How much fat are you eating? Many of us find that much more fat and a bit more protien keep us from disappearing off the face of the earth. Also, Dr. D recommends moving the following foods to the O HB list: bananas, rice, buckwheat, almonds, monkfish, smelt, tuna, guava, mango, bluberries. Since I'm still allergic/intolerant to half of that list, I eat dark meat organic poultry - skin and all and mop up any extra oil with the white meat - and fattier cuts of red meat. (But not all the time.) After a year and a half, I still have no trouble with body fat.
I have a personal, totally uneducated theory about this: Perhaps those of us O's whose ancestors moved north to follow herds in the areas of the the receding ice age ate more protien and fat. The animals in those climates - sea mammals, cold water fish, caribou/reindeer(?), bear, etc. - are much more fatty than say, the gazelles and wildebeast of the African plains. So maybe northern Europeans do better on high fat than their African cousins?
Just something I've mused about as I desperately try to gain 10 - 15 lbs. back. Check out the Paleolithic Diet Page. Some anthropological studies say we ate tons of fat and had no signs of any of the modern "fat diseases" (which are really "starch diseases.")