Lose Weight Postpartum Intermittent Fasting While Breastfeeding

intermittent fasting while breastfeedingLose Weight Postpartum | Intermittent Fasting While Breastfeedimg

My Postpartum Weight Loss Journey

I was warned off immediately from fasting while breastfeeding even intermittent fasting such as eating during a 6 or 8 hour window (fasting for 18 or16) or a full 24 hours once/twice a week. As for intermittent fasting while breastfeeding, since I wanted to begin IF while nursing, I first considered things like established milk supply and breastfeeding history.  I was oddly lucky in that no matter how much I exercised, or how little I ate, I kept a steady oversupply of milk.  I also wondered about the fact that there are women who have breastfed just fine during famines. I personally think the whole you must eat an extra 500-800 calories while breastfeeding is slightly over exaggerated. And I think trying to eat that way contributed to my having a hard time losing the baby weight. I probably could have maintained my normal eating of around 2200 calories and still nursed. But of course, this is all based off my personal experience with breastfeeding, I definitely wouldn’t recommend this for a mom who may have trouble with nursing. Source

Here is a link to my first week’s experience in Intermittent Fasting while breastfeeding.

And my personal journey to lose weight postpartum

The benefits of intermittent fasting such as Lean Gains and Eat Stop Eat method are inticing to me. Since I wanted to begin intermittent fasting while breastfeeding, I decided to research what the possible effects would be to my milk and milk production as this is my first concern.

Intermittent Fasting While Breastfeeding: Milk Consistency

It seems like many people suggested my milk would turn to crap or poison if I began a fast that was longer than 16 hours.  I decided to look at some studies that studied the makeup of lactose/milk after a fast like this.  Here is some info from one study done on Muslim women fasting during Ramadan. Muslim women, while not required to fast, often fast during Ramadan (which is 40 days long I believe).  This would be a dinner to dinner type of fast that programs like Eat Stop Eat purports.  Here is a clinical study done on the quality of breast milk of fasting moms:

In one such study conducted in the UAE at Muwajihi Primary Health Care Clinic, milk samples were taken from healthy breastfeeding mothers, during and after Ramadan. It was discovered that fasting did not significantly affect the level of “macronutrients”. These are nutrients needed in large quantities for growth and energy – namely proteins, carbohydrates and fat. Fasting did affect the level of “micronutrients” – but these are by definition only needed in small quantities, such as magnesium, zinc and potassium.

Sharjah Baby Friendly Emirate Campaign, remarked, “Breast-milk is incredibly resilient, and can retain its major nutrients even during fasting. It’s crucial to maintain the same breastfeeding pattern during Ramadan, to give the baby a sense of continuity and rhythm. If a mother chooses to fast, it’s vital that she replenish her nutrients with a balanced diet encompassing all the major food groups when she breaks her fast each day, and revert to her normal eating habits immediately after Ramadan.”

Here is a study on fasts LONGER than 24 hours. This study was done on breastfeeding moms with babies of 1-6 months old.  They took samples from 2 days before and immediately after the mom did a fast of longer than 24 hours. The changes to the makeup of the milk were as follows:

  • Sodium, calcium, and Protein increased
  • Phosphorus and Lactose decreased
  • Triglycerides (fats) were unchanged

After reading about milk consistency of hindmilk & foremilk like here:

This higher-fat hindmilk mixes with the high-lactose foremilk and baby receives the perfect food, with fat calories for growth and lactose for energy and brain development. (1), (2) However, when milk production is too high, baby may fill up on the foremilk and then have difficulty digesting all the lactose that is not balanced by fat. This is known as foremilk/hindmilk imbalance or oversupply.

So the lesser quality foremilk, is higher in lactose.  It would seem that the milk is changing it’s makeup. Rather than increasing the triglycerides which were unchanged, the protein is increased.

Intermediate Fasting While Breastfeeding: What about Milk Supply?

