All vegetables vary in their caloric profile. Root vegetables are denser in calories than leafy greens. So when a coach adds mixed vegetables to your diet.. do not make it all about beets, carrots, corns or onions.
50g of wheat = 250g of raw potatoes roughly .. so you can see that Potatoes are to be counted more towards carbs allowance than veggie allowance.
To give you an idea about caloric profile of various veggies – see the picture and notice the calories per 100g