It is important to try to stick to healthier carb sources like oats, rice, potatoes, sweet potatoes, fruits, etc.
But only this one higher carb day, if you start doing it more often than once per week then you’re not going to see much success on this plan.
If you must have a cheat meal and eat something unhealthy, then do it on this day.
Be aware that cheat meals or carb refeeds are NOT necessary, but they can up-regulate some fat burning hormones like leptin and thyroid hormones.
You will gain some weight during your re-feed day, but most of it will be water weight and you will lose it again in the next 1-2 days.