The only seemingly unhealthy vegetables are the ones containing a high pesticide load, and the ones we have genetically destroyed with our manufacturers. Here is a list of the vegetables containing the most pesticide load according to the Environmental Working Group. Although they are safe when grown organically, they can be terribly bad for you when tainted by pesticides.
LETTUCE : What could be so bad about lettuce!? Well, not too much, but it's also not good for you. Lettuce is basically just water, so it really does nothing for or against you. However, due to its bland taste, it's often paired with fatty dressings that are seriously bad for your nutrition.
Onions : Onions may seem like a healthy addition to your meal, but they really aren't doing too much good for you. They're also a huge magnet for bacteria, and should be heavily washed before use. In addition, onions are often paired with fatty foods like pizza and hamburgers.
Radishes : Although radishes are a pretty good source of Vitamin C, they aren't too high in other nutrients. In addition, large amounts have been known to irritate the digestive tract.
Sunchokes : The sunchokes, which is also called the Jerusalem artichoke, is a newly popular tuber that tastes like an artichoke. While it has some fiber and potassium, the benefits aren't worth it for the more easily-embarrassed diners. Jokingly called the fartichoke, these veggies can cause extreme gas.
Celery : Like lettuce, celery's bland taste and lack of nutrients lend it to be used with unhealthy dips and dressings. Also, eating too much celery has been found to be harmful due to toxins, and could lead to stomach pain.
Spinach : Like other veggies on this list, eating spinach regularly is actually a healthy practice, but consuming too much can have unhealthy reprecussions. Spinach contains oxalates that bind to iron and calcium to make them unavailable biologically. Overconsumption of spinach could also increase your risk of a kidney stone.
Bell Peppers : Bell peppers have great health benefits when grown organically, but unfortunately they are also very susceptible to carrying persticides. When shopping for them, be sure you read the labels and ensure that they were organically-grown.
Potatoes : Like bell peppers, potatoes are also particulary susceptible to retaining poisonous pesticides and chemicals. Potatoes are also often gentically modified by farmers, which is a controversial practice.
Tomatoes : Ketchup is a lot of high fructose syrup, and loaded with sugar, making this unhealthy. Here in the U.S.A., ketchup is used on nearly everything as a condiment. The ingredients consist of tomatoes, vinegar, sweetener, spices, and seasonings.
Veggie Chips : They are allegedly made with real vegetables which would initially seem to be a healthy alternative to potato chips. Two of the main ingredients are potatos, and corn, which is not much differen't from your every day potato chip. This stuff is actually cooked in canola oil which is said to be toxic to humans, and animals alike. Does not sound very appealing does it?
Spinach Dip : As it turns out chips are not all that is unhealthy! Heavy cream, mayo, cream cheese, and bread crumbs, make this healthy food unhealthy all together.