Whole 30 is a paleo reset. You follow the plan for 30 days to reset your body from the effects of unhealthy eating, a bit like a detox. It is paleo but in a strict form, so no alcohol, additives, preservatives and concentrating on healthy nutritious food. Sugar is kept to a minimal ie only 2 pieces of fruit per day no juices etc. you eat 3 meals a day try to avoid snacks, no weighing or measuring your body in the 30 days. Also no logging of food just eat within the guidelines and include lots of good fats. It comes from the book "it starts with food" by Melissa and Dallas Hartwig. Their website is very helpful. It is strict but it really helps focus my mind and the last time I did it I had never felt healthier. I am not good at explains things so I hope I covered everything.
I am logging my food though old habits die hard.