be honest with her and resist the passive-aggressive power play. tell her up-front that yes, you are still eating this way and that it's a change you plan to make for life. if you've yo-yo dieted in the past, she may have trouble believing you, but that is her issue, not yours.
tell her you have no wish to put her out and will bring a few dishes that everybody will enjoy. that's it.
As I ate the oysters with their strong taste of the sea and their faint metallic taste that the cold white wine washed away, leaving only the sea taste and the succulent texture, and as I drank their cold liquid from each shell and washed it down with the crisp taste of the wine, I lost the empty feeling and began to be happy and to make plans.
– Ernest Hemingway