The vegan chef's name is Julienne - he has a raw food cookbook that actually has beautiful recipes and instructions for dehydrating...
Health reason behind this concept of eating 'raw' organic matter is providing your body with optium nutrients that are killed when food is heated above 110 degrees, rendering it 'dead'.That's why eating things like sprouted seeds and beans are so important - they're alive.
There is a place called The Optimum Health Institute located in Lemon Grove Ca, just outside of San Diego.They have a program of fasting and eating raw, to detoxify the body as well as the mind.You can book a stay from 1 to 3 weeks depending on your health needs, and they teach you how to prepare and 'cook' raw, along with the concept of food combining, so you can continue
your program in the real world. Many of the people who go there have serious health issues- cancer or immune deficiency - have seen marked improvement/remission from this lifestyle.
As a chef, I occasionally suffer from food 'burnout' and go stay at the institute for a week. Eating raw and fasting not only detoxifys my system, but I can really TASTE food again. You'e got to detox to retox!
Peace.