I know hundreds of people who have spent years and thousands of dollars on tests looking for ulcers or spastic bowels. I tell them to lay off all dairy products for two weeks. The results are usually so striking that it changes their lives.
The most common type of meter in English poetry, in which there are five iambs (unstressed then stressed syllable pair) to a line: "But soft!/ What light/ through yon/der win/dow breaks?" (Romeo and Juliet).