Intermittent Fasting While Breastfeeding: week one

Intermittent Fasting While Breastfeeding

I’m giving the 16:8 Intermittent Fasting (IF) a try even while breastfeeding.  I talked with both my pediatrician nurse and lactation consultant prior to doing this.  I also watched my milk supply the first few days.  The consultant said if I maintain the same amount of calories within that 8 hours, then my supply should not be affected.  I’m 4 days in, and so far it has not.intermittent fasting while breastfeeding  But here are some of the specific results that I had from intermittent fasting while breastfeeding.

Day 1

Actually started with an 18 hour fast, but this was too long.  With breastfeeding, I’d rather have my eating window longer.  I may change it after I’m done with bf’ing. I may also throw in some 1 or 2 day fasts then.

Day 2

Seemed difficult to not snack after 8PM.Going to try to move my break-fast time up to 1pm so that I can eat until 9

Day 4

Did long 30 minute interval workout (ZUzka).  Made it til 12:30 PM. Ate a couple of bad things this day, 1/2 cookie & piece of carrot cake (not together), and could really feel the impact that it had on my system.  Could it be that I’m already more in tune with my body?

Day 5

I woke up refreshed today (which is unusual for a mom with a baby still not sleeping through the night). Each day, I seem to wake up with more energy.  Did interval workout-zuzka. Done a HIIT workout every day for the last 4 days for at least 15 min.  My body has felt pushed, challenged each day but I don’t feel overly sore like I normally would.  Maybe the fasting time is giving my muscles more healing/recovery attention.  Made it til 1 PM today (12:54).  Didn’t feel like overeating really and ate something really healthy.  Pulled out some chips to snack on that afternoon, but just didn’t feel good eating them. Ate another piece of carrot cake just because I felt like I could (didn’t really want it).  Forgot I was fasting and ate a slice of apple at 9:15. Oh well…

Day 7

Woke up at 7am – wide awake and energized.  This is a first in over a year. I find myself wanting to push the fasting window a little longer.  I actually am liking the hunger and exercising my self-control.  I feel like I have self-control muscle that I am working and it’s getting stronger!  The scale has not changed much this week, but I definitely feel leaner and less bloated. I’ve also started a HIIT program and hopefully am putting on some muscle.  So “no change” on the scale numbers may mean my body composition is changing from fat to muscle. About to do a fasted workout and excited about it.  It actually makes me have better, more energized, more intense workouts.

**Really overate during my eating window on Day 7.  Even though I actually felt like stopping around 8pm, I continued to eat and overate because “I could”.  I felt miserable afterward.  I’m going to listen to my body from now on & not stuff myself just because I “CAN”

EFFECTS ON INFANT With Intermittent Fasting While Breastfeeding:

As I stated in the comments (below), I thought that Sofia had had a horrible reaction to the fasting.  I now know that she had a cold. I gave her baby Zyrtec and she was a new baby.  Basically the cold was making her overtired, then she couldn’t sleep because she didn’t feel good. Poor baby!  But now that the cold has almost entirely cleared up, she is her usual cheerful, bright self.  I have seen absolutely no negative effects on her doing intermittent fasting while breastfeeding.

MILK SUPPLY With Intermittent Fasting While Breastfeeding:

Sofia is actually nursing for shorter amounts of time and with longer periods in between feedings.  She is not acting fussy (she had a cold on Days 1-4 of this week) at all anymore. If it’s possible I actually think intermittent fasting has increased my milk supply. I also did not feel that intermittent fasting while breastfeeding was overly taxing on my energy. Now, I will state that Sofia is 8 months old, and while she is still almost exclusively breastfed, my supply is definitely established. And I’ve never had any kind of supply issues.

WEIGHT LOSS With Intermittent Fasting While Breastfeeding:

My weight bounced up and down between 163 and 165.  So, no weight LOSS exactly this week. But I read in The 4 Hour Body that with intermittent fasting weight loss does not begin until after the 3rd week and it continues to be around 1lb. per week after that point.  I’m also still in a “learning” phase of this lifestyle. For example, when I overate on the 7th day.  This may impede my weight loss as I learn the amounts and kinds of foods that my body really needs. I definitely feel the fasting will aid my weight loss.

