

This post contains affiliate links.
Click here to read my affiliate policy.
intermittent fasting

I’ve never completed a diet “cleanse.” When everyone else is giving up coffee, I’m blending mine with butter. Last year, if you’d asked me who was least likely to write about the benefits of intermittent fasting, I would have told you it was me.

And yet here we are, because intermittent fasting helped me increase my energy levels and lose my excess baby weight without changing what I ate . . . only when. And the more I’ve researched it, the more benefits I’ve discovered.

So what is intermittent fasting, and why is it so awesome? ^

Intermittent fasting (IF) is not a diet, it’s a lifestyle in which you limit food intake to a certain time window during the day. For example, I eat all my meals within a 12 hour window between 8am and 8pm, and I fast through the evening and while I’m sleeping. (This was really hard for me at first, because I was a huge late-night snacker, but it got easier very quickly.)

There are a lot of patterns of intermittent fasting, such as:

  • Eating all meals within a 12 hour window (say, from 8am – 8pm), then fasting for 12 hours
  • Eating all meals within a 10 hour window (usually 9am – 7pm), then fasting for 14 hours
  • Eating all meals within an 8 hour window (usually 10am-6pm), then fasting for 16 hours (You’ll often see this referred to as 16:8 intermittent fasting)
  • Every other day fasting (eating nothing one day, then eating normally the next)
  • Extended fasting

Although there may be certain situations when longer fasts might be appropriate, more is not usually better when it comes to intermittent fasting. Extended fasts can disrupt hormone balance – especially in women – which can lead to poor sleep, fatigue, fertility issues, depression, and other problems. (source 1, source 2)

On the flipside, a daily fasting cycle works to balance the ebb and flow of leptin (the fat burning hormone), insulin (the fat storage hormone), and other hormones that we make throughout the day. According to Dr. Lori Rose, who is my co-author for this post, that’s because our digestive tract contains a “peripheral body clock” that syncs up with our 24-hour circadian rhythm, and periods of daily feasting/fasting help “set” the clock in the same way that light and dark does.

Intermittent fasting helped me increase my energy levels and lose some stubborn post-baby weight without changing what I ate . . . only when. It was also a lot easier than I thought, which is good because I don't do diets.

Benefits of Intermittent Fasting ^

Before we jump in, please keep in mind that this article is for informational purposes only and is based on the opinions of the authors. It is not medical advice and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. As always, please use common sense and speak with your healthcare provider if you have a medical condition that might contraindicate intermittent fasting or any other lifestyle change. Please see my full disclaimer here.

With that in mind, here are some of the top benefits of intermittent fasting.

#1: Weight Loss/Healthy Metabolism ^

Remember how I said it’s not so much about what you eat, but when? Here’s a study from Salk University that explains what I mean:

We put two groups of mice on different eating regiments for 100 days. Both groups ate a high-fat, high calorie diet. The first group was allowed to eat whenever they wanted, grazing throughout the day and night. The other mice had access to food only for eight hours at night, since mice are nocturnal. The results were astonishing. Despite consuming the same amount of calories everyday, the mice that ate on a restricted eight hours were nearly 40 percent leaner and showed no signs of inflammation or liver disease and had healthy cholesterol and blood sugar levels. The group of mice that nibbled day and night became obese, developed high cholesterol, high blood sugar, fatty liver disease and metabolic problems.” (source, emphasis mine)

Even more fascinating is the fact that when the time-restricted feeding mice were allowed to eat freely on the weekends, they still had the same lean mass ratio as mice who were restricted seven days a week. (source)

Research on humans supports these findings – this study found that daily fasting improved insulin sensitivity in women, and this one found that volunteers who ate earlier in the day lost more fat than those who ate later in the day, even though both groups were consuming the same number of calories.

So what’s happening here? As mentioned in this post on leptin resistance and how to reverse it, our fat cells do more than just store energy and keep us warm – they secrete a hormone called leptin. When our bodies have adequate energy reserves (fat stores), leptin calms our hunger. When we need more nourishment, leptin dials up our desire for food.

At least that’s how it’s supposed to work.

When we graze all day and all night, unfortunately, our bodies often lose the ability to “hear” what leptin is telling us, and we end up feeling hungry even when we have ample energy stores. Intermittent fasting encourages better leptin signaling so our bodies get the message and we feel satiated.

