How to fix a food I just logged

Right after you log a food, its + shows a tick for about a second. Tap the row while the tick is showing and the food’s page opens for what you just logged. Change the amount, time or meal and tap Log, and it updates that entry instead of adding another.

Once the tick has gone, a logged food can’t be edited. Delete it and log it again with the right amount (see How to delete a food from your day).