05-14-2016 19:38
05-14-2016 19:38
05-14-2016 23:33
05-14-2016 23:33
You can't delete all the data from yesterday but this article explains how you can delete some of it:
http://help.fitbit.com/articles/en_US/Help_article/1306/
It's an unusual question. Is there any reason why you are wanting to do this?