Okay.  Another thing that even a lactation consultant told me is that my milk supply might be immediately & permanently effected by fasting (meaning it would  go down). I also researched this in another study,

the increased glucose demands of lactation are met by increased GPR as a result of increased glycogenolysis but not GNG (non-carbohydrate) or by increased use of FFA. During feeding, lactating women handle oral carbohydrates normally but have increased insulin sensitivity.

What the heck do all those big strange words mean????

GNG stands for Gluconeogenesis and is usually associated with ketosis (like when you’re on a low-carb diet). This process was actually 50% higher in the fasting lactating women.

Glycogenolysis is the breakdown of glycogen to glucose.  The speed of this process is GPR

GPR stands for glucose production rate.  Where glycogen/sugar is made more available by being made faster into glucose in the liver.

FFA stands for free fatty acids which basically just means fat.

* the increased insulin sensitivity is interesting to me.  This is always a good thing.  It’s how you’re body reacts to sugar in the blood and keeps it in balance.  It’s always good for this to be increased. After a fast, these moms were left with this good quality.

More from this same study: the primary, but not exclusive, source of milk lactose, is plasma glucose.   Lactating (L) women may provide approximately 60 g of their glucose pool to meet their infants’ milk (lactose) demands.  Basically, there are four factors or possible adjustments the body can make to the fasted state.

1. The breastfeeding mom has to produce more glucose than a non-breastfeeding mom

2. The breastfeeding mom has to reduce her own body’s use of glucose (ketosis starts sooner)

3. The breastfeeding mom could develop low-blood sugar.

4. Or milk production could go down.

This study found that…

the primary mechanism for maternal adaptation to short-term fasting is decreased maternal glucose use by the early development of ketosis and fatty acidemia, thus maintaining a glucose supply for milk production and a constant                  milk supply for the infant.

So ketosis begins sooner and milk supply is not affected

stretchmarskhelp.com About Peeing After Sex



Other sources:

BBC on Intermittent Fasting and Here also

KellyMom on Breastfeeding while Fasting





  1. Hi there,

    I am really pleased to have found your article .

    I am a tandem ( 20 month and 3 years old) constantly nursing mum.

    I too always had oversupply. I was on a Dukan diet ( low carb and low fat ) and no affect on breast milk, good weight loss. Three weeks ago I moved onto 5 2 diet, but so far zero weight loss..

    I am searching the internet to find wether IF can be crushing with my breast feeding hormones and slowing my metabolism down??


    1. Every body is different. I have read on Mark’s Daily Apple that IF can have an opposite effect on women. I did not do Eat-Stop-Eat or 5-2. I only ate between the hours of 2-3pm and 10-11pm. I just could not fast for a whole 24 hours while breastfeeding. It made me feel too weak. I definitely still lost with the 8-hour window of eating each day, and it did not affect my supply. I would take days off of IF though (probably about once every 2 weeks). So maybe you could rotate some normal eating days in there. Next, I would try recording what you are eating for a week or so. Use My Fitness Pal if you use apps. It’s great and makes journaling food easy. It may be that your calories are just way too high on the days that you are eating. Let me know how it goes! I pray you much success.

  2. Thank you so much, so grateful for your article. I have been breastfeeding for the past two and a half years and now feeding my 2 year old and 3 month old, but still not able to lose baby weight. I have always wanted to try IF. What I’m mainly concerned about is that I’ve heard that your body apparently releases toxins when you are fasting and that gets into your breast milk. Do you know anything about this?

    1. Elena,

      It depends on the length of fasting that you are doing with IF. I think with LeanGains (16/8) you should be fine. Really, if you think about it everyone does intermittent fasting daily unless they are waking up in the middle of the night to eat. So, I don’t see how toxins would be released at a dangerous level any more than are normally released during the body’s natural cleansing process, nightly. Now, as far as the every other day or 36 hour fasting, that I’m not sure about. I always did 20/4 and 16/8 without problem.

  3. Hey, thanks so much for this! I’ve been investigating IF but have been breastfeeding and concerned about everything… this was a very informative and helpful article!

