An all fruit diet, or a fruit and veggie diet is actally very good for your body. That is, if you educate yourself well and eat fruits and vegetables that make up for the proteins, fats, and carbs that you won't be getting as much of.
As for those who say that you need protein - check out this site:
http://www.vegparadise.com/protein.html
Yes - fruits and vegetables contain fewer proteins than meats and nuts, but there are trace amounts of protein in everything. And with the fruit/veggie diet, you eat more than you normally would, so you can actually get close to or reach the suggested amount of protein you need in a day. To figure out how much protein you need, multiply your weight by .37 - this number is the amount in grams of protein that is reccomended for your daily intake.
And for those who tell you that you need carbohydrates - check out this site:
http://weightloss.about.com/cs/fruit/l/blc
arbfruits.htm
This is a list of the amount of carbohydrates (in grams) that are contained in various fruits. Fruits contain a lot of natural sugars. And they actually contain simple carbohydrates AND complex carbohydrates. Fruits that are packed with complex carbs include - apricots, oranges, plums, pears, grapefruits and prunes.
There are also several vegetables that are packed with complex carbohydrates. These include - broccoli, cauliflower, spinach, turnip greens, eggplant, potatoes, yams, corn, carrots, onions, all types of lettuce, celery, cucumbers, cabbage, artichokes and aspragus.
And as for fats, there are plenty of fruits that have natural fats. The only difference between the fats in fruits and the fats in other foods, is that these fats are actually good for your body.
Avocados contain about 4.5 g of fat (35 out of the 50 calories are from fat), nectarines and peaches are at about .5 grams (5 out of the 60 calories are from fat), and sweet corn contains about 2.5 grams (20 out of the 90 calories are from fat).
Because 35 out of the 50 calories that are in avocados are fats, it's important to limit yourself on eating this food. The fat is healthy for you, but it's still fat. Eating an access of it will cause your body to gain fat, which I'm sure is not your goal.
That's all of the nutritional value of fruits and vegetables that I hope your looking for, and this isn't including the natural vitamins and minerals that fruits and vegetables contain.
I highly reccomend this diet, although I don't reccomend the fruit only diet as a permanent lifestyle choice. The fruit only diet is specifically designed to detox your body of all the toxins that we consume on a daily basis. The fruit and vegetable diet would be much more appropriate for a permanent lifestyle choice. And feel free to moderate it according to your personal preference, as long as the other foods that you're consuming are healthy as well.
Those who are on an all fruit or a fruit/vegetable diet are reported to have more energy, less of a need for sleep, healthier skin complexions, and less overall percentage of body fat.
I hope this helped! Good luck (: