Good for you, Eve, for reading the book! But after reading the book you should see that Primal will be difficult to follow without eating meat. When "Mark said you could do it," was that in an email directed to you specifically, or a general statement? I just don't think you can do a non-meat non-gall-bladder Primal diet without specialized help (I know I couldn't.)
Costahobo, those on starvation diets who turned skin and bones were thin to begin with. Larger people on starvation diets are still skin and bones and no muscle; they just have a lot of fat that the body doesn't know how to metabolize. Gary Taubes relates a story about a species of rat that is so programmed for fat retention, that they die of starvation even while they were still fat. While that's an extreme example, it pretty much blows CW out of the water.
Besides, it's no good to compare the 30's and 40's with now. It was only after World War II that food was abundant enough, and people sedentary enough, to gain weight consistently. But even hundreds of years ago, people could get fat on carbs. Look at all Old Master paintings that feature fat and busty innkeepers' wives. The women did incredible amounts of manual labor, so why were they still fat? They were probably genetically more carb sensitive than usual, lived on potatoes and bread.
The most meaningful comparison would be between 1958 June Cleaver and 1992 Roseanne Barr. June Cleaver had the same general appliances and exercise level that Roseanne did. Yet millions of June Cleavers were thin as a rail and millions of Roseanne Barrs are big. This also goes counter to CW. William Davis goes into more detail with his June Cleaver example in Wheat Belly
5'0" female, 44 years old. Started Primal October 31, 2011, at a skinny fat 111.5 lbs. Low weight: 99.5 lb on a fast. Gained back to 111 on sugar cheat. Currently fighting off sugar/candy cravings with bulletproof cocoa and a little rice.
I (try to) follow by-the-book primal as advocated by Mark Sisson, except for whey powder and a bit of cream. I advocate a two-month strict adjustment for newbies. But everybody is different and should tweak Primal to their own needs.