I ate out and I have no idea what was in it. What do I do?

Tap Add food on your home screen, type what you had in your own words, and take a picture. A salmon sandwich on a gluten free bun with a side of french fries is a perfectly good entry. So is a 3 egg omelet with bacon and cheddar cheese. Something beats nothing. To list the ingredients, type each one under What is in it with how much.

On the same screen you can search your own recipes and ingredients and tap to add them, as many as you like, with an amount on each. Those carry real numbers and count toward your day. What you only describe in words does not, and your day's total says so.