Imap command to fetch mailbox data in bulk

Question

I am using IMAP commands to fetch the mailbox data. Currently I am fetching mails one by one using mail id. But while reading large mailboxes its very slow.

IMAP Command:"$ UID FETCH uid body[]\r\n"

Is there any command or way out so that I can fetch bulk data using IMAP command?

Thank you;

Mayuresh.