Food prep when hoping to BF

Have been prepping the freezer for birth but read an old post on here today saying not to prep anything with dairy/onion/legumes/brassicas if planning to breastfeed. Assume this is suggested to avoid upset baby belly but would you follow this advice and strictly prep meals which don’t include these things or eliminate things as you go along if finding baby is irritated? Have already made multiple meals containing all these things so reading this has me spinning because I don’t really know what else to prep!