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The Keto Diet While Pregnant (Is it safe?)

Is it safe to eat a keto diet while pregnant?

A strict ketogenic diet is not recommended during pregnancy. A low carbohydrate (keto) diet is designed to be catabolic (breaking down) as opposed to an anabolic (growth). The development of a fetus is a condition of anabolism.

Continuously restricting carbohydrates to ketogenic levels suppresses insulin levels too much for optimum fetus development.

This study on PubMed shows that consuming more than 75 grams per day of whole wheat bread during pregnancy improves the chances of not having a small for gestational age (SGA) newborn.

Is it OK to lose weight during pregnancy?

For an obese mother it is possible, but healthy fetus development should always be the priority. While body-weight will most likely not be reduced, body-fat could be lowered by eating a healthy, nutrient dense super-food pregnancy diet.

What can I eat to lose weight while pregnant?

Nutrient-dense foods such as wild-caught fish, organic, free-range eggs, grass-fed beef, fermented vegetables, fruit, keto-friendly nuts, dairy products (kefir), and legumes. Additionally, sprouted bread like Ezekiel bread, lentils, and milled flax seeds are helpful.

Can ketones hurt my baby?

No, moderate ketone levels will not harm your baby. Ketones pass freely across the placenta and can be used as a source of energy by the fetus.

In fact, this study points out that in the latter stages of pregnancy, ketogenesis at night is three times higher among pregnant women than among non-pregnant. It seems a pregnant woman is in ketosis and using ketones as energy in order to preserve the available glucose for the fetus.

Do I need to take vitamins when pregnant?

In addition to a healthy diet, a balanced prenatal vitamin is usually recommended. Look for the methyl-folate form of folic acid, it is more bioavailable than standard folic acid.

It’s also important to work with a certified pediatric nutritionist to formulate a comprehensive pregnancy diet. Vitamins shouldn’t be a substitute for healthy foods.

Proper nutrition is paramount while pregnant

Can you do a modified keto diet while pregnant?

Yes, by increasing your carbohydrate intake up to around 75 grams per day and eating more frequently. This should allow you to ingest the proper nutrition for healthy fetus development. Keto and pregnancy are still possible, you just won’t be in ketosis as long or as often.

In a clarification of the above-referenced study, all your carbohydrates don’t have to come from wheat bread, that’s just the carbohydrate they used for the study. In fact, some people are allergic to the gluten in wheat and people with Celiac Disease can’t digest it properly.

Can keto prevent gestational diabetes?

I researched and wrote an entire article on the subject you can access here: What’s the best gestational diabetes diet? The bottom line is the ketogenic diet can in a way prevent gestational diabetes. While you shouldn’t be on strict keto during pregnancy, if you follow a low carb diet before pregnancy you likely won’t be obese or insulin-resistant during pregnancy.

The best food to eat while pregnant will be foods that are low on the glycemic index and don’t spike blood sugar.

Foods to avoid while pregnant

Just because you can increase your carbohydrate intake doesn’t mean you can eat all the junk food you want. The same study that I referenced above that recommended 75 grams of carbohydrates from wheat bread also showed something alarming.

“Consuming industrial bakery products or pastries (refined sugar products) twice a week increased the odds of having a smaller than usual (SGA) infant.

National Institute of Health- PMC6471256

Here’s a good source for the dangers of simple sugars. It seems that refined sugar unhealthy for everyone from all walks of life. Other foods to avoid while pregnant are processed foods and unhealthy, vegetable oil, and seed oils.

When I explain the keto diet to newbies I always explain the difference between good fats and bad fats.

Here is a video that explains good oils and bad oil (fats)

Losing weight while pregnant

Just to reiterate the point I made earlier (it’s important). Losing weight while pregnant should not be your primary goal. If you’re overweight you can lower your body fat, but since the fetus is growing inside of you, your actual weight might even go up.

So when I talk about losing weight while pregnant, what I really mean is lowering fat while pregnant. There are two phases of pregnancy that affect fat storage.

During the initial stage of pregnancy your hormones will make it next to impossible to lose either fat or body weight, but that’s OK, it’s all part of the process.

“Much of the (pregnancy) weight gained is extra fluid (water) in the body. This is needed for things like the baby’s circulation, the placenta and the amniotic fluid.”

Pregnancy and birth: Weight gain in pregnancy – NCBI › books › NBK279575
Food choices are important during pregnancy

Keto and pregnancy: Eat complex carbohydrates

You’re not going to be in ketosis that often while eating a healthy pregnancy diet. However, eating complex carbohydrates (low glycemic) as opposed to simple sugars will still be helpful.

Complex carbs are digested gradually and don’t cause rapid blood sugar and insulin spike. Your body and fetus will still get all the glucose they need, but you won’t store as much fat. It will also be easier to lose excess weight post-pregnancy.

