I'm sorry that you had those health problems (after working so hard to be healthy). But IMO your doctor made the same mistake that most doctors make — they were and most of them still are confused about the roles that fat and carbs play in human health. It isn't carbs we need — it's fat . . . saturated animal fat and other healthy fats. Avoiding fat is hazardous for our health. The paleo people had the same type of lean, mean body that you were striving for. But they ate plenty of fat along with the protein they needed. Many armchair "experts" seem to think that wild animals are naturally lean. That's simply not true. Most of the prey species tend to get very fat (assuming that they have enough forage for good health).
In this country we did OK until the mid-1980s when Senator McGovern was assigned the task of deciding what healthy Americans should eat (for the USDA dietary guidelines), and unfortunately he listened to bad advice and inadvertently corrupted the guidelines, and the USDA has been stuck in the same misguided rut ever since. But that mistake marked the start of the worst decline in human health in thousands of years. Most of what we have been discussing here is covered in detail and in a much better organized fashion in chapters 7, 8, and 9 in the book.
Wheat today is nothing like it was 50 years ago...it's a completely different grain. And I believe that's why such a huge portion of the population is starting to get sick...and at such a frightening rate. Am I completely off base with this??
Kim, I have an advantage on you. You're "talking" with an old farmer here.

Believe it or not I was growing wheat 50 years ago (and I still live among the same fields on our farm today, where wheat is rotated with corn), and I can guarantee you that the difference between the wheat grown today and the wheat grown then is very slight. None of the nutritional values have changed significantly over the last century despite all the claims to the contrary made by armchair experts. And since gluten is protein, gluten content has not changed significantly either. So outside of yields per acre, the specs on wheat haven't actually changed enough to talk about.
But one thing that has changed that the "experts" seem to overlook is the way that wheat is processed for flour. Unlike 50 years ago, flours today are custom blended in order to increase the gluten content of certain types of flout to give them "better" baking qualities. People are eating more gluten because of the changes in flour, not because of changes in the wheat itself. And when I was a kid, wheat was a minor part of our diet. Pizza didn't even exist in the small towns near where I grew up. But by the 70s and 80s so much more of the stuff people were eating was loaded with gluten.
In general, the paleo people ate whatever they could trap or run down while hoping to not get run down and eaten themselves by a bigger or faster predator. But sometimes they had hard times, and they ate whatever they could find to survive on. And of course their diet depended on the area where they roamed, the weather, the seasons, luck, and their skills. But they preferred meat, whenever they could get it because meat is the only food that contains all the essential amino acids. Of course they didn't actually know that, but their body told them it was so. And they knew that meat and animal fat kept them healthy.
Tex