Everybody is different, trail and error. Generally spices and things can upset bubs tummy but most people are okay

All the bad stuff like coffee, alcohol, drugs etc. Just remember whatever you eat, bub also eats. So avoid things that can cause issues in adults I’d consumed to excess

Lots of advice already ! Like others said alcohol, caffeine, medication/drugs and certain foods (cabbage, onion, capsicum, pepper, fish high in mercury, citrus fruits, etc) can affect your baby. Always watch your baby for reactions on foods that could be questionable and ask for medical advice if in doubt. As for chocolate, chocolate is a source of caffeine and can have the same effect as coffee and some mums found it has a laxative effect on baby….so again,observe your baby. If there is a history of peanut allergy in your family, make sure to avoid eating peanuts until after your baby is weaned. The allergenic compounds in peanuts and tree nuts can be transmitted through breast milk. If you’re not sure if your baby might have a peanut allergy, watch for wheezing, rash, or hives in your baby; these can be signs of an allergic reaction.
Parsley & Peppermint can reduce your supply (but small amounts should be ok).

As others have said, alcohol and caffeine should be limited. The only other thing to be mindful of is to be cautious of honey while breastfeeding. There’s a toxin (pyrrolizidine alkaloids) that can be in honey that comes from the bees pollinating a particular bush. The levels of this toxin are supposed to be limited in Australian honey’s however the allowable amount here in Australia is far higher than in Europe. While not an official guideline, it has been suggested by some scientists that breastfeeding mothers shouldn’t consume too much honey as a result.
There’s a good SBS link pertaining to this … http://www.sbs.com.au/topics/life/health/article/2016/01/22/can-too-much-honey-make-you-sick

alcohol is a no of course LOL but asparagus, onion and these kind of veges affected my son

Thankfully chocolate doesnt affect my bub! Things like medications, alcohol, caffeine can. My first cabbage would affect too.

You can have whatever you like, just be mindful that it all goes into the breastmilk. For example, I drank coffee – I would wait until after a feed and know that bub wouldn’t feed for another 3 hours so any caffeine would be minimal if any. Some people find that certain things upset bub – onion, garlic, dairy, wheat… eat a balanced diet and consider a food diary if bub is unsettled. Re alcohol – a standard drink takes one hour to be absorbed so will be present in your milk for that time. Just adding that in as some people need a drink sometimes

Try to avoid foods that can cause you to get gassy as bubs will get full of wind from it to… also foods that are too spicy.. its really a case of trial and error as i have found one thing that upsets one bubs tummy might not upset another bub..

I never had an issue with chocolate. But be mindful of foods with chilli and some beans can actually case bub to get a stomach ache. Sometimes you just need to see what your baby reacts to as all babies are different in terms of what foods they can tolerate.