First Two Weeks in Ketosis

I'm taking in less than 50 grams of net carbs (carbs-fiber=net carbs) a day, as well as limiting protein consumption to less than about 150 grams a day, in order to force my body to run entirely on fat. I don't know of any ultra runners who restrict carbs to this extent so its going to be a great experiment.
My only concern is that the lack of cabs could effect my speed since fat requires tons of oxygen to be burned while carb can be burned without oxygen (anaerobically) during hard sessions. As someone who enjoys speedwork and shorter/faster racing, I don't want my diet to limit me.

You can see my recipes page to see what kind of things I've been eating.

Last Monday, on day four of my ketogenic diet I did a 20 mile trail run at Bear Creek Lake Park in Lakewood. The previous day -day three- had been rough, with moodiness, low energy, and a general feeling of fogginess. So going into the 20 miler I wasn't exactly excited, but I was hopeful: since I had been out of blood sugar for a couple days I should already be past "the wall." And it turned out great. There was a definite low point from miles 4 to 6, but it wasn't bad and when it passed I felt strong until I finished.

I'm not sure why, but the next day -day five- I slept until noon and woke up feeling like I hadn't slept in three days. The entire day was spent in a heavy fog, similar to a bad fever. After an easy run my energy was back enough to feel like I could make it through the rest of the day without passing out. Day six was slightly better but I still didn't feel very coherent until after some miles. Day seven brought 24.5 miles over two runs and I felt great for both of them.

On day eight I wrote "no more fog" in my running log and I felt like I was back. Day nine and ten were both above 20 miles each and no crash followed like after day four.

It's now day 13 and I can feel the affects of running 100 miles last week while also forcing my metabolism to undergo a major change. However, my running pace has quickened over the the last three days with no additional effort on my part and I think most of the fatigue I have is mental.

As a side-note, I think my brain operates better on ketones than on glucose: my attention span seems longer and I feel like I could read an entire book in one sitting -and actually retain 100% of it. I'm starting to feel like Bradley Cooper in Limitless. I need to do some research to find out if students anywhere have tried this.

The true test will come next month, when I race a 55'ish mile race, then an 8.6 miler the following weekend, then a 50k two weeks after that.