Here are some examples of some excellent pregnancy diet carbohydrates. Some support both keto and pregnancy:

  • Vegetables
  • Quinoa
  • Natto (non-GMO)
  • Avocado
  • Ezekiel bread
  • Nuts
  • Oats (steel cut, unsweetened)
  • Buckwheat
  • Fruit
  • Sweet Potatoes
  • Beets
  • Black beans
  • Chickpeas (garbanzo beans)
  • Lentils
  • Peas
  • Kidney beans
  • Black beans
  • Pinto beans
  • Navy beans
  • Pumpkin seeds, milled flax seeds, and chia seeds

What should be part of a good pregnancy diet?

We’ve talked about carbohydrates in-depth but the other two macro-nutrients also need to be discussed. Eat plenty of healthy fats for a good pregnancy diet. If you’ve been on a keto diet before you probably already understand the concept of healthy fats.

But I want to cover omega 3 fatty acids because they are essential for a good pregnancy diet. If you don’t get anything from this article about keto and pregnancy remember these five things:

  1. Eat more omega 3 fatty acids
  2. Consume fermented foods/drinks
  3. Eat green leafy vegetables
  4. Supplement with the methyl form of folic acid (folate) and B12
  5. See an obstetrician and pediatric nutritionist early and often
“Adequate consumption of omega-3 fatty acids is vitally important during pregnancy as they are critical building blocks of the fetal brain and retina.”

Add krill oil for a healthy pregnancy diet
Add krill oil to a modified keto diet while pregnant

Pregnancy Diet: We have to do better

I just read an alarming study out of New Zealand. Only 3 percent of pregnant women were meeting the nutritional guideline recommendations for all four food groups. The four food groups referenced were:

  • vegetables/fruit group
  • breads/cereals
  • milk/milk products
  • meat/eggs

Green leafy vegetables are some of the best foods to eat while pregnant

Adding omega 3 fatty acids to your diet will help you lose weight while pregnant. Fish is one of the best foods to eat while pregnant. However, it is important to choose wild-caught fish that are low in mercury. Here are some foods that are high in omega 3 fatty acids:

  • sardines
  • trout
  • salmon
  • mackerel
  • cod liver oil
  • algae oil
  • krill oil
  • chia seeds
  • hemp seeds. …
  • flaxseeds (ground)
  • walnuts

The three types of omega-3 fatty acids are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). We need all three types. Plant products like flaxseed contain ALA and fish products contain EPA and DHA.

A lot of pregnant women get uncontrollable cravings. Low carb peanut butter might be a good snack. You can read about the healthiest low carb peanut butter here.

“During pregnancy and breastfeeding, eating 8 to 12 ounces per week of fish and other seafood may improve your baby’s health.”

National Institutes of Health
Sardines are one of the best foods to eat while pregnant

What are the best foods to eat while pregnant?

Everything you put into your mouth also goes into the precious baby growing in your stomach. Everything you eat should be calculated and planned for optimum fetus health and development.

Keto and pregnancy might not be an ideal combination, but that doesn’t mean some of the healthiest keto superfoods shouldn’t still be consumed.

I recommend you read through this article: The Keto Diet Gold Standard Food list. Scroll down to the “gold standard” section and then add the previously mentioned complex carbohydrates to make up the core of your pregnancy diet.

Adding fermented foods to a pregnancy diet is essential

One way to continue a keto diet while pregnant (modified) is by adding fermented foods. Any fermented food is beneficial. Grass-fed, whole milk kefir and Natto are two of the best-fermented foods to eat while pregnant.

The fermentation process removes most of the sugar from whatever you are fermenting. This not only helps you lose weight while pregnant, but adds beneficial bacteria to your gut.

Milk kefir and natto (fermented soybeans) are singled out because they contain all three macronutrients: Protein, fat and carbohydrates. The whey protein in the kefir is extremely beneficial for the mother and the baby.

How to make kefir

Babies are born without an immune system and our immune system lives in our gut and intestinal bio-flora (gut microbiome). This study shows that the gut biome regulates the immune system. Beneficial bacteria are passed on from the mother to the infant.

Diversified gut microbiome health is important for both the mother and infant

One of the reasons keto and pregnancy might not be a good fit is because one of the dangers of the keto diet is keto constipation. The last thing you want to be is pregnant and constipated. Eating fermented foods can really help mitigate that problem, however.

Science is still emerging on the link to the microbiota and fetus development. However, the importance is increasing the more we learn. The microbiota-gut-brain axis is especially interesting. This abstract on Pubmed shows it may be a promising strategy for the treatment of autism in young children.


Doing the keto diet during pregnancy and losing weight while pregnant is not something that should be your primary goal. However, the primary benefit of keto is eating healthy fats and reducing sugar and starch consumption. This part of keto can still be safely followed…..even while pregnant.

Robert Bryant
Robert Bryant

This topic came up during my research of the gut microbiota and how the beneficial bacteria is passed from the mother to the infant. I wanted to share this information because I found it amazing that we could help our off-spring so much with just better food choices.

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