Atkins was a cardiologist, not a paediatrician. He was a world reknowned authority on ketosis as it applied to adults, especially those with health problems, but not on pregnancy or breastfeeding.

I'm assuming that as he never mentioned it in any of his books, he didn't know that a healthy breastfed baby spends its first six months in ketosis, until solids are introduced. He never quoted any figures from the World Health Organisation showing that women in famine and emergency situations, who are mal-nourished and almost certainly in ketosis, do breastfeed very successfully. Mortality rates for breastfed babies in these situations are almost the same as non-emergency rates for that country. They only increase when exclusive breastfeeding stops.

Knowledge has moved on. At the time Atkins was working, it was a general assumption that ketones might pass into breastmilk, but no-one actually checked if it did. It doesn't. I checked my own breastmilk at regular intervals, and I have since asked some of the leading authorities on breastfeeding in Ireland, who have access to all sorts of clinical studies.

Make your decision on whether or not you plan to be in ketosis while breastfeeding on current research, not an out-of-date radio interview.