  4. Hi, have you come across any information of any toxins getting in your milk if your body starts to detoxify while doing IF?
    My toddler is 21 months old. My milk is not his primary source of nutrition anymore so i am not that concerned about it lacking something for a short period of time, but rather about it containing some toxins (if it makes sense).
    I find it is very hard to come across any information backed up by research.
    Thank you!

    1. All the research I’ve found online or by questioning doctors is that the breast is the BEST filter. Very, very little ever gets through. Any study on breastfeeding and toxicity has been on medicines. They have to give test subjects (usually mice) an ungodly amount of meds for the baby to get anything harmful. Also, unless you are doing an extended fast I don’t think the detoxification that would be happening would be very great. I mean women normally fast for at least 12 hours or so daily while sleeping. We are just extending that a bit. Now, that said, I don’t do extended fast while breastfeeding (longer than 23 hours).

      1. So, I have been researching this same topic; breastfeeding a toddler who’s primary source of nutrients is not breastmilk. I also thought that the body “filters” the toxins away from the breastmilk. IF that’s so then what about all the findings of the woman in Japan who had radiation in their breastmilk and radiation was also found in cow’s milk on the West Coast after Fukashemia.

        1. Some toxins do get through the milk barrier. You would just have to research this. They are usually given a classification of “C”. I’m sure patients in radiation therapy are probably told not to breastfeed. In this post I’m really only talking about the body’s natural detoxification processes that occur on a daily basis.

  5. I love you so much right now!!! Before I was pregnant, I lived my life around IF and working out. I’m a week postpartum now, and would love to get back into it, but didn’t want to do the research myself. So thanks a million for taking the time to look at all these studies and even try it for yourself. I’ll probably wait another 2 or 3 weeks or so to establish milk supply, but I’m excited that the science is on my side! Thanks again!

    1. Hi,
      We have little ones around the same age and I was wondering how the IF reintroduction went? I am interested in trying the 16/8 protocol. Thanks!

      1. I took a long time to get back into it this time. I just mixed in one or two 16/8 days a week. Now I am doing it pretty much every day and throwing in some longer fasting window days (20/4, 18/6). My body was just not responding well at first. Now I’m 10 months postpartum and feel good doing it finally.

  6. Hi!
    I love your post! Thank you for all the info. I did IF before I got pregnant and I am not 6 weeks postpartum. I am wanting to start it up again because I know how amazing I felt on it before, but wondered if it would be best if I waited till my son is a certain age ? I also have an over supply of milk and have been working with a lactation consultant and even trying to lower my supply. Do you have any suggestions as to how long I should wait before I start IF? I absolutely don’t want to jeopardize my milk either!
    Also Do you have any updates on your results?
    There is a micronutrient supplement that I have been using that is 0 calories that shouldn’t “break my fast” that could be taken during IF so my milk doesn’t lack those nutrients from the fasting state! I just use calcium plus powder from any health food store.
    Maybe a solution? 🙂
    Thanks in advance for any feedback!

    1. It wasn’t my milk supply that was a problem. I’m usually an over producer. But I thought that doing intermittent fasting every day was affecting me mentally. I’ve gotten to a point where I feel more stable and balance whether it has to do with hormones or whatever. So when I was first postpartum and started I F I think at six weeks I threw in one or two intermittent fasting days of a 16 hour fasting window. Some weeks I wouldn’t do it at all depending on how I felt. Now I am finally 10 months postpartum doing it regularly and feel good doing it. I’m also at pre-preg weight and still losing steadily.

  7. Hi! This was very helpful. What do you think about milk supply’s response to a consistently lowered caloric intake? I’ve been forced this past week to ration a lot of my food when I couldn’t afford groceries after rent. So I’ve been tracking calories and seem to be getting about 1000 per day the past 3 days. Humans raised babies through famines right? I’m not starving but just very hungry. And so far my 2 month old has been satisfied. I just feel so guilty for not eating enough but what I do eat has protein and healthy fat (hotdogs,eggs,peanut butter, bread) plus I take a multivitamin. Should I worry about losing my milk supply?

