The 80 10 10 diet is about the only diet that I didn't try, at least for more than a few days.
Dr Graham doesn't really know what he is talking about regarding health in general, but I have to say he is right that fats and carbs don't mix well together. Actually this is the same for every food group, they don't mix well together.
If you must have an avocado, consume it at the end of the day, it is less likely to cause any problems. In a healthy individual, even a balance of 60-20-20 wouldn't cause issues.