it isnt calorie dense.
Rice is incredible calorie dense.
Put cooked rice in a blender with just enough water for it to blend, eat a few big bowls of this and be blown away by the incredible insulin surge, unlike any I have ever experienced from any other carb source.
Personally I find it scary how easy it is to reach 10.000 calories in a day, once you ignore your first sense of enough is enough, there is seemingly no limit. I try not to go there any more.
The most fattening food I enjoy is rice cakes dipped in peanut butter mixed with olive oil, eat this every night for a week and you will gain pounds of pure fat without any water or muscle gain, I tried it many times. The results are motivating.