Personally, I think that raw food ideology is based on some serious misconceptions. The idea that plants actually contain the enzymes necessary for their own digestion doesn't make sense in an evolutionary context. Most plants, with the exception of fruit, do not want to be eaten. It in no way serves the biological purposes of the plant to provide for its own digestion. Any plant that did substantially provide for its own digestion would quickly be eliminated because it becomes such an attractive food source for any animal. The reality is that most plants actively discourage you from eating them, especially in their raw form. Sometimes this means a toxin that gives you an upset stomach, locks up nutrients, or in the most extreme cases kills you. Plants would not evolve mechanisms for their own digestion. Nature would select for plants with the strongest defenses against being eaten.
Now it is true that humans have been selectively breeding for some time and plants have been getting more edible but they are still a far cry from actively supporting digestion. This whole idea really smells of Mother Nature worship like the world was built with everything we could ever need(Fruitarian logic and pretty much total bullshit).
As far as your reference to the speed of digestion, I would suggest to you that just because something passes quickly does not mean its being digested efficiently. My hypothesis would be that raw food is relatively indigestible, and your body has very little use for it. Therefore it is excreted as quickly as possible. My advice to anyone who makes vegetables a regular part of their diet is to cook the living hell out of them. Breaking down the fiber as much as possible, and eliminating as much of the plants own enzymes as possible should ensure better access to the basic nutrients in plants.
I am highly skeptical about the biophoton idea, again because it based largely on fake science. Organisms do not "store" light energy. Producers like plant use light energy as a catalyst for building sugars. Herbivores can convert these sugars into animal biomass, and carnivores can convert animal biomass into more biomass(although usually less than the herbivores). Sugars are the basis of most plant energy and structure. Foods with the highest "light energy" content would simply be the ones with the most sugar, fat, protein, calories, or whatever name you'd like to call them. If your looking to eat the most "light energy" you'd simply have to eat the most energy dense foods.
Overall, I'd say that cooking food is perhaps the most important technique developed in human history because in most foods it makes nutrients more bioavailable than was ever previously possible. (at least to humans, WE ARE NOT HERBIVORES).
I wanted to add, digestion one of the most intensive processes your body undertakes. We sacrifice a fair amount of energy and nutrients in the hopes of obtaining even more from the food but this is not always the case. Ensuring that you get the most basic nutrients out of your food really takes a lot of pressure off of your body. In my opinion, cooking is basically predigestion and greatly eases the stress of actual digestion.