Eat the damn sandwich. Your success isn't so much contingent upon sticking to The Diet but in becoming optimally healthy. You would be healthier without the bread but you can be very healthy eating some bread. But the catch is that you have to actually learn about what is healthy instead of being a dieter who thinks that X diet is a magical zone of perfect health and all problems fixed. Study nutrition, exercise, and lifestyle and succeed whether you eat bread with your lunch or not.
Stabbing conventional wisdom in its face.
Anyone who wants to talk nutrition should PM me!