A raw food diet is exactly what you all think it is....everything you eat is raw. The basis of this diet is that heat destroys the nutritients in everything we eat. There is protein on the menu, particularly fish, which is mainstream enough that many people have tried this diet. Most vegetables can be consumed raw, as well.
The drawbacks are you never get bread or rice, never a cookie...if it requires heat, you don't get it. I think what I'd find most dissatisfying is that you never get a hot meal. Never a bowl of soup on a rainy day.
This isn't meant to be a weight loss diet, it's more of a lifestyle change, like choosing only organic or 'green' food. It would be the next logical step if, after choosing only organic products, you wanted to get even more of the natural nutrients food offers.
There are restaurants in the city that cater to this diet. I'm sure if you do a google search you'll get more information.