Many religions encourage fasting as part of the ritual of some major holidays. For those of the Jewish faith, fasting occurs during Yom Kippur. Muslims traditionally fast during Ramadan. Some Christians fast for Lent. And religion aside, diets like intermittent fasting have become more popular. But is it safe to skip out on meals when you're pregnant or breastfeeding?
Of course, fasting for religious reasons is different from fasting for weight loss. But here's what you need to know if you're pregnant or breastfeeding and considering fasting.
Is it safe to fast during pregnancy?
Fasting during pregnancy is a delicate balance. Growing a baby increases your nutritional needs by around 300 to 450 calories per day.[1] And some research has shown that abstaining from eating for any length of time when you're expecting can lead to the production of ketone bodies, molecules produced by the liver during periods of low food intake that may have a negative impact on the fetus.
Considering those risks, your best bet is most likely to steer clear of fasting while you're pregnant. And you shouldn't feel guilty: Many major religions give moms-to-be and lactating women a pass.[2]
That said, no two pregnancies are exactly alike, so if fasting is important to you, start by talking with your OB/GYN about whether or not it's safe for you and your baby-to-be if you fast. It may depend on certain factors, like the trimester you're currently in or any underlying medical conditions you and your baby might have.
No matter what you and your doctor decide, staying hydrated is key during pregnancy. Water plays an important role in your baby's development, so at no point should you stop drinking water. Dehydration can lead to low amniotic fluid, preterm labor and other complications.
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If you and your doctor decide that fasting is safe for a short period of time, make sure you drink at least eight glasses of water a day and avoid any strenuous activity that may cause a loss of fluids.
Is it safe to fast while breastfeeding?
Breastfeeding bumps up your energy needs even more than pregnancy. Nursing moms should take in around 450 to 500 extra calories per day — which can be tough to do while fasting.[3]
Ultimately, you'll feel your best and protect your supply by avoiding fasting altogether. And again, keep in mind that most major religions exempt breastfeeding moms from periods of fasting, so you shouldn't feel bad about skipping out.
That said, most experts agree that fasting for one day does not impact milk production or impair the health of either mother or baby if both are healthy beforehand. Moms should increase their fluid intake before beginning their fast and limit intense exercise while fasting to avoid burning too many calories unnecessarily.
Once you feel thirsty, you're already mildly dehydrated, so nursing moms should make sure to drink enough fluids to avoid getting to that point. Get into the habit of drinking a glass of water each time you breastfeed and then a few additional glasses every day while you're fasting and after you're finished.
But prolonged fasting while breastfeeding should be avoided because it could possibly decrease milk quantity, which over time can slow your baby's weight gain. What's more, it's not a good idea to fast immediately after giving birth, while mom and baby are still recovering from delivery and establishing maternal milk supply. Following a healthy breastfeeding diet is crucial, so fasting for any extended period of time isn't good for you or your baby.
Can fasting impact your milk supply?
Fasting for short periods likely won't decrease your milk supply, research shows. Your body will go to great lengths to continue making milk for your baby, even if you're taking in little to no calories. But that doesn't make fasting a good idea.
Why? Ample evidence shows that the nutritional quality of a mother's milk is largely determined by her diet. When you take in fewer calories, you consume fewer vitamins and minerals overall. And the result can ultimately be less nutritious milk.
Keep in mind, too, that breastfeeding is physically demanding on your body, and having a steady supply of calories ensures you have the energy to function at your best. There's a good chance that fasting will leave you feeling sluggish — which can be tough to handle when you're caring for a baby or toddler.
Also, while fasting probably won't cause a dip in your supply, not getting enough liquids will. So if you choose to fast, make sure you're still drinking plenty of water to prevent dehydration.
Is intermittent fasting during pregnancy safe?
Intermittent fasting — fasting for periods throughout the day — is sometimes touted as a way to lose weight. But you should never try to lose weight when you're pregnant.
Regardless of where you started pre-pregnancy, it's healthy and important to gain weight while you're expecting to support your growing baby. Your doctor can provide a personalized recommendation as to how much.
Since intermittent fasting is meant to help with weight loss, there's simply no good reason to do intermittent fasting while you're pregnant. And like fasting in general, it could potentially have a negative impact on your baby's growth and development.
If you're concerned about your weight during pregnancy, talk with your OB/GYN. Together, you can determine whether you're putting on the right amount and discuss strategies for what to eat during pregnancy.
Is intermittent fasting safe while you’re breastfeeding?
Intermittent fasting hasn't been studied in breastfeeding women, so experts can't say for sure whether it's a safe, healthy way to lose weight. And like with other forms of fasting, going for long periods without eating at a time when your calorie needs are higher than normal could leave you feeling sluggish and low energy.
You might be eager to return to your pre-pregnancy weight, but try to be patient. Since breastfeeding burns around 500 calories a day, you just might find that with some time, it may happen without any other significant changes on your part.
And if you do want to try other steps? Experts agree that it's safe to try to lose weight while breastfeeding, provided your milk supply is fully established and you take a slow, steady approach. That means waiting until you're at least six to eight weeks postpartum and aiming to lose no more than 1 pound a week by continuing to eat enough calories per day.
Instead of trying intermittent fasting, fill up on a healthy breastfeeding diet, and find a form of postpartum exercise that you love (after getting your provider's okay to work out again).
Tips for fasting
Whether you're expecting or you're a new mom who's breastfeeding, it's important to nurture your body so you have what you need to take care of your baby. While you shouldn't fast for weight loss, if you're considering fasting for religious or cultural reasons, these tips can help:
- Talk to your practitioner ahead of time. Remember, every mom is different. That's why consulting with your doctor or midwife is so important before you fast.
- Stay hydrated. Dehydration is risky business for both moms-to-be and nursing moms. Drink extra fluids before fasting and then make sure you're hydrated throughout your fast.
- Avoid long periods of fasting. Fasting for prolonged periods of time can impact your fetus if you're pregnant and potentially your milk production if you're breastfeeding. These delicate periods of development are not the time to fast for more than a day.
- Take it easy. There's a good chance you'll have less energy while you fast, so steer clear of strenuous activities or exercise.
- Listen to your body. Rest when you feel sluggish or fatigued. And if at any point you start to feel lightheaded or weak, you should eat.
It may be okay to fast for religious or cultural reasons while you're pregnant or breastfeeding, provided you get permission from your provider, stick to brief fasting windows and make sure to stay hydrated. But now isn't the time to fast longer than a day or fast for weight loss.
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