Changing Start Weight: If you entered the wrong start weight during setup, open the Weigh-In screen, go to your start date, and update the weight to the correct number.
Changing Start Date: To set an earlier start date, go to that date in the calendar and enter your weight. The earliest weigh-in becomes your new start date.
To set a later start date or shift your start weight, use the Fresh Start tool under My Weight Goal & Plan > Weight & Calories. (On the website, it's under the Plan tab.)
Updating Your Plan: After adjusting your start weight or date, review your weight loss plan under My Weight Goal & Plan > Weight & Calories. You may want to update your target date or weight loss rate to keep your plan accurate.