Louis Armstrong was always rather stocky (not exactly fat but certainly never thin).
He did use laxitives a lot to control his weight, but he also loved food so all his life had trouble keeping his weight down.
Here is a picture of him when he was young and you can see he is very stocky and a little chubby
http://www.nndb.com/people/665/000030575/larms trong-med.jpg
And here is a picture of him when he was a lot older, and as you can see he is still carrying a few extra pounds
http://www.wilson-benesch.com/uploaded_images/ DR1009_Louis_ARMSTRONG_C-748281.JPG
btw VERY sad to hear this morning that Humph had passed on.