Another factor in weight loss results is I have started high intensity interval training.  The goal of this type of training is to gain strength thereby MUSCLE.  Although a pound of muscle is equal to a pound of fat , it takes up a LOT less space. So, while the scale may be staying the same, I may just be trading muscle for fat which is good! And an added reason for no scale change is that with intense workouts, workouts that really challenge muscles as HIIT does, can cause an increase in weight.  The reason is because water rushes to those micro tears in the muscles.  This increases your retained water weight for a period of time.  And trust me–I been tearin those muscles UP!!!!


This is my AFTER pic but also my BEFORE pic since I’ve lost all the baby weight but intermittent fasting while breastfeeding I’m also just starting out on IF, Xyng, and HIIT. Xyng is like a pre-workout supplement.  It’s definitely helping me in the intermittent fasting and HIIT workouts.


  1. Right out of the box I’m going to stay to stop taking the Xyng immediately. It’s not recommended for pregnant or nursing mothers. I would be very concerned about it leeching into your breast milk. “Natural supplements” aren’t regulated by any governing body. There’s no telling what might be in there that’s not listed.

    Regarding the fasting, I think that if you’re not noticing your milk supply suffering, you shouldn’t have an issue, nutritionally speaking. Make sure that when you’re eating, you’re (duh) eating mostly healthy and balanced foods. Try upping your calorie intake during your allowed eating time if you notice that it’s starting to suffer or adjust your fast/eat times. When you do get to eat, try to eat some additional healthy fats (avocados, nuts, etc). Does the fasting mean you can’t have water during that time either? Keeping well hydrated will play a big role in your milk production, even more so when your calorie intake changes.

    If your production does start to slow down, you won’t necessarily notice right away. Keep a look out for her being more fussy/behavioural changes, nursing for longer periods of time, peeing and/or pooping less frequently, dirty diapers appearing more yellow, and firmer stools.

    I wouldn’t generally recommend this type of diet to someone who is breastfeeding, but if you don’t see any changes to your milk, your daughter’s general digestive health, and/or behaviour, you should be good to go. Please don’t take the Xyng though.

    Good luck! 🙂

    1. Yeah I’m going to start supplementing using Xyngular’s other products next month. I’ve really loved the boost in serotonin that the Xyng specifically gives but I’ll wait to start back up once she quits nursing. They have many other products that are helpful in losing weight and getting healthy that don’t have any risks for nursing moms.

      I eat a ton of those good fats you listed. (Probably a little too many. Heehee) And I also eat a pretty high number of calories within the eating window. Usually at least 3-4 meals of 600+ calories. So far, so good as far as milk supply. I have to pump during work days and I seem to be producing the same or maybe even better.

      Thanks so much for your help!

  2. I blog frequently and I truly appreciate your content. The article has truly peaked my interest. I am going to book mark your website and keep checking for new information about once per week. I subscribed to your Feed as well.

  3. Oh my! Was your infant really ok? Your post sounds tenuous! I would have been extremely concerned that your infant was breastfeeding for shorter periods of time with longer intervals between and was overtired. Our infant was feeding poorly and ended up in the hospital with jaundice and dehydration when we started breastfeeding because of poor latch (trying to breastfeed exclusively). Unfortunately, he was also a happy-to-starve infant. We tried following his feeding cues (hand sucking, tongue sucking, smacking etc., but had to switch to feeding on a schedule (every 2h during the day and every 4h during the night). We also had to switch to formula and bottlefeeding pre-measured amounts of breast milk to make sure he was getting enough food. I investigated this as a new christian, thought it would be appropriate to fast for a social concern, but found that all religions addressed on excuse breastfeeding women from fasting (though it does state that short fasts are probably not a problem). It would be interesting to know what occasion made you try fasting and breastfeeding. I would have shifted to bottle feeding in your situation (measuring the amount you feed) and pumping while fasting to ensure that your baby was receiving enough milk. Never heard of exercising and fasting at the same time. Not sure it is a good idea. I don’t have the time, energy nor resources to investigate this further, but there were a good number of references in the kellymom article. Accessed: 16 March 2017 via a Yahoo search for fasting and lactation (would have used google, but to my frustration yahoo has somehow taken over my computer, though my settings indicated google is my preferred search engine… Can’t fix it myself…)

    1. It’s different for everyone. I have always had great success with fasting and breastfeeding. If anything my supply goes up while intermittent fasting. I have 3 children, still breastfeeding the last one who is 18 months. They were all breastfed over a year. I practiced intermittent fasting with all of them. Sometimes it wasn’t daily, but maybe 3-4 times a week instead.

