diff --git a/Lib/imaplib.py b/Lib/imaplib.py
index 08e1520..129de06 100644
--- a/Lib/imaplib.py
+++ b/Lib/imaplib.py
@@ -1147,7 +1147,7 @@
         chunks = []
         read = 0
         while read < size:
-            data = self.sslobj.read(size-read)
+            data = self.sslobj.read(min(size-read, 16384))
             read += len(data)
             chunks.append(data)