Keto For Pregnancy And Nursing: Is It Safe?
Women's Health

Keto For Pregnancy And Nursing: Is It Safe?

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Keto For Pregnancy And Nursing: Is It Safe?

Posted 2 years ago

Brian Stanton

Brian Stanton


Ari Magill, M.D.

Ari Magill, M.D.

Scientific Reviewer

Expert Approved

If you’re pregnant, nursing, or expecting to be, you might be wondering if Keto is healthy for these pivotal periods. Is Keto safe for pregnancy?

It’s worked for many moms, but that doesn’t mean there aren’t risks. And it also doesn’t mean that low-carb diets will work for every expecting mother. 

This article will help provide some clarity. By the end, you’ll be able to decide if Keto makes sense for your prenatal and postnatal journey. 

What Is Keto?

Keto is short for the Keto diet. The Keto diet (or ketogenic diet) is a low-carb eating plan in which you eat 55-70% of your calories from fat, 20-35% from protein, and under 10% from carbohydrates. 

By keeping carbs low, you send a powerful fat-burning signal to your cells. This signal—triggered by low blood sugar and insulin levels—breaks apart body fat and sends it to your liver where it’s burned to make energy and ketones.[*

Keto is best known as a weight loss diet. On a very low-carb diet, people not only tend to consume fewer calories, but also expend more energy.[*

Why do people eat less on Keto? Because low-carb diets reduce hunger hormones like ghrelin and neuropeptide Y.[*

Remember this point about Keto, appetite, and food intake. It will come up later when we talk about prenatal and postnatal nutrition. 

Proper Nutrition During Pregnancy and Nursing

While pregnant or breastfeeding, a woman needs more of everything. (Love, hugs, understanding, etc.). And nutrition-wise, she needs more:

  1. Calories
  2. Protein 
  3. Micronutrients

Let’s review these individually. 

#1: Calories 

Pregnancy increases energy needs by over  300 calories per day during the second trimester (over 400 calories per day in the third trimester) and breastfeeding by about 500 calories per day.[*][*

To be clear, these are just rough guidelines. A woman’s caloric needs will vary based on her age, weight, activity levels, genes, and a variety of other factors. The important thing is to eat more, not less. 

#2: Protein

Protein needs also go up. Pregnant women need about 15 extra grams per day, and nursing women need closer to 20 additional grams per day.[*][*

This means that pregnant and nursing women should focus on protein first in their macro strategy. The bare minimum is 60 grams per day, but 100 grams is a better target for active women.[*] High-protein foods like meat, fish, eggs and whey protein should be dietary staples, Keto or otherwise.  

#3: Micronutrients

Pregnant women, you might be aware, need more folate. Folate helps prevent neural tube defects in the fetus, and it’s why prenatal vitamins contain a big hit of folic acid. (Note: green leafy vegetables are excellent dietary sources of folate). 

To meet the increased vitamin and mineral needs during pregnancy, the United Nations Children’s Fund (UNICEF), United Nations University, and the WHO developed a multiple-micronutrient (MMN) tablet containing [*]:

  • Vitamin A
  • Vitamin D
  • Vitamin C
  • Vitamin E
  • Thiamin
  • Folate
  • Niacin
  • Riboflavin
  • Vitamin B6
  • Vitamin B12
  • Iron (during pregnancy only)
  • Copper
  • Iodine
  • Selenium
  • Zinc (increased dose for pregnancy) 

There’s also evidence that choline (from eggs and liver) and omega-3 fatty acids (from fish and fish oil) aid brain development in the growing fetus.[*][*] Pregnant women should strive to get enough of these nutrients too. 

Possible Benefits of Keto During Pregnancy

There isn’t much clinical evidence on Keto for pregnant or nursing women. We have anecdotal evidence, and we know that Keto can help other populations, but the jury is still out on this topic. Let's take a look at some potential benefits of Keto during pregnancy.

Avoiding refined sugar

If you want to maximize your health, it pays to minimize your intake of added sugar. Added sugar has been linked to most modern diseases—most notably obesity[*]—and maternal obesity may lead to bad outcomes for the fetus.[*]

Along with the Paleo diet, the Mediterranean diet, and a few other eating plans, a whole foods Keto diet is devoid of added sugar. This is undeniably good for both mother and child. 

Blood sugar control

About 1 in 6 births were impacted by women suffering high blood sugar levels during pregnancy.[*] High blood sugar triggered by pregnancy is called gestational diabetes. 