  4. I found this very interesting. I used intermittent fasting after my second baby (wasnt breadtfeeding though) and i was in the best health of my life! Im now bf my 3rd whose 3 months and have started decreasing my eating window this week. I wont eat after 8pm and usualy eat again about 9am/10am the next day. I wont go beyond that for a while though just incase my supply dips but so far so good! I usually find 16:8 with my first meal a vegan style protien smoothie works best for me!

  5. I’m really glad i found your site! So, would you recommend 3-4 days of fasting as a general rule while breastfeeding? Also, we are almost at the year mark so how does IF work when not nursing? Daily?

  6. Thank you for this post. I’m reading, The Complete Guide to Fasting, and I’m following the Facebook page and they are all against doing it while breastfeeding, but I function so much better and my milk production is better when I do. When I go back to eating before noon each day, it drops. I’m not sure why. I eat as healthy as possible, lots of steamed or raw vegetables and meat. I do eat my lactation cookies, but when they’re gone I’m going to stop making them and see how things go. I need to cut out the sweet. I fast for 16 to 24 he’s and I really have more energy and a better mood when I do so.

  7. First off thank you for sharing your experiences with us! There arent too many blogs about nursing mums who are doing IF. Secondly, I too am exclusively feeding my 2 month old infant and have started the 16:8 IF (I wanted to try the 24 hours one but the mums on the IF group on facebook recommended against it). I am on day 3 of 16:8 fast (a night ago I had an assignment and it was freezing cold so I had LOTS of junk food as I felt I was starving!).

    But I have to say contrary to what I thought I am not starving by 12pm! The first 2 days were bit difficult but today I feel good. Also I take a isolate whey protein shake (the best kind of whey protein) which gives me 24g of protein in a serving and I believe that really helps in terms of body functions and my appetite. I have not tried working out as I have a toddler at home as well but HIIT working sounds good as its only for 15 mins!! Please share which one you do (if there are any videos or website link you follow)

    And btw looking at your pic I wouldn’t even have guessed that you have had kids! You look great 🙂

    All the best!

    1. Thanks! Yeah I wouldn’t recommend jumping in to 20/4 at the start of breastfeeding. I would let your fasting window grow organically. Now my fasting window is just a natural reaction to my life. With 3 little ones, my most peaceful time to eat is either during nap time at 1 pm and after their bed time which is 7pm. These times I can eat in peace (and it’s not a handful of goldfish lol).

      1. Hey Sarah! Are you still IF-ing? Has it affected your milk supply at all? My little is 2.5 months and I want to try it, but I’m worried!

  8. Thank you so much! I am breastfeeding and I started IF today with a 20:4 window. I drink small amounts of green juice and berries throughout the day, with about 3 hours between each “snack”. The author of the military diet has made compelling arguments about including small amounts of either coco water, green juice or berries, spaced by at least 3 hours and then only having one large meal at night or a 20:4 window. I felt incredibly amazing!!!

  9. I would be interested to know what you ate each day during your 8 hour eating window. Any chance we could see a food log of sorts or even a guess for one of the days?

  10. Hi! I am so interested to try out IF. I am breastfeeding my 5 month old and supply is pretty much established. Have a few questions which I hope you can help me out with.

    1. How do you suggest I start out? I want to gradually ease into. 16 hours fasting to 8 hours of eating scares me as it might cause a dip. Can I do 12:12 first?

    2. During the fasting window, I can only drink liquids that do not contain calories right? No snacking allowed?

    3. During the eating window, this is the only time I can plan out my meals right?

    Appreciate your reply 🙂

    1. Tahnee,

      12:12 is fine. I have a getting started post on here that talks about gradually increasing your fasting window. It works. I just keep increasing until I’m losing weight.

      It is really flexible. For weight loss. Eating a handful of something that is under 50-100 calories has not ever hindered my weight loss. It does interrupt thereby cost you some of the pure fasting benefits.

      Eating window is the only time to have meals. Yes.

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