diff --git a/src/gov/nist/javax/sip/header/SIPHeaderList.java b/src/gov/nist/javax/sip/header/SIPHeaderList.java
index 96843fea0..06413051e 100755
--- a/src/gov/nist/javax/sip/header/SIPHeaderList.java
+++ b/src/gov/nist/javax/sip/header/SIPHeaderList.java
@@ -502,9 +502,11 @@ protected StringBuilder encodeBody(StringBuilder buffer) {
         while (true) {
             SIPHeader sipHeader = (SIPHeader) iterator.next();
             if ( sipHeader == this ) throw new RuntimeException ("Unexpected circularity in SipHeaderList");
+            
+            //This determines if a null body was added https://github.com/usnistgov/jsip/issues/53
             int buffPosDelta = buffer.length();
             sipHeader.encodeBody(buffer);
-            buffPosDelta -= buffer.length();
+            buffPosDelta -= buffer.length(); // if 0 nothing was added to the buffer
             // if (body.equals("")) System.out.println("BODY == ");
             if (iterator.hasNext()) {
             	if(buffPosDelta != 0) {