diff --git a/lisp/gnus/nnimap.el b/lisp/gnus/nnimap.el
index 7984998d21..1a1e13a23a 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -146,13 +146,16 @@ nnimap-request-articles-find-limit
   :version "24.4"
   :group 'nnimap)
 
+(defcustom nnimap-split-download-body nil
+  "If non-nil, splitting may also consider message bodies.
+This requires downloading the full message from the IMAP server
+during splitting, which may be slow."
+  :type 'boolean)
+
 (defvar nnimap-process nil)
 
 (defvar nnimap-status-string "")
 
-(defvar nnimap-split-download-body-default nil
-  "Internal variable with default value for `nnimap-split-download-body'.")
-
 (defvar nnimap-keepalive-timer nil)
 (defvar nnimap-process-buffers nil)
 
@@ -2100,7 +2103,7 @@ nnimap-fetch-inbox
 		 "BODY.PEEK"
 	       "RFC822.PEEK"))
 	    (cond
-	     (nnimap-split-download-body-default
+	     (nnimap-split-download-body
 	      "[]")
 	     ((nnimap-ver4-p)
 	      "[HEADER]")