    1. My mom breastfed me and my brother until we were almost 2 on very little money/food. She said while he had rolls, family was worried about her looking like a skeleton. I think every body is different, but most of the time baby will get what he needs. Have you ever shopped at ALDI’s? You can get produce really cheap there. And beans are a great cheap, nutrient & protein-dense food. I wouldn’t worry. Just do the best you can. It’s only a season. God has days of favor and open heavens coming for you, Cassie.

    2. Hey Cassie, I just want to send some love to you since I am in a similar position. I prayed for you and know your situation will change. I know you may already be aware but just in case, try to get Food Stamps or if you are over the income limit for that, see if your state has a WIC (Women Infant and Children) program. They allow all kinds of benefits for breastfeeding moms and their income limits aren’t as strict. They provide fruit, milk, cheese, eggs, …that sorta thing. Love to you and your beautiful baby.

      1. In Texas you HAVE TO vaccines your child in order to get any benefits beyond Medicaid… ? I’d rather starve than inject my kids with poison!

  8. I started IF 5 days ago and I realized I’ve been practicing it the majority of my life. I really got into the whole eating 2-3 hrs crap 7 years ago and found little to no success with losing weight. However during that phase, should I miss a few meals I saw progress quickly. But I always thought it was the wrong way to go. Now I see differently. Your article has been a lifesaver because I currently breastfeed and I want to stick with IF. I honestly believe my milk supply has increase within iF. I had lost my supply a week ago due to traveling and not pumping to keep my supply.

    I was about to quit breastfeeding all together cause tryi b to get my supply back was exhausting and discouraging. However after starting IF it came back immediately and my baby is fed while I don’t eat as much as I used to.

    And before IF, I wasn’t getting a good amount of breastmilk. It’s funny, that my milk has increased since IF.

    Your article helps a great deal and eases me my mind as to what I’m doing. I’m looking forward to the great results I’ll have with IF.

    1. I feel like my supply might have increased with IF too. Isn’t that weird? I think I eat a more nutrient-dense diet and make healthier choices with I am practicing Intermittent Fasting. Maybe that’s why?

  9. Hi there, thanks for this info it’s very useful! I wanted to ask if you thought doing an 18-hour fast everyday for 30 days would affect breastmilk supply or quality? I’m considering fasting next month for Ramadan and the fasts are going to be quite long but I don’t want to reduce supply/quality as my baby is 7 months old and doesn’t eat solids yet (she spits the food back out!) please let me know what you think.

    1. I have fasted that much and it did not affect my supply that I could tell. Just focus on nutrient-dense foods during your eating window.

  10. This article is so interesting! Considering myself a veteran faster, though I haven’t done it since before I was pregnant until now. I’ve been fasting 16-18 hours a day for the last couple weeks, baby is 4 months old. My milk supply seems unchanged, but much fattier! My baby also seems to be satisfied longer between feedings. Also, my energy levels are back up, despite not sleeping as much which is great. So far so good.

    1. Hi Toni how are you getting on ? Are you still feeding and IF? My daughter is 10 months old and I’ve still got a few sticky pound that won’t budge x

  11. What are your thoughts on IF whilst pregnant? Currently have 4 weeks till guess date. If you think it may not be a good idea until baby is born, how do I start? When to eat and how long to fast for? Any recommendations for this? I’m a complete newbie to IF. My husband has done it for a week and the changes to his body are incredible. Thanks x

    1. I have researched IF while pregnant. You would want to look up Ramadan and Pregnancy. Some muslim women practice IF during Ramadan which I think is 40 days at the end of their pregnancy. I believe that in that research it said that there was an increase in going into labor early (like 37 weeks). Keep in mind, some of those women also do not drink water during the fasting window. I would research it for yourself though. If you have had normal pregnancies before, it would probably be fine. Make sure you are taking in nutrient-dense foods and adequate calories during your eating window.

