Long lasting high blood sugar question

I have a question about what mechanisms could cause my blood sugar to do what I recently saw. I can't figure it out. Last night was my 40th birthday and I didn't stick with my diet (I had a chocolate cake for dessert - out with my kids, so I couldn't get drunk ;-) ). I figured it was a bad move so I decided to check my sugars an hour after I ate the cake (which was at the end of a Prime Rib dinner with a small green salad). At one hour my number was 166 and I was pretty relieved (I should mention that I have been diagnosed only with pre-diabetes at this point). As I usually do when I am higher than I want to be at 1 hour, I tested again at 1.5 hours. This time my number was 167. This was a bit disconcerting, but I tested again at 2 hours and it was still 167. By three hours I was at 166 again. I tested again before going to bed (almost, but not quite 4 hours after I ate the cake) and the numbers finally changed going down to 133. I figured things were headed back to normal and went to bed. However, I am very confused about HOW my sugars could stay constant for at least 3 hours after eating. I would have expected the number to spike and then start a descent (perhaps slow) back to fasting. I don't understand how my numbers could stay constant for so long at a number above fasting. The meter is brand new and hasn't given me any obvious errors. I should also mention that I have occasionally seen this in the past when I ate Chinese food (which I no longer eat since hanging around at 180 for hours after eating didn't seem like a good plan). Anyone else have this type of experience? What mechanism in the body would keep the sugars unmoving? Thanks!

A prime rib dinner will tend to have a lot of protein and a lot of fat which usually means that the things will digest more slowly and begin to hit your blood stream hours out. I'm Type 1 but will have the problem of a late and sticky spike when I eat a largish piece of salmon (which I now rarely eat).

Thanks. I think I understand. So the protein and fat in the prime rib was both a help and a hindrance in that it kept the full load of sugar from hitting my system at once and creating a giant spike, but also let the sugar enter my system over a very long period of time. This might help explain why my fasting BG was much higher this morning - I was still dealing with some of the food from the previous night.