Permaculture did not save them.

Cuba imported most of their calories in the form of grains mostly from the USA

go look at grain import data

I've seen this claim a couple times lately and can find very little to support it. Some of what I did find is below. I think maybe 2002 was their best year for local food production. Corrections are welcome.

In 2002, 1.5 MMT grain imported, 3 MMT sugar exported, 3.2 MMT food grown in urban gardens. That does not include their own beef, grain, and tropical fruit production and produce not grown in the urban farms and gardens. As far as calories the sugar they exported was 6 times as many calories in they imported in grain. That's in 2002, current numbers are quite a bit different.

I got the grain imports from here,
http://www.docstoc.com/docs/376498/Cuban-Market_-Good-for-US-Grain

The urban farms and gardens datapoint from here (its on quite a few sites),
http://www.organicconsumers.org/organic/cuba_organic_food.cfm

The datapoint on the 2002 sugar exports from here,
http://edis.ifas.ufl.edu/FE626