What will happen if i don't eat any kind of bread for a month??

Depends...: Avoiding foods like breads, pastas and instead replacing them with fresh veggies usually leads to less stimulation of insulin and less calories. Ultimately, the idea is that this will decrease excess insulin (leading to fat production and causing damage that may lead to diabetes). If you have a gluten allergy (celiac), avoiding gluten altogether is imperative.

Maybe nothing: If a normal, healthy person decides to not eat any kind of bread, there is no problem as long as she gets all the necessary nutrients from other foods in her diet. Likewise, if she decides to eat no red meat, or if she decides to eat nothing that starts with the letter "P," or if she decides to eat no citrus fruits, etc... Life is about balance. As long as balance is maintained, life will be fine.

You can lose weight: certainly, eliminating carbs, breads in particular will help in weight reduction.