This is the carb cycle diet from Bill Phillips Anabolic Reference Guide (the original bible). Many bodybuilders over the years have used it. I have tried it with good success. 4 day cycle.
If you get the book it gives a great scientific explanation of why it works and break down days, meals, and ratios. It is a good read.

Day 1 - moderate carbs 1.5g/lb bw
moderate protein 1g/lb bw
low fat 1/4g/lb bw

Day 2 - low carbs .5g/lb bw
high protein 1.5g/lb bw
low fat 1/4g/lb bw

Day 3 - identical to Day 2

Day 4 - high carbs 2g/lb bw
moderate protein 1g/lb bw
low fat 1/4g/lb bw

Good luck, day 3 is rough, but day 4 makes up for it.