h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Udon noodles in any type of soup base take essentially only as long as it takes to boil the soup base, and you can add almost anything to the soup which is formed after that.

One of my personal favourites (for one) uses a cup of vegetable stock, heated with a cube of frozen spinach - which in the time it takes the stock to start simmering will melt down into a swirling mess of spinach. When the mixture is simmering, add the Udon noodles and heat on simmer for the (usually with packet Udon noodles) recommended three minutes or so. For variety, you can add chopped eschallots or other bits of greenery, should you want them, and serve with a dash of soy sauce.

The soup so formed is nutritious for all relevant nutrients except protein, of which it doesn't have much. Given the protein - more particularly fat - most people ingest as part of a regular Western diet during the day, however, this is unlikely to do the 'eating body' any damage!

It's good, tasty food, quick to prepare as long as all the ingredients - all of the essentials of which can be stored for long periods - are available, and quite filling.