#2: Activates “Cleanup Mode” ^

Intermittent fasting triggers autophagy, which is literally translated as “cellular eating.” When autophagy occurs, a bunch of little guys called lysosomes go around gobbling up damaged cells, damaged mitochondria, and cancerous cells. These lysosomes and mitochondria are good guys, giving us energy for vitality and cellular regeneration for a vibrant life. Without them, our body fills up with cellular trash and we just can’t function as optimally as possible. Furthermore, negative results like expedited aging and disease occurs because we just aren’t taking out the proverbial trash as efficiently as we should.

Unfortunately, although autophagy should occur naturally, factors like the Standard American Diet (SAD), non-stop grazing/snacking, and a stressful go-go-go lifestyle can suppress it. By intentionally triggering autophagy through intermittent fasting, we’re supporting:

  • energy production
  • free radical elimination
  • and damaged cell elimination

Here’s a real-life example of autophagy in action: This study found that fasting 13 hours per night (which triggers autophagy) may decrease the recurrence risk of breast cancer (because the lysosomes are gobbling up damaged cells).

Prolonging the overnight fasting interval may be a simple, non-pharmacological strategy for reducing a person’s risk of breast cancer recurrence and even other cancers,” said Catherine Marinac, lead author and doctoral candidate at the University of California, San Diego Moores Cancer Center. “Previous research has focused on what to eat for cancer prevention, but when we eat may also matter because it appears to affect metabolic health.”

#3: Improves Learning & Memory ^

According to this study, intermittent fasting increases neuroplasticity (brain flexibility) and the production of new neurons, which “enhance learning and memory.” This study also mentions that it dials up antioxidant defenses, autophagy and mitophagy (the cleanup of our cells and mitochondria), and DNA repair (which slows down aging).

#4: Improves Immune Function ^

In this study, mice that had been intermittent fasting had a stronger immune response to salmonella infection than those who hadn’t .

#5: Lowers Inflammation ^

One of the main causes of inflammation is an excess amount of free radicals within the body, which causes cellular damage. Throughout our daily processes of just living, mitochondria – which are the “batteries” in our cells that give us energy – get damaged. When mitochondria are damaged, they release free radicals which cause inflammation, age-related degeneration, as well as DNA damage.

Also, our energy is reduced due to the reduction in the number of functioning mitochondria. When we fast, we stimulate autophagy, which means that lysosomes gobble up these damaged mitochondria.

#6: Activates Longevity Genes ^

“We found that intermittent fasting caused a slight increase to SIRT3, a well-known gene that promotes longevity and is involved in protective cell responses,” said Michael Guo, who co-authored this study. Another study also found that it increases levels of SIRT1, another longevity gene. (source)

Is intermittent fasting safe for women? ^

The gentle version described above – a 12 hour fast overnight – is generally considered safe. However, pregnant and nursing women have different considerations. Mark Sisson reviewed the available research on pregnancy and intermittent fasting here, and I wholeheartedly agree with his conclusion: Just eat when you and your baby are hungry.

Regarding breastfeeding: In religious traditions that practice intermittent fasting, pregnant and nursing women are usually exempt from participation. There seems to be an inherent wisdom in this approach, because although I know of some women who have practiced intermittent fasting while breastfeeding (under the supervision of their doctor), I personally needed to eat during late night nursing sessions in order to feel my best.

You can read more about what we’ve learned from religious traditions about breastfeeding and fasting over at KellyMom.

My experience with intermittent fasting ^

After the birth of my third baby, I noticed that I didn’t return to my pre-pregnancy weight like I had with my first two . . . in fact, I started gaining weight. Because I was in the process of healing my adrenals, I knew intense workouts would not be my path in getting back to my normal self.

Instead, I worked on aligning my circadian rhythm by wearing orange glasses at night (to improve my sleep, which directly impacts metabolism) and practicing intermittent fasting. Even when I decreased my workouts (because busy!), I found that my body returned to my normal without changing what I eat or anything else.

Am I ready for this? ^

For some of us, intermittent fasting might sound terrifying or even impossible. In reality, gradual changes may be needed in order to transition if we’ve been snacking or eating very often.

Most of us have been told at some point that eating many small meals throughout the day is the best way to be healthy, but although there are probably exceptions based on bio-individuality and other factors, for the most part eating a lot of small meals and snacks works against our biology. Certain functions of our gut – the Migrating Motor Complex (MMC) for example – doesn’t even start functioning until 1.5-2 hours after we finish eating. The MMC is our internal housekeeper that clears excess bacteria, and we want it to clean several times a day in order to prevent inflammation and gut conditions like SIBO.

We also need breaks between eating to encourage the ebb and flow of our fat storage hormone (insulin) and our fat burning one (leptin). Eating too often overstimulates insulin and suppresses leptin. This and other factors can cause blood sugar to become imbalanced, decreasing the time we can go without food before experiencing low blood sugar.

