Although it may seem any vegetable would be healthy for you on a diet, there are vegetables high in carbohydrates and sugars. Stay away from corn, peas, cooked onions, pumpkins, acorn squash, butternut squash, potatoes, sweet potatoes. All of these options are either high in sugars or starches that will spike your blood sugar.
Also, stay away from fruits. Fruits may contain a natural sugar, but it is still sugar. Consider holding off on eating fruits until your diet is over.