    2. I don’t know, personally, I wouldn’t fast while pregnant, especially late into the pregnancy. MAYBE a day here or there every other week or something if you want to keep weight gain in check, but honestly, there is a time for everything. While pregnant, a baby is developing in such complex ways that it’d be a shame to deny an unborn baby what it needs just to keep off a couple LBs. The little ones brain develop a lot near the beginning and the end as well. I’m 6 months PP, breastfeeding, and doing IF and the weight is falling off. It will happen afterwards if you’re committed to it once the baby is born. To be frank though, I’d wait till you have an established breastmilk supply as well, which for me was I’d say a month PP at the earliest, unless you are not planning on breastfeeding, then have at it. Your body will be recovering after birth though so keep in mind that you deserve to be nourished while recovering from something so hard on you body. There is a time for everything, and pregnancy is a time for life giving. Afterwards it can be a time for weight losing and it will happen if you do IF.

      1. Some women have much better milk supply while intermittent fasting. I have heard them say supply goes down when they are not! I am this way. I’ve wondered if it’s because my body can focus on milk production rather than digestion/ food-energy conversion (which is very taxing to the body). That leads to my next point. Intermittent fasting is not just about weight loss. It is so much more: freedom from food addiction and cravings, having more time and more creativity, hormone balance, better sleep, pain-reduction (arthritis, joint, muscular), better dental hygiene, stronger immune system, longevity, disease-prevention, improved circulation … There’s a lot more, but i think pregnancy is a time when mom strongly needs these other benefits. Your body will not lose weight beyond what is healthy during pregnancy if you are eating what you are hungry for/craving during the eating window.

  12. Thank you for this post & the earlier one you did! I’ve been wanting to take advantage of the benefits of fasting, but thought with a 9 month old still feeding a lot of the time I shouldn’t. Good to hear that the whole ‘you shouldn’t burn fat while breastfeeding because of the toxins’ thing isn’t true after all (for the most part).

  13. I just wanted to chime in with my experience of doing a 21 day water fast last year (while breastfeeding my 2 year old)…

    I started with IF and there was no change in milk; I felt amazing! As I learned more about fasting I felt called to do an extended water fast. Since there isn’t a whole lot of info on extended fasting and there is little to no info on it while breastfeeding… I kinda just had to go with my gut! Like I said, I felt “called” to do it so I wasn’t too concerned about harming my child since 1) he didn’t need the milk and 2) I felt Good was telling me to do it. ?

    I never lost supply… In fact it increased bc I was drinking so much water!! Whether or not there were detox toxins in my milk… I don’t know. I will say that doing an extended fast is totally worth it!!!

    1. Yes! Our instincts are so strong. And faith…I also had increased supply when fasting. Weird, but I’ve gotten that feedback from many other fasting moms!

  14. Hey!
    I’m exclusively BF my nearly 6 week old baby boy. I started my fast yesterday and only intend to go till tomorrow, and I’m eating of a night.. but not copious amounts of food. Though, I will eat till I’m satisfied.

    Is it going to be counterproductive to drink water and mother’s milk tea throughout the day of fasting or not?
    Also, I’m wanting to get back into exercise by starting off with gentle exercise (walking for about 20-30 minutes). Is this a good idea?

    1. Water and tea is a great idea. Gentle exercise is always my recommendation when you first start intermittent fasting. Especially for women, it’s important that we ease into it because of how strenuous exercise can affect stress hormones (because IF causes changes to many hormones).

  15. Wow…thank you so much. You answered all the questions in my head..i want to try IF but im worried that my milk supply will affect…Now that ive read your article, im confident to do it. Thank you so much. You’re an angel.

  16. Hello! I love this post!!! I don’t know why I just saw this now!

    Question is: During the fast period, do you just take in water? For the milk supply?

  17. I am a young mom trying to get to my weight goal of 105, I am currently betwen 120 and 118. I feel like i just cant loose these last couple of pounds, I know people are going to say I don’t need to loose weight being I am 18 and 5’2 in height but I look in the mirror and I just want to cry. I want to try the 16/8 fasting method but I don’t want to hurt my daughter in any way. She is 10 months old and she loves solids more then breastfeeding in my opinion. I’ve read your article and I think this is the most helpful one out there! Thank you for taking the time to write this I appreciate it. If anyone has any tips or comments please feel free.

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