Changes can only be made for an entire week and not for individual days. Therefore, you can decide if you would like to have the changes start in the middle of your current week or the following week.
If you change the current week, it may be that Meals that you have already bought food for will disappear from your Plan and others will be displayed to you. For this reason, you should first think twice about whether you want to make the change for your current week or simply begin the following week. The change itself is usually displayed within 10 to 20 minutes after saving, regardless of the selected time period.