Way back in the 30's, a Doc by the name of Paul Kauchakoff did testing on the benefits of raw foods. He observed, that after eating a meal, a persons white blood cells would increase, indicating stress on the body, while eating a meal of raw foods did not elevate the count. He also discovered that foods that were altered also suppressed the immune system, indicating foods left in their natural state were assimilated into our systems much easier.
Many believe foods need to be cooked to kill bacteria and make it more digestible, but that's merely a learned behaviour. A few vegetables, as those in the cruciferous family, like broccoli, are a bit more difficult. But most foods do not become more digestible by cooking. Cooking foods actually create one more step in digestion, as the immune system needs to 'finish' the processing.
The best practice would be to eliminate processed, altered and cooked foods entirely from your diet . That includes milk, as it is both pasteurized and homogenized. It also means removing white sugar and flour as both are processed. For those finding difficulty in changing over, just begin by adding a small green salad to every meal, then slowly adding more veggies as your system begins to change. This works, as I was a great meat eater and even a sidesaddle look at a veggie ran close to wrinklin in my whiskersz. One of my Fav's was a 'Cold Cut Combo' at the local Subway. But after a while that Combo began to taste different. Finally, on a whim, I asked for it with no meats and it literally blew me away how much better it tasted. I'm a Veggie Sub guy now, and it still feels funny. Every once in a while I'll try my old meat combo, and its never equaled the veggie. It's important that you know that I didn't do that. My body actually changed my tastes for food. Switching gradually works.
Cooking also reduces the amount of bio-available vitamins and removes the antioxidants in the food. So you can double the amount of benefits available by eating raw.
There's hardly a week that goes by that we are not told of yet one more contaminant in another of our 'Processed foods'. Buying local, and eating organically grown raw veggies is a great step towards better health.