S.S.
First, remember that you had a wonderful epiphany-he did not. The fact that he has changed as much as he has shows exactly how much he loves and respects you!
Second, I went through something similar-one day I just wanted to do it all better-I make everything from whole foods and grow my own garden for fresher organic vegetables.
It was a hard transition for my (now ex) husband, even with his family history. I made a deal with him that he could keep one addiction-the stress it causes to be without it can actually be as bad for your health as smoking so let him have one. (some doctors have said stress is as bad as smoking) He chose Dr. Pepper.
Then I started making "healthy" junk food. I make whole wheat, apple sauce, oatmeal cookies or I use barley flour for chocolate chip cookies. I make whole wheat bread often, so he can eat it with butter and still be better than Jack in the Box.
It's all about getting better-add foods one step at a time. If you force him he will just hide it like he has and it will be so much worse than any compromise you have to make. Give him his space to do it his way and remember to encourage and praise him for his efforts rather than criticize for his failures-it will go a long way toward your relationship.
Don't forget exercise. Eating alone will not do it, exercise alone either. If he takes it off he can eat a little bit more and not be as bad off.
Good Luck.