I fell into the group of almost instantaneous positive results, so much so, someone would be hard pressed into talking me into changing the course. I stumbled upon the health benefits and have reaped many in just 13 months. On the flip side of that, my son has started the carnivore diet three-four-five times. He drops 10-12-14 pounds in short order and then the "lack of variety" crunch happens. He and his wife like to eat out and they like to eat all kinds of food at all kinds of places. Maintaining the carnivore approach and eating at every restaurant within driving distance can't be a successful adventure. I told him if he ate carnivore 5-6 days a week and then ate out would be better than the SAD 7 days per week. But he opts out then opts in. My wife tried the diet, had OK results the first two weeks and then some significant weight loss the second two. She simply likes vegetables and fruits. Like me she came off the farm and meat and "potatoes" is a way of life. At some point she may be a candidate for keto type approach but for now, he plate could be heavy on the vegetables/fruits and lighter on the meats and she would be just fine. I think for a lot it is lack of patience. We live in a world where we want things right now, right here, in my hand this very minute. We have lost the ability to wait, lost the ability to work for something in the end and mostly just lost the art of patience. If a person does not see results the first week and then experiences some carni-keto type flu symptoms then it obvious the carnivore will not work for them. They bail. For most it is more than likely a combination of a lot of things. Scott