Click Meals per day or Categories per day in Renewal Settings to open "Customize meal categories for this plan". Choose Total Meals per day from the dropdown (only values that exist on the plan's price grid are offered) and, optionally, enter how many meals of each category should be picked per day. Leave all categories at 0 to allow any category. The category counts must add up exactly to the total or you get "Total meals per day must be the same as sum of all categories." The new days-per-week/meals-per-day combination must exist on the plan ("The Plan you are trying to set doesn't exist..."). Saving re-anchors the subscription to the matching plan price. The same modal exists per delivery date (How many meals of each type?) for one-off changes on a single day, but only while that day has no meals selected.