On a vegetarian low carb diet you DEFINITELY need a carb counter, because pretty much every food you eat is going to contain some carbohydrate. For our carnivore friends munching pure flesh this is less of a problem, but everyone wanting to follow Atkins or other low carb diet plans needs to monitor carbs carefully, especially in the earliest/induction phase of the diet.
The key to success, especially when you are starting out, is to ensure you count EVERYTHING! Those tiny half-grams here and there add up over a full day, and you don't want anything sabotaging your vegetarian weight loss success.
The carb counter below generates the net carbs in grams - this is an Atkins concept, based on the subtraction of dietary fibre which passes the system undigested from the less complex carbs that enter the bloodstream, because the fibre itself doesnt actuall get assimilated. It's important to note that food labelling systems are inconsistent around the world - eg in the UK, carb content usually includes the fibre total (which will be a lower number, and can be safely subtracted to calculate the 'net carbs' the food contains).
To be completely safe and consistent though... use this counter!
Whatever phase you are on, don't forget to check you are getting enough
vegetarian protein
in addition to your carb allowance. If you feel weak and crave more to eat, try a high-protein snack because this might well be what your body is looking for / trying to tell you.