These can cause your body to release extra insulin, which can cause additional weight gain. To lose weight, you must eat less. The only foods you should eat less of are those high in fat and calories. You should eat more of low fat, high fiber foods. Fat has twice as many calories as carbohydrates or proteins.
Wheat bread has more fiber.
It does if it's whole wheat bread. Make sure that whole wheat is high on the ingredient list. Some breads are actually just white bread with caramel coloring. Overweight is inherited. You may inherit a predisposition towards being overweight which will make you more vulnerable to obesity but still does not make it inevitable.