I don't measure my veg carefully!
I have three good portions of veg and just get on with it! The veg are all from the allowed list so there is no problem there.
If I have spinach I don't count out the leaves - I buy it in blocks, chopped and frozen and I will do a couple of blocks in the microwave as one tablespoon of veg.
The poultry/fish needs to be weighed properly, though.