diff --git a/watch/inotify.go b/watch/inotify.go
index b4e6544..7cab0fd 100644
--- a/watch/inotify.go
+++ b/watch/inotify.go
@@ -107,6 +107,7 @@ func (fw *InotifyFileWatcher) ChangeEvents(t tomb.Tomb, fi os.FileInfo) *FileCha
 				}else{
 					changes.NotifyModified()
 				}
+				prevSize = fw.Size
 			}
 		}
 	}()
diff --git a/watch/polling.go b/watch/polling.go
index 773c82a..a5d8fb0 100644
--- a/watch/polling.go
+++ b/watch/polling.go
@@ -80,8 +80,10 @@ func (fw *PollingFileWatcher) ChangeEvents(t tomb.Tomb, origFi os.FileInfo) *Fil
 			fw.Size = fi.Size()
 			if prevSize > 0 && prevSize > fw.Size {
 				changes.NotifyTruncated()
+				prevSize = fw.Size
 				continue
 			}
+			prevSize = fw.Size
 
 			// File was appended to (changed)?
 			modTime := fi.ModTime()