Potato has a high GI which means it converts to sugar faster than wholemeal bread does. Therefore it will leave you feeling hungrier than if you had wholemeal bread. Both are fine, but if you want to stay feeling full for longer, oats are best! Eat oat cakes instead of bread for lunch. They are really low calorie and filling, and won't bloat you like wheat can. Same with rice cakes. I find that weight loss is guaranteed if you have carbs for lunch and no carbs for dinner- ie just protein and veg. Do this 3 times a week and you will def lose weight!