By limiting carbs, Keto restricts the foods that spike blood sugar the most. And the Keto diet, it’s been shown, can be an effective treatment for a similar metabolic disorder called type 2 diabetes.[*

The bottom line is that Keto may help with gestational diabetes, but more research is needed.[*

Risks of Keto During Pregnancy and Nursing

And here are some possible concerns about pre or postnatal Keto. 

Calorie restriction 

Undereating can stunt the growth of the fetus and impair Mom’s energy levels.[*

Since a Keto diet suppresses hunger, it increases the risk of accidental calorie restriction. Because of this, pregnant and nursing women should make a conscious effort to eat extra calories—especially protein calories—on Keto. 

Lactation ketoacidosis

Unfortunately, several case reports suggest that Keto can trigger a dangerous condition of elevated ketones called lactation ketoacidosis in a small percentage of women.[*][*][*

Why? Because milk production uses up lots of glucose, the body gets confused, and its ability to regulate ketone levels goes out the window. This doesn’t happen to everyone, but it’s something to watch out for. 

Fertility concerns

Some mouse data suggest that a ketogenic diet impairs fertility in the mother and slows fetal growth.[*][*] But this might not be applicable to humans because:

  1. Humans aren’t mice. We respond to ketogenic diets differently. 
  2. The mice were fed refined-mouse chow, high in inflammatory omega-6 fats.

Finally, a ketogenic diet has been shown to improve the sex hormone profile in women with PCOS.[*] So in some cases, this could be listed as a benefit. 

Tips for Keto During Pregnancy

If you want to try Keto during pregnancy, consider these tips:

  • Don’t be strict. Allow some carbs in your diet, especially if you’re breastfeeding. Lean towards the higher end of 10% carbs per day, and perhaps go higher. This is not the time to ruthlessly cut carbs and calories. 
  • Eat enough calories. Don’t stuff yourself like a starving hyena, but be careful not to starve yourself either. Track your meals with the Carb Manager app to confirm you’re eating enough on Keto.   
  • Limit the fasting. An overnight fast is fine, but anything longer than 12 or 13 hours may increase the risk of calorie restriction. Try intermittent fasting another time. 
  • Get enough protein. You’ll also want to track protein intake. Shoot for around 100 grams per day (maybe more if you’re active) to support pregnancy and breastfeeding. 
  • Nutrients, nutrients, nutrients. You need more of everything. Take a well-formulated prenatal multivitamin, supplement omega-3 fatty acids[*], and eat protein-rich, nutrient-dense foods like meat, fish, eggs and low-carb veggies. 

Is Keto Safe for Pregnancy and Nursing?

Scientists still aren’t sure how Keto affects pregnant and nursing women. Because of this, you should proceed cautiously. 

Along with following the above tips, work with your doctor to monitor your situation. If things start to look or feel off, consider bumping up your carbs by 50 to 100 grams per day. 

Many expecting women have flourished on low-carb diets, but everyone is different. Listen to your body (and your doctor) to set yourself up for a safe and healthy pregnancy. 

Comments 4

  • StellarCauliflower795152

    StellarCauliflower795152 11 days ago

    Thanks! I’m a breastfeeding momma and was so unsure if the keto diet was safe for me or my baby (since she’s drinking my milk!) What I gathered is that I can fast, just not over 12 hours. And I can also be on the keto diet- just tweak it a bit. Have at least 100g of protein, 10% or more of my diet be carbs, and don’t skimp on the calorie intake, but don’t overeat either. And drink lots of water, and add in electrolytes to avoid a deficiency.

    • Michelle_Chambers

      Michelle_Chambers 2 years ago

      I’m 8 weeks today and I wasn’t sure if I needed to adjust my carb intake!

      • nayaraevelyn

        nayaraevelyn 2 years ago

        Only a dietitian experienced in the Keto Diet will be able to tell. Regular blood testing might be necessary as well. Percentage wise, I didn't have to adjust anything. I ate more net cabs when my calorie intake went up at the second half of my first pregnancy. I'm 24 weeks with my second now and I don't see any reason to justify eating more carbs (other than pure cravings) - all tests just come out great! BTW, I don't do keto for weight loss so I'm not sure if what is valid for me would work for you.

    • cry154c514

      cry154c514 2 years ago

      Thank you!