Excellent is the idea of aiea7 to exempt not only food but also healthcare and other items purchased by the poor.  
The Democrat controlled legislature has been neglecting the plight of the poor by refusing to grant exemption to the excise tax on food and healthcare purchases by the poor.
However, in 2009, under the administration of Governor Linda Lingle,   a refundable food/excise tax credit was submitted to the Hawaii Legislature and enacted into law.
The refundable food/excise credit was increased this year.
The thing here is that to get a refund on food purchases, the poor has to file an income tax return.
And that may be a problem because most of the poor (including the homeless) may not be filing an income tax return and so be unable to get a refund.