Yeah I thought about a delete/undo, but I figured that the only time anyone would undo is if they're just playing around with it at first. It used to be that when you tapped a food to add it, it would automatically do it, but instead I made it with checkboxes and an "log items" button so mistakes don't occur like that.

It's really up to you how often you update. The whole idea isn't to count precise amounts, just input the healthy portions of your meals and over time, hopefully, you'll see patterns of what nutrition your diet is lacking!