When you are creating a meal plan, you can either add new foods or add different options of similar foods, as substitutes.
To add an alternative option to that food you need to search for a food in the sections "Search food" and add it. After that, you need to click on the "+" sign next to that food description to add an alternative option.
You can also create food groups and list of equivalents. If you wish to know how check out this article "How to create lists of equivalents".
With this option you are giving your patients a balanced and diverse meal plan, allowing them to switch up food from meal to meal.