It's rubbish made up by formula companies. No mum can get that many naps a day and they know it full well, then when baby goes through a growth spurt she will think it's low supply caused by the lack of naps and their hope is a mother will feel it's her fault and start supplementing with formula. Some formula company websites, even here in the UK where we have strict laws about formula promotion even say similar things to what your doctor told you, even nowadays. I manage to sleep well at night while BF even if my sleep is broken up sometimes but as for daytime naps those are a rarity! Even when hubby is here I have an absolutely crazy almost three-year-old who even gives him the run around, so unless he is sleeping (rare these days) I cannot nap at all xx