Why do some people have smelly water and some people don't?

Every population stinks, but the degree of odor is different. This is related to personal diet and living habits, just like some people's breath is very smelly, which can kill people, only 2 years old; Some of them don't stink, and you kiss her/him with a faint smell of meat, which is the result of insisting on brushing your teeth every night and not eating too hot food.