If for some reason you need to delete an entire day's worth of My Daily Log entries, there's an easy way to do so with just a couple of clicks.
Note: This process will delete ALL log data from the date selected. That includes food logs, exercise logs, and health data (blood glucose, ketones etc). There is no way to restore this date once it's been deleted.
In My Daily Log, use the left arrow (<) and right arrow (>) at the top of the screen to navigate to the date for which you'd like to delete data.
Scroll to the bottom of the screen, and select Delete, then confirm your choice.