Something that I do is make the meal of the day around the cultural dish instead of trying to change the dish itself. In Quito, where I am based, there are patients from many different backgrounds, including indigenous peoples, coastal families and highland traditions, and therefore, each of these groups has dishes that are associated with celebrations, religious observances and family identity. Trying to get someone to change how their grandmother prepared their food is requesting to remove their culture, and will not work in almost all situations.
So instead, I ask this one question at the start: "What is the food you could never give up?" Whatever that was, I kept that food intact and then designed the rest of the day around it.
For example, one of my patients was a female with type 2 diabetes who wanted to keep eating seco de pollo (a rich Ecuadorian chicken stew) that her family prepared every Sunday. Instead of eliminating it, I helped her prepare a meal high in fibre and reduced the amount of refined carbohydrates on Friday and Saturday, so by Sunday, her glucose level was able to accommodate eating the stew without excessively elevating it.