Meal planning

You can pre-log. Not sure that's quite what you mean, but it's what a lot of people do. I already have my dinner for tomorrow logged (as it's Father's Day, I'm cooking my Dad a roast lunch) and, although the weights of everything won't be 100% accurate, they'll be close enough for me to be able to work backwards and see what'll fit with regards to breakfast and supper.

Or, you can save meals. If you do a regulr rotation of different breakfasts, for example, you could record each one as a meal, then copy it into your diary either in advance, or when you eat it.