Editing a recipe or custom food item does NOT change historical copies of the entry that have been logged in your food log. Instead, when you edit a recipe or custom food item, it only changes the recipe for future use in the food logger.
This means that if you log an entry, then later edit the corresponding recipe or custom food item, the historical entry in your food log will remain the same – like a “snapshot” of the way that entry was before you edited it. If you wish to update a previously logged entry, you will need to delete it, then relog it again after the base recipe or custom food item has been edited.
This is done intentionally. You can imagine a situation in which you frequently use a particular recipe or custom food item, then later edit it; if the app automatically updated existing entries, then it would potentially change months or years of past data, also invalidating past expenditure calculations. This method ensures that your past data is safe and cannot be changed by editing recipes and custom food items in the present.