BBC News has seen documents, submitted to an Israeli Court, which give more detail than ever before about how and why Israel maintains its Gaza blockade.
In one document, Israel describes the import curbs as "a central pillar in the armed conflict with Hamas".
It also confirms estimates were made of how many calories Gazans need, but says these were not used for policy-making.
Israel says the blockade is to pressure Hamas, which does not recognise Israel and backs attacks on its citizens.
Three years ago, after the Islamist Hamas movement seized power, Israel and Egypt tightened their closure of Gaza's borders, leaving the territory's 1.5 million inhabitants facing acute shortages.
But Israel has never published a list of banned items, saying it approves requests on a case-by-case basis.
Items allowed have changed over time, which has left humanitarian organisation
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