What foods should I avoid while breastfeeding?

What the evidence says

The good news is that breastfeeding parents generally do not need to avoid specific foods. The Canadian Paediatric Society is clear that there's no need to avoid milk, egg, peanut, or other common allergenic foods while breastfeeding, and doing so won't prevent allergies in your baby. They do advise against dieting while breastfeeding, since your body needs extra energy and nutrients to make milk.

A few things are worth limiting rather than fully avoiding. Caffeine passes into breast milk in small amounts; CDC notes this usually doesn't bother a baby at low to moderate intake, generally described as around 300 mg or less per day (roughly 2 to 3 cups of coffee), though some babies are more sensitive. High-mercury fish like shark, swordfish, and marlin should be limited because mercury can affect a baby's developing brain and nervous system, so choosing lower-mercury fish and seafood is recommended.

Alcohol is the one to be most careful with. It passes into breast milk, and MotherToBaby explains that waiting about 2 to 2.5 hours per standard drink before nursing again allows alcohol levels in milk to drop, though avoiding it altogether is the safest option, especially with a newborn.

Finally, standard food-safety advice still applies: steer clear of unpasteurized milk, cheese, or juice, and be careful with raw or undercooked meat and fish, since these can carry bacteria like listeria or salmonella that could make you unwell. If you ever notice your baby seems fussy, gassy, or has a rash after you eat something specific, it's reasonable to mention it to your doctor, but this isn't something to worry about proactively.