Know What's Safe and What's Not
Nursing women should avoid undercooked foods or those that may contain bacteria, such as Listeria, due to poor cooking standards—but otherwise there are really no big no-nos once you're breastfeeding. Even sushi is OK if it's prepared up to healthy standards. (Watch for high mercury levels found in the raw tuna sashimi.)
Alcohol should be avoided as it can affect the milk-ejection reflex. According to a study published in The Journal of Clinical Endocrinology and Metabolism, alcohol disrupts the release of both lactation hormones, so infants ingest less milk from the breast following the mother's intake of alcohol. If you're going to have a drink, make sure that it is not right before a feeding or you may end up with an unhappy baby.
Breastfeeding has challenges of its own for every mother, but if you eat a properly balanced nursing diet and stay well hydrated, you should be well on your way to a successful nursing experience.