If you have been eating and snacking often, it may take some time to adjust to this new method. That’s ok.

how to intermittent fast

How to intermittent fast ^

So how do we align intermittent fasting with our circadian rhythm to trigger autophagy? Well, rule number one is that autophagy only occurs during fasting (source). Our daily circadian rhythm requires shifts from catabolism (breaking things down, as in digestion and movement) to anabolism (building things up, as in growth and repair).

This shift between catabolism and anabolism is thrown off when circadian rhythm is thrown off, resulting in decreased prolactin, which decreases growth hormone, which decreases autophagy (source). To support autophagy, we need to align our sleep with our circadian rhythm, and align our food with our circadian rhythm as well.

Now, onto the specifics. (Note from Heather: For the sections below, I’m passing the reigns over to my co-author, Dr. Rose.)

How long should I aim for? ^

Generally speaking, we should have a 12-16-hour fasting window each day, although there are probably exceptions due to bio-individuality (source). This can be achieved by stacking our sleeping habits with our eating habits. If we are following the circadian rhythm sleep schedule, then we should be

  • eating our first meal between 7-9am, and
  • eating our last meal between 7-9pm.
  • This will require no late night snacks.

The amazing thing about this simple schedule shift in eating times is that research shows improvements in fat composition and energy levels even when the foods eaten didn’t change (source). This means that even if you don’t change one single thing you are eating, yet you align your sleep and fasting window with your circadian rhythm, you are likely to see an increase in energy and metabolic health.

What should I eat to fast safely? ^

If you start the day with your biggest meal in morning, making sure it includes ample protein and healthy fat, you should be able to start stretching your times in between meals and eventually be able to last through the entire 12-15 hour fasting window. If you include your highest amount of protein at night, you will stay satiated longer.

Again, take this in baby steps. If you currently only have a 9-hour night-time fasting window, don’t jump right to 15 hours. Increase your fasting time incrementally while simultaneously switching to nutrient-dense meals that include ample protein, fat, and veggies. Eventually, your hunger should realign with your natural circadian rhythm and you will be able to make that nightly fasting window and optimize your autophagy.

Bonus Tip: Water can help activate autophagy ^

Another thing you can do to make sure you optimize autophagy is use water at the right times. Usually we go hours without drinking water, and we only drink it with meals (if we are even drinking water at all). However, water intake can be used to better support autophagy. The amino acid leucine stops autophagy (source), so diluting it with water can activate the onset of autophagy.

Decreasing leucine also increases the amino acid cysteine, which increases the antioxidant glutathione and autophagy (source). Glutathione further supports the decrease of free radicals, further supporting the goal of decreasing cellular damage and increasing cellular regeneration. So when should you be diluting your leucine?

Well, autophagy should occur during our fasting window, so the majority of your water should be consumed during this night/morning fast. After you are done with your night time eating window, only drink water. However, you want to make sure and not drink so much water that you will interrupt your sleep. Instead, drink the majority of your water when you first wake up to further push the fasting window, support autophagy, and support free radical reduction. Then wait about 45 minutes upon waking to eat that first big nutrient-dense breakfast and let the daily intermittent fast break.

Note from Heather: I love drinking mineral water in the evening because it feels a bit celebratory and special, but I pretty much have a cup of coffee my hand right after I roll out of bed and breakfast happens shortly after that. There’s the ideal, and there’s life. Do what works for you.

Oh, and just one more thing. Breakfast = Break the daily fast. Even our language knows our circadian rhythm. It’s just a matter of adjusting our habits so we can experience the benefits of working with our biology instead of against it.

This article was medically reviewed by Amy Shah, MD, Medical Advisor to Genexa through partnership with the Mommypotamus Team. As always, this is not personal medical advice and we recommend that you talk with your doctor.

About the authors: This article was coauthored by Heather Dessinger and Dr. Lori Valentine Rose (PhD). Dr. Rose, PhD is a college biology, nutrition, herbal, and wellness instructor, Certified Nutrition Professional (CNP), Registered Herbalist with the American Herbalist Guild, and is Board Certified in Holistic Nutrition. She created, developed, and instructs the Hill College Holistic Wellness Pathway, the most thorough, affordable, degreed wellness program in the country. She loves spreading love and light, and helping others feel awesome on the inside and out so they can live their dreams and make this world more awesome!

