Mature fish do not need more than one feeding each day, and one or two fast days each week is not a problem. Twice a day feedings is over feeding, and that also means double the organics load accumulating every day in the tank. Fry are different, they need more frequent feedings so they can develop properly.
Freeze dried foods are always causes of intestinal problems in fish--unless the food is first thoroughly soaked in water. Fed dry, it expands in the fish's stomach causing internal problems that do harm the fish long-term if not short-term. I stopped using FD foods years ago, there are safer and much more healthy foods anyway.
My schedule now is water changes on Sunday, with "treats" about two hours later (you need to give the fish time to settle to avoid other problems) being frozen daphnia and frozen bloodworms. Monday is a fast because they have eaten well the day before. Tuesday and Wednesday are prepared foods (flake, bugbites, pellet, sinking foods for substrate fish, whatever) fed once each day, in the early part of the "day" which means the period of tank lighting being on). Thursday is another fast day. Friday and Saturday, same as Tuesday/Wednesday.