For those who are on low carb diets, I say eat as many carbs as you want on high carb day. Enjoy the day for what it is, a day to replenish your body and relax the mind. Some guys are taking in 800-1000 grams a day! Make sure to keep the protein moderate and fat as low as possible!. Do not overdue the protein there is no reason to. Its high carb day for a reason which is to spike insulin and replace glycogen.. On your 6 other days of the week especially if you are taking in 100 grams or less of carbs, these high carb days will be beneficial to your workouts and mental game. Keep the cardio in your routine and you should be completely fine. May have a little bloat and water retention but that is completely normal and will be gone in a couple days. Drink plenty of water so your body flushes it out! I recommend not even paying attention to the scale during this time. Repeat every 5-6 days and weigh yourself again near the end of the following week. To be assured all water retention has been eliminated and to get a more accurate weigh in. Personally my high carb days fall on Fridays or Saturdays so I always make sure to weigh myself very early on Friday mornings around 4 am. Every single week I hold water for a few days but its always eliminated by the time I weigh myself after a week of being back on low carbs of 100 grams a day or less. As most of you know on here, always weigh yourself first thing in the morning when you wake up, and without any clothing or jewelry such as watches.
Some guys even like to have two high carb days a week. Find out what works best for you. Only way to do that is to experiment and see for yourself.