Related Posts


Heather is a holistic health educator, herbalist, DIYer, Lyme and mold warrior. Since founding Mommypotamus.com in 2009, Heather has been taking complicated health research and making it easy to understand. She shares tested natural recipes and herbal remedies with millions of naturally minded mamas around the world. 

Leave a Comment

39 thoughts on “6 Benefits of Intermittent Fasting (And How To Do It)”

  1. My hubby and I eat popcorn most evenings, and I’m wondering if the benefits of fasting would be the same if from 10p-10a even if I go to bed at, say 11, and wake at 7??

    • You want to stop eating at least 2-3 hours before going to bed. Your body doesn’t need to be working hard to digest. I’ve done intermittent fasting for years now and IF I happen to eat too late, I feel the difference. I do not sleep as good. It’s a change that takes a few weeks to get use to but it’s well worth it. I’m 43, had nine babies and in the best health of my life.

  2. So herbal tea isn’t allowed when intermittent fasting? I skip my breakfast and eat nothing till 12 o’clock, when I eat a large meal. But in the morning I do drink herbal teas (no sugar or milk). Is that messing with my fast?

  3. I’ve been hearing more and more about this idea and I’m trying to take it all in! So much to think about, right? For so long, I’ve been hearing that breakfast is the most important meal of the day and that you should eat fairly soon after waking. It’s a bit confusing – although, fascinating – to try and figure it all out.
    So, my question is about coffee…..if you drink plain, black coffee, then that is NOT breaking the fast? But if you add cream or sugar or butter or coconut oil, then you WOULD be breaking the fast even though you aren’t chewing any foods (eating breakfast). Is that right?

    Thanks for another informative article!!

    • From my understanding black coffee is actually really good for IF….. sugar is a HUGE no no, as far as any fats, there is mixed info on it but tends to land on the side of none…. but, if that is what it takes to move you towards your goal, a splash until you can go black 😉

  4. And I thought of another question! What about adding lemon to that morning water? Does that break the fast? Thanks again!

  5. Thank you for this post! My husband just started intermittent fasting and I’m so surprised at his energy levels! He always snacked throughout the day but he doesn’t feel the need anymore. I was so intrigued by it but since I nurse (17 months) I wasn’t sure. Until I looked at my current eating window, 8am-7pm. My son only nurses in the morning and evening. Do you think it’s safe to stretch it a little?

  6. I find this so interesting because this is something I’ve been doing naturally for years. I found out a long time ago that if I eat after dinner, I don’t sleep good, my stomach feels off and I wake up ravenously hungry. If I stop eating after dinner (about 6) then I feel better and the next day I don’t feel like breakfast until an hour or two after waking up (so I eat at 8 or 9 am). It just seemed like a no brainier…. Without snacking, I was eating much less and feeling a whole lot better.

    • Me too. I could swear you’re my twin but for the past week I’ve been playing with extending the window to 16-18 hours and something miraculous has happened. I’m losing weight and I feel like my severe fatigue has disappeared.

      I didn’t realize what I was doing was intermittent fasting until this newsletter appeared in my inbox.

      Great article Miss. Effin brilliantly written.

  7. I would say yes, this works! I stopped eating a snack before bed and stopped eating dinner around 6-7 depending on schedule with my first meal being usually 8ish. In a week or so the uncomfortable gain of a few pounds were gone and I didn’t feel overly hungry and no longer felt sluggish in the tummy. I have been doing it for a few months, way before this post and I like the way I feel in doing the overnight fast. AND I’ve had adrenal/thyroid issues so this seems to be a good fit in addition to the supplementation I am doing.

  8. I keep the intermittent fasting about years and I didn’t know 😀 . My version is closer to yours 16:8 (eat the dinner early and then next day the lunch time) . Some Fridays I eat nothing until the evening (I have no time…). What I noticed is the calm of my liver, stomach, sleep better, my belly goes down (because of less gases, not loosing weight 😀 ).

    I didn’t see any loosing weight because my BMI = 21.5 so I didn’t see the difference – maybe because we have a balanced life and eat clean (farm products, I avoid supermarkets and specially the pharmacies 😀 ) and never sick in our house about years (maybe because we eat a lot of salads? 😀 , I don’t know, but I can tell you we have no snacks and walking daily -our pediatrician suggestions )

  9. Hi Heather and Lori, I’m new to intermittent fasting. Do you know what is more impacting, in terms of health benefits, calorie restriction, intermittent fasting or both? I’ve gotten different answers and not sure which is correct.

  10. Thank you for the wonderful info!!!

    I have a question:
    Does using lemon in my water affect my fasting?
    or further more,, I usually drink lemon and DE (diatomaceous earth) (or I add spirulina) on the water that I drink in the morning….
    Should I just stick with plain water?

