Food does not cause pimples. Not even chocolate nor fried food causes pimples. This sebum plugs up the skin pores and causes irritation and pimples. Most people do not get the amount of vegetables they need. Fresh vegetables usually are low in calories, fat, protein, and sodium.
Fresh vegetables are usually high in vitamins, minerals, and fiber.
The Food Guide Pyramid recommends 3-5 servings daily. Dark colorful vegetables usually have the highest nutrient value. I suppose someone can eat a large amount of vegetables. Maybe even too large. One person I know loved carrots, ate lots of them daily, and her hands turned slightly orange.