Based on the context and the answer, generate a question. 

Context: By presenting it and realizing the faults behind it all . Hopefully now I can avoid the sickening pains . I 'd end it off here , but i figured I better explain why onion , garlic and leek = bad for vegetarians , and why I do n't eat them : those three items above are designated to help with digestion .

Answer:

They have properties that cause bloating .



Why do garlic , leeks , and onions cause sickening pains ?