I have found (although still fairly new to all this) that allowing yourself a "treat" not a "being naughty or bad" gives you permission to eat a little something now and then. The secret is to then say, that was lovely and i will treat myself again next month/week... little goals help me to...
I am wondering if his personality has changed? My reason for asking is that i have heard that some drugs used can make changes and that it might explain his attitude. Not sure if this helps but if it is having an affect then maybe you could try a different approach to consider seeing his doctor?