Is it safe to follow a ketogenic diet during pregnancy?

By Dr. Stephen Phinney and the Virta Team‍

This is an excellent question for which there is no solid scientific answer.  For medical/legal reasons, it is virtually impossible to get approval to do a prospective study of the safety and efficacy of a ketogenic diet for a pregnant woman and her unborn child.  There are numerous anecdotes of women who have purposefully conceived and carried a normal child to term on a ketogenic diet, and there is the historical cultural experience of aboriginal peoples who lived as hunters or herders (eg, Native Americans, Canadian First Nations, the Inuit, the Masai), who spent most of all of each year in ketosis.  But none of this qualifies as adequate evidence to endorse nutritional ketosis as an option during pregnancy.