In my experience, if I've been in sugar burning mode, which is what most every American and probably person in the world is in, the results of the experiment hold mostly true.
However, if I am in fat burning mode, or Ketosis, which I try to stay in all the time now, these results of this experiment are inconsistent with my experience.
When your body is running on glucose, you're very sugar sensitive because it's not healthy for your body to have high blood sugar at any given time, so it gets rid of it, and your body doesn't make glucose, so it's dependent on recently consumed fuel. But if your body is running on ketones, it doesn't just get depleted, it continues to turn fat into ketones and your brain doesn't ever feel the imminent need for more fuel.