Bread and rice are both sources of carbohydrates. Once eaten and digested, they are both converted to sugar (or glucose) in the body. When eaten inappropriately, both of them can lead to weight gain and when eaten appropriately, either of them may result to weight loss.
Eating bread per se or simply switching from rice to bread will not cause anybody to lose weight. Weight loss will only result when the total number of calories consumed (regardless of the source of calories, whether carbohydrates, simple sugars, protein or fats) is less than the total amount of calories burned by the body.
Another important thing to remember is quantity. One half cup of rice is approximately equivalent to 2 slices of the “tasty” bread. So if you switch from ½ cup rice to 4 pcs of bread (without butter, mayonnaise or jam), you are consuming more calories. It is also worth mentioning that in making bread, oil or shortening and sugar are added. The oil used may contain trans fats or saturated fats which are not heart friendly and the sugar added, if a lot is not good for diabetics.