Jason...

The 3 cups of veggies is only a guideline because it's assumed that you will be using some of the other allowed foods on induction that also contain carbs such as cheese, lemon juice, coffee and cream. If you aren't using those, you can surely fit in quite a few more veggies and still stay below 20 grams of carb. Don't just stick with lettuce, either; expand your horizons a bit and try some new veggies. You might be surprised at what you find that you like.