Earlier quoted context omitted.
He could have lost all that weight and still had bread, sugar, and potatoes but instead he gave up what he clearly enjoyed. Now he gets to live out the rest of his life fighting cravings, telling himself he's not allowed to enjoy food. How utterly sad.
Believe me, cutting out bread and sugar completely is 10x easier than some kind of lifelong moderation for a person that has struggled for it already for most of his life. And he is extremely happy with his new sugar and bread free life of increased mobility, less pain, and much lower blood pressure. At 64, he's learning how to ride a dirtbike and doing pretty well at it.
You're clearly an advocate for your father making healthy choices. So why would you advocate against the use of a drug that makes that easier?