Food and alcohol was my world and my identity …
If you believe that food and alcohol were really your ‘identity’ that’s pretty pathetic. Sounds like you needed a change, although preferably not the one you were faced with.
You can try telling people that you’re allergic to sugar and anything that changes into sugar in your body. Whatever you do, don’t mention the words ‘yeast’ or “Candida’ as these words seem to make people nervous for some reason.
As far as coping with being what feels like the only person on earth eating the way you do, I think this is something you just become accustomed to over time; I know I did