There are two things one can actually survive on long term if they have to worldwide

The most pleasant one is actually Organic Baked Potatoes. 

However, if you are ONLY eating Organic Baked Potatoes you MUST eat the peelings in order to do this because the peelings are where most of the nutrients are.

The pleasant one going in but not so pleasant going out is coconuts.

However, to survive on this diet of "ONLY COCONUTS" you have to eat coconuts directly off trees where they are growing because you MUST eat them at every stage from the stage where they are ONLY Coconut water to the stage where the white part gets hard and everywhere in between.

But, like I said coconuts might taste good going in but likely would give you the runs on their way out of you too. However, if you drink Coconut milk at the early stages you might not have to find a water source either because often coconut palms grow right along the ocean.

For those of you trying to survive worldwide during these times this is all good to know how to survive almost anything if you can either grow enough potatoes or you live where coconuts grow.