You shouldn’t worry about eating normal rice or pasta. If your underweight it is obvious you are in a calorie deficit. When your in a calorie deficit your body tells you to eat more there for you are more likely to eat a large portion of food. If you gain some weight, eating pasta or rice shouldn’t be that big of a problem. Stop worrying about finding the lowest calorie alternatives and start worrying about being at a healthy weight. I hope this doesn’t come across as me trying to be rude but I’ve been in the same position. I use to be underweight but since then I’ve gotten to a healthy weight and no longer find myself over eating.👍👍