If you follow a meal plan, the app can work out what you need to buy. On the nutrition screen there’s Shopping list.
Choose a period. A week is usual; you can choose shorter or longer. The app goes through the days, collects everything in them and adds up identical products.
Recipes are broken down. If there’s a recipe in your plan, your list doesn’t say ‘overnight oats’ but the oats, the milk and the fruit that go into it -- in the amount that matches your portions. A shopping list with dish names on it is no use in a shop.
Ticking off. Tap a line as you walk round the shop.
Your swaps count. If you’ve swapped a dish for a day, the replacement dish is on the list and the original isn’t. If it weren’t, you’d buy the wrong thing.
What isn’t on it. What you eat outside your plan. The list follows the plan, not your diary.