  11. Thank you, Heather, for all the hard work you put into getting good information out there! Your articles are always fun to read, well-sourced, and relevant – I so appreciate you! I’m excited to implement fasting into my daily routine and see what benefits come about. I’ve been a fan of yours since I found your blog at 3am, years ago, while researching home remedies for a fever. Your post on fevers saved my sanity and kick-started my break-up with conventional medicine. And your posts about long-term breastfeeding – all the love!!

  12. I hope you can help me with this, so I’m a nurse and my working ours is from 8 pm till 8 am, how am I going to schedule my fasting then? Please help me to figure it out.

  13. HI I’m very interested trying this but I am a nurse working 8pm to 8 am, any suggestion on way to do it? Please help me.

  14. I have done this for several years, it just feels natural to me. I did intermittent fasting too, when I was a child and teenager, not because I read about it, I didnt know I was called anything, but I never ate breakfast. Then I started eating healthy and was told to eat all the time. I did that for many years, but never liked it, and for ten years now, I have been eating like I used to when I was younger. Mostly I eat within 6-8 hours a day. I dont drink all the time either, but more than 8 hours a day of course, but I just dont feel like it.

  15. Heather, I love reading your posts – one of the very few that I will take time to read. Well-researched and so readable. I always learn something new! Thank you for sharing your talents!

    Barbara G.

  16. Heather or anyone else with experience, have you noticed IF negatively affecting your adrenals? Like waking up at 2-3am bc blood sugar was low and adrenals kicked out adrenaline instead of cortisol to free the stored glycogen and raise blood sugar? I would love to restart IF but not sure if I need to heal my adrenals first. Bc converting fats to energy takes cortisol, which is low in some stages of adrenal fatigue

  17. Heather and Lori, I do the 16:8 Intermittent Fasting and just found you on Pinterest while I was looking for other posts, besides my own, on the subject to Pin. I fast from 6pm to 10am. Since I get up early, between 5 and 6 am, I have several hours in the morning before breaking my fast. So I do my workouts in a fasted state and have nothing but water and black tea in the morning. Not even hungry. So easy.

  18. I can confirm the longer fasting is not always better. For me, it did lead to depression, weight gain, and energy loss. I was pretty miserable for over two years. I didn’t even realize this was the cause. Once I went back to my regular diet everything went back to normal. It’s crazy how food can affect your life this drastically. 12 hour fast seems to work perfectly for me.

  19. Great article.
    Although, I think it should be mentioned that people with blood glucose imbalances should not engage in intermittent fasting. The reason being is that intermittent fasting can raise cortisol levels which in turn raises blood sugars, a dangerous situation for those with hypo/hyper-glycemia. These people should eat every 2-3 hours to ensure proper regulation of blood sugars and maintenance of good health.
    Chris Kresser has a great article which goes over this in detail: https://chriskresser.com/intermittent-fasting-cortisol-and-blood-sugar/

  20. Is it true that Intermittent fasting in combination with a low carb high fat diet is very effective in reducing and even reversing diabetes?

  21. Just curious if you did intermittent fasting while you were trying to heal your adrenals? I have hypothyroid
    And I think I also have adrenal fatigue and for the last week I have been intermittent fasting, 16 hours. I’m not sure if IF is ok for me or not because of this and was just curious if you were doing IF with the adrenal fatigue?

  22. Hello Heather and Lori! 🙂 I saw a couple of unanswered comments about nurses working 8am-8pm. My question is similar; I work at a mine and some shifts work 8am-8pm and other shifts work 8pm-8am. I am switching between days/nights often and feel like my circadian rhythm is struggling as it is. Upon recommendation of my naturopath, I’ve been doing intermittent fasting for a few months now, and am doing 19:5, 5 days a week and have found that if I eat from 4-9pm (when I work days) or 6-11pm (when I work nights) I usually can accommodate eating and my work/home life. However, this doesn’t quite align with eating ~1.5-2hrs after waking up & I’m curious if you have any recommendations for those of us whose circadian rhythm may be buggered up from shiftwork and if that rhythm is already messed up if it would matter how soon we eat after we wake? I hope this makes sense and thanks in advance!

  23. Comprehensive article. Well written with scientific resources. As a physical therapist I believe the practice of IF can aide in injury recovery, weight control, inflammation of joints and recovery from the effects of surgery.

  24. Any thoughts on how intermittent fasting works with shift work? I work 12hr night shifts and transition back to a normal schedule on my days off.