Welcome Dixie Girl!!!!!
My suggestion would be to list all your foods on fitday.com. It allows you to see what your carb and calorie intake are, as well as going to the reports section to see if you are getting the proper nutrients.
I can't imagine that lettuce could cause a problem with weight gain. Some of the more experienced people here suggest you start a journal and list your foods.....that way, they can analyze and see if there is a problem.
I wish you lots of luck.....this is a great way of eating.
Remember, drink your water......LOTS of it!!
Kay