The keto diet has been becoming increasingly popular over the past few years, and personally, I do use it with some of my clients who require rapid weight loss.  But, is ketosis safe during pregnancy?  In this blog, I’m going to provide you with an update on the research about low carbohydrate diets and pregnancy.

What is ketosis?

Just like a phone, animal or plant, our body’s need fuel to function. We get that fuel from food…. more specifically, usually from the carbohydrates in fuel. But, I’m sure that you’ve heard that as long as we still have water, we can survive for a few weeks without food.  When this happens, our body uses our fat stores for fuel in a process called ketosis.  ‘Ketosis’ literally means making energy from fat stores, and is a popular way to lose weight.

Now, current stats tell us that approximately half of all pregnant women are overweight when they conceive…. and this additional weight can lead to a range of pregnancy complications… so it stands to reason that you might be wondering whether a keto diet might be a healthy choice during pregnancy, especially if you’ve been diagnosed with gestational diabetes….

However, the current evidence suggests that ketosis is generally NOT safe during pregnancy.  Let me explain…

1. Pregnancy is a time when our nutritional requirements soar! 

When we cut out carbohydrate-containing foods, such as fruit, dairy products, starchy vegetables, legumes (like chick peas and lentils) and wholegrains… it can be more challenging to meet your pregnancy nutrition requirements.

2.  Fluid requirements sky-rocket during pregnancy

When our body is in ketosis, we lose fluid faster. You see, our liver and muscles store carbohydrates to provide our body with fuel during short-term fasts, like overnight. And, each gram of carbohydrate-stores, which are called glycogen, hang on to about 3 grams of fluid.  So, if our body has used up all these carbohydrate stores, it’s more difficult for our body to retain fluid – which is why you need to pee so much more often on a low carb diet.  Low fluid stores can increase your risk of pregnancy complications such as constipation and Urinary Tract Infections, which are already a big problem during pregnancy.

3. A lower carbohydrate diet doesn’t improve gestational diabetes 

Although you may be tempted to go on to a low carb diet if you develop gestational diabetes, a study of lower carbohydrate diets in women with gestational diabetes, found that it didn’t improve the number of women who needed to commence insulin injections.

4. Ketone bodies cross the placenta

Probably most importantly, ketone bodies which are produced when our body is in ketosis, cross our placenta. As our babies require a constant source of carbohydrates for growth and development, there are concerns about how these ketone bodies, and the lack of carbohydrates may impact the growth and development of your baby.

There is an exception… 

It’s important to note that a ketogenic diet can be one of the best treatments for some women with epilepsy.  So, it’s important that more research is done into this area. 

In 2017, research was undertaken on two pregnant women with epilepsy as they followed a ketogenic diet throughout their pregnancies. The first woman didn’t follow a true keto diet, but had a reduced carbohydrate diet, including approximately 75 grams of carbohydrate per day from fourteen weeks gestation.  She experienced a range of nutritional deficiencies, but had a healthy baby.  So, that’s good news! The second mum was on a keto diet prior to conceiving, and stayed on this diet throughout her pregnancy.  She delivered a healthy baby, but unfortunately the baby was born with physical deformities. 

I should also mention that there have been some animal studies conducted, and these have also found mixed results.  Some of the side effects of ketosis during pregnancy in these studies have included problems with brain development, physical deformities, nutritional deficiencies and behavioural issues in the offspring. 

Furthermore, preliminary research seems to suggest that ketosis is not recommended in the weeks leading up to conception either.

In summary: 

  • We need to remember that there’s not much research on whether or not ketosis is safe during pregnancy, and until more evidence comes out on how to manage it safely
  • It’s wise to cease your keto diet prior to conceiving, or as soon as you know that you’re pregnant, if at all possible.
  • If you have epilepsy, and really need to stay on a keto diet, make sure that you see a dietitian with expertise in this area. 

Now, if you would like help with a healthy diet during pregnancy, I’d love you to download my free pregnancy meal plan.  Just go to



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