Carbs turn into sugar yes and it's distributed through your whole body. Just like you can't spot target a place to lose weight (you can't only lose weight from your stomach or thighs you lose it all over) you won't gain it all to one place either. everyone's body is different. having a sandwich every day isn't a bad thing as long as you watch your calories and get other food groups etc. try buying 100% whole wheat breads as you'll get more fiber and nutrition from it.
