Low Carbohydrate Diets During Lactation

What is the ketogenic, or low carb diet?

The ketogenic diet, also known as a low carb diet, is a weight loss strategy involving a diet that is high in fat, adequate in protein, and very low in carbohydrates. The diet avoids grains such as pasta, rice, bread, as well as sugars and fruit. By eating very few carbohydrates, the body is forced to break down body fat for energy, causing a rise in blood and urinary ketones. This can be an effective weight loss strategy for many people.

However, if the blood ketones become too high, the body’s blood pH becomes too low (acidotic), which is life threatening. This condition is called ketoacidosis, with symptoms including nausea, vomiting, abdominal pain, and diarrhea. Treatment includes hospitalization for intravenous fluids, carbohydrates, and correcting the acidosis and electrolyte imbalances.

The average non-breastfeeding mother on a low carb diet does not reach a high enough blood ketone level to become dangerously acidotic.

Is a low carb diet safe during lactation?

Lactating people are at higher risk for life threatening ketoacidosis as compared to non-lactating people because of their need to spend extra energy on making milk. If lactating people don’t consume sufficient carbohydrates, they will need to break down more fat for energy, causing higher blood ketones, as compared to women who are not lactating.

The risk of ketoacidosis increases among lactating people on low carb diets if they are ill with a virus or bacterial infection, or if they have extra energy needs such as heavy exercise, nursing multiple children, or donating extra milk. If you become ill while lactating and following a low carbohydrate diet, then consume carbohydrates and seek medical attention.

Overall, it is safest to avoid a STRICT low carbohydrate diet while lactating and to see a dietitian or their physician for further guidance.

Source: Current Developments in Nutrition 3(supplement 1) June 2019