I initially stopped eating fruit when I read Norm Robillard's theory of carbohydrates causing acid reflux in susceptible individuals. I found fruit to be the worst food for giving me acid reflux, and I've rarely touched it since. Anytime I have, I've almost always regretted it within 20 minutes. Non-starchy vegetables quickly became a much bigger part of my diet: they're low-carb and full of nutrients.
Am I missing anything by avoiding fruit? Lots of vitamin C and fiber? I made a chart to find out. Using Nutritiondata.com, I chose five fruits and five vegetables that I eat (or used to eat) and looked up how much of certain vitamins they contained. I chose vitamins that most of them had at least of little of. I also noted their total carb and fiber content.
(Click for larger image.) Note that the bottom lines are averages, not totals. (I never ate five cups of fruits or veg a day; I doubt many people do.) For vitamins A, C and K, the vegetables listed are the runaway winners. Vitamins A and K are fat soluble, meaning they have to be eaten with fat to be absorbed. How often do people eat the fruits listed with something that has fat in it? I know I didn't before going low-carb. I eat veg with salad dressing, butter, olive oil or ranch dip.
It looks like I'd get a little bit more folate and two more grams of fiber from the fruit--and a lot more carbohydrate--23 grams per cup, on average. The carbohydrate in fruit is mostly sugar. It may be natural, but it's still sugar. If you're concerned about blood glucose levels, weight gain, your teeth, and a variety of other health issues, sugar in anything but very modest amounts is bad news.