If it is in hypothyroid that you are gaining weight, then certain foods have to be avoided like all kinds of cabbage family. Like cabbage, cauliflower, broccoli, brussel sprouts should be avoided. All kinds of millets like bajra, jowar, ragi, maize should be avoided. Certain oils like cannola oil which blocks the iodine should be avoided. All the oil labels should be checked that they should not contain soyabean as they they restrict the thyroid medicine. All soya products should be avoided or after 6 – 7 hours after taking the medication. You can limit the caffeine intake, 1 cup per day is allowed. Peanut butter or any butter should be avoided. Almonds or pine nuts, if you avoid, it is better, otherwise take them after 6 hours of taking medication. So stay healthy.