Dainty dogs may have to eat dirty puddings.

Someone with exacting tastes may find that necessity leaves no room to be choosy. Even an unappealing option can become the only practical one.

The proverb gently undercuts fastidiousness: preferences matter less when circumstances change and a person must make do with what is available.

Use it when a choosy person has to accept food, work, or another option they would normally reject. It can sound teasing, so take care if the person's circumstances are difficult.