From the evidence I've seen - high-fruit diets are generally not healthy. Fructose is becoming more obvious as not being a "healthy" form of sugar.
10 Reasons why Fructose is Bad
The Fructose Index is the new Glycemic Index
Fructose versus Glucose
Note that those articles are generally talking about fructose added to other foods - fruit is slightly better, given that it has vitamins, fiber, and is absorbed slower than, say, a soft drink. Still, eating excessive amounts of fruit will give you lots of fructose, which isn't recommended.
Check out the books/articles at another answer of mine for some recommendations for good food plans. They generally include both meat and vegetables (and fish, and eggs...)
Disclaimer: As you will find on any question of diet/nutrition (or exercise, or politics, or...) - there is no consensus, no "right" answer. (Nor am I a doctor or nutritionist, this post not to be taken internally).
For an opposing view of how great fruit is - see 30 Bananas a Day.