I did Xndo with DH when DS was about 6months old. THey were OK with me feeding but rang to consult their dietician first. I could only have on shake a day and had to have extra calcium.
TBH it did work but my already established good supply suffered while I was on it. I stopped after a fortnight due to that.

A while after that I got back onto Calorie King and allowed myself 1800 cals per day. Far more successful and I didn't feel so wiped out I couldn't exercise.