The ketogenic diet, a very low-carb, high-fat diet flouts conventional nutritional advice. But there are good reasons for its popularity today. Being in a state of ketosis imparts many health benefits ranging from weight loss without counting calories to neurological and cardiovascular health benefits and lower risk factors of diseases including cancer. Ketosis, the state of fat-driven metabolism has been a normal process throughout human evolution. Ketosis enabled people to survive during famine and starvation.
Those who have been on the standard modern diet readily benefit from a low carbohydrate, real food, paleo diet and for certain patients, especially those with PCOS and insulin resistance, I recommend the Ketogenic diet to improve their fertility. I have repeatedly found that ketosis is actually beneficial for conception and for maintaining a pregnancy without complications. It is also conducive to the birth of a healthy baby.
While many women are following a ketogenic diet during their preconception period, the continuation of this diet during pregnancy has become a hotly debated, controversial topic.
Misconceptions about Ketosis During Pregnancy
When anyone talks about ketosis being unsafe in pregnancy, they are likely referencing studies on starvation ketosis or diabetic ketoacidosis (DKA) which are entirely different from nutritional ketosis.
|Nutritional Ketosis||Starvation Ketosis||Diabetic
|Blood glucose||normal||Normal or low||High|
|Blood ketones||Absent or trace||low||Very high|
|Blood pH||normal||acidic||Extremely acidic|
- Nutritional ketosis is a natural metabolic state in which the body is primarily using fat for energy instead of carbohydrates. Ketones in the blood are at healthy levels of 1-3mmol/L. Pregnant women often move into and out of nutritional ketosis and this is perfectly normal and preferably a beneficial state.
- Starvation ketosis happens when the maternal diet is depleted in nutrition and calories and the body is burning primarily stored fat for fuel.
- Diabetic ketoacidosis (DKA) is when ketones in the blood reach unhealthy, toxic levels of 10 mmol/L or above and blood sugar levels are 3 times the norm. It is a very dangerous metabolic state seen in people with diabetes where insulin or diet isn’t properly managed. Ketoacidosis should be avoided by all pregnant women. It is harmful to the brain development of the foetus.
Conventional wisdom still sees ketones as toxic metabolic by-products of metabolism and they are considered unsafe during pregnancy. Many experts are concerned with the presentation of ketones in a pregnant woman’s urine and regard it as dangerous as they presume ketones have potentially adverse effects on babies’ brain development. In fact, many experts believe inadequate carbohydrate intake can result in ketosis, which may harm foetal development. So they caution against a low carb, ketogenic diet during pregnancy and breastfeeding due to a lack of evidence regarding ketones effect on the foetus and newborn. People who discover they have ketones in their urine panic but it should be noted that, in pregnancy, urine ketones do not correlate with blood ketone levels and only blood ketone levels are clinically relevant.
Ketosis is the natural state during pregnancy
Not only is it natural but it appears that the state of pregnancy may favour ketosis. Research has looked at blood sugar levels in normal, healthy pregnant women and found that blood sugar levels consistently trend 20% lower than blood sugar in non-pregnant women. As part of the adaptation to pregnancy, there is a decrease in maternal blood glucose concentration, a development of insulin resistance and a tendency to develop ketosis. After overnight fasting, healthy pregnant women readily produce treble the amount of ketones compared to women who are not pregnant.
Maternal ketone body levels increase in gestation 2-3 fold from baseline and the relative insulin resistance also gradually increases with gestational time, resulting in susceptibility to a ketotic state.
Early pregnancy is an anabolic period with lower insulin resistance. This period is programmed to build maternal fat stores. When pregnant women are fasting unintentionally with morning sickness, they move into and out of nutritional ketosis temporarily.
Late pregnancy is a catabolic period with higher insulin resistance. This period is programmed to transfer nutrients to the foetus, including mobilizing maternal fat stores. Women are more prone to ketosis during this period.
Contrary to conventional wisdom, higher ketone levels are very beneficial for both mother and foetus. In late pregnancy, the maternal generation of ATP (energy molecule) comes exclusively from burning fat. Higher ketone levels are necessary to assist in brain development. The foetal brain derives 30% of its energy from ketones. After birth, healthy infants stay in ketosis for at least the first month of life.
It is completely safe for women to be eating a ketogenic diet during pregnancy. Women in ancient times were almost certainly ketotic during pregnancy. I recommend women start the diet at least two to three months before trying to conceive so that the mother is fat-adapted before becoming pregnant.