I'm using longtable to break a table across multiple pages of my document. In HTML, I can do something like this to simplify the formatting of my table:
<table style="width: 100%">
<tr>
<td>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.</td>
<td>Ut enim ad minim veniam,</td>
<td>quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</td>
</tr>
</table>
This gives something that looks like this:

The column widths are automatically adjusted in proportion to the length of the text in each column, line breaks are permitted, and the width of the table is exactly the width of the page. How can I accomplish these three things with the longtable environment (or some other environment that allows tables to break across pages) in LaTeX?