Can a Low Carb Diet Impact Your Pregnancy?


If you are pregnant or planning to get pregnant soon, then you must have heard the general misconception about how women always gain weight during pregnancy and are never able to shed it off? This is wrong because women may or may not gain weight. However, the fear is so strong that they often think that a low carb diet is a solution to this.

Have you heard about the craze surrounding the ketogenic diet? It is the low carb, high fat diet. For those who stick to the strict keto diet protocol, weight loss becomes attainable rather quickly. The “quickly” part appeals to most, and encourages an almost extreme shift in dietary habits as those seeking weight loss chase the keto-zone.

Must Know Things About Low Carb Diet During Pregnancy

low carb diet

What is a keto diet?

A ketogenic diet is very low in carbohydrates and very high in fat content. Typically, 65-75% of your energy comes from fat, 15-20% from protein, and less than 5% from carbs. After ~3 days of a low carbohydrate keto diet (say <20g/day for those who track their macronutrient intake), your body will be in a carbohydrate-deficient state.

Your brain and central nervous system which depend on carbohydrates will require a different source of energy to function. This is where body fat and ketone bodies come into play. Your liver can convert body fat into ketone bodies, and use them as an alternate source of energy. This is why a ketogenic diet is linked with weight loss success stories. Essentially, you are starving yourself of carbohydrates, and your body compensates by accelerating fat burning.

It’s all about the ketones

The keto diet’s goal is to get your body to use ketones as the fuel. Ketones can be used for energy by different organs and tissues. This includes your heart, kidneys, and even muscles. What’s remarkable is that unlike fat, ketones can provide energy for your brain since they pass through the “blood-brain-barrier.”


The blood-brain-barrier is a protective filtering system in the vessels that carry blood to the brain and spinal cord, allowing only certain substances to enter. You can think of ketones as a reserve energy source that has evolved in times of starvation, since your body can rely on its stored fat.

What does a keto diet look like?

You basically have to cut everything that is a source of carbs, such as beans and legumes, grains products. Dairy products, fruits, starchy vegetables, added sugar (from transformed products). You essentially eat eggs, meat and fish, cheese and heavy cream, oils, nuts and seeds, avocados, low carb leafy greens. Needless to say that it makes eating a bit more complicated. And by limiting your food choices, you typically limit your food intake. That is why people tend to lose weight.

The thing is that a keto diet can lead to nutrient deficiencies as some many food groups are eliminated from the daily diet. You miss out on vitamins, minerals, antioxidants, and fibers (on top of constipation that is normal during pregnancy), all of which are important for baby and mother during pregnancy.

Pregnancy and weight gain

Pregnancy brings a miraculous transformation in women’s bodies, one that is accompanied by weight gainl. That is a delicate subject. You get to hear remarks like, ‘don’t gain too much. Gain enough. Not too fast. Lose weight before pregnancy, not during pregnancy’. Weight management during pregnancy is a tricky subject. Clearly there is a lot of pressure for women to “control” their weight. Not surprisingly then that it may be tempting for some to try a trendy new diet like the keto diet. But, the important question to consider is whether this is safe for you and your baby’s development during pregnancy. Managing your weight (during pregnancy or not) is not easy and comes with a lot of pressure.

Should you lose or store fat during pregnancy?

Early on in pregnancy, a mother’s body gears up to store fat, not burn it! Right away you can see how a ketogenic diet is conflicting. The placenta releases hormones like lactogen, prolactin, and progesterone which not only stimulate appetite, but favors the storage of fat. Whereas, in the second half of pregnancy, the placenta helps drive hormonal changes that favor the use of stored fat.

Specifically, the growing fetus uses carbohydrates, so mama relies on stored fat for energy. Pregnancy is not the time to lose fat, the evidence are clear on that one. Pregnancy is naturally driving mothers to store fat, to ensure adequate growth of your baby, healthy pregnancy and delivery, and successful lactation.


Will this low-carb, keto diet harm your baby?

Studies have shown that ketones can freely cross the placenta and be used by baby for energy. If that’s the case why is a ketogenic diet during pregnancy controversial? Because there is a difference between ketosis for 8 hours vs. Ketosis for months! Your body is smart. Under normal dietary conditions, it can juggle sources of energy quite well. Sleeping for 8 hours at night is essentially like fasting.

During that time, you are not consuming carbs, fats, and protein, because you are asleep! Your body still must function, so it uses fat stores for energy both directly, and to produce ketones to compensate for the lack of carbs. This is different than starving your body of carbohydrates intentionally for days on end, and attaining a ketosis state for months. To date, we don’t know the short and long term impacts of a maternal keto diet during pregnancy on the health of the mom and the baby. There is a difference between naturally occurring ketosis due to a good night sleep, and self-imposed ketosis due to dietary restriction. We don’t know if it is safe.

Can keto diet harm the baby’s development?

In short, the answer appears to be yes. Observational and experimental studies have shown that ketones pass the placenta, and are used by the growing brain of the fetus, impacting its functions. It remains unclear as to what are the short and long term effects of ketosis, and if there is a dose-response seen with the concentration of ketones in the mother’s blood. Therefore, to conclude, a low carb diet is not recommended during pregnancy as it could negatively impact you.

Please consult the doctor while setting your diet plan for pregnancy. It is necessary for both you and your baby.

Hope this article was of help to you! Please share your comments/queries/tips with us and help us create a world full of Happy, Healthy and Empowered Women!!