Hi, thanks for using healthcare magic Phentermine and topiramate are both effective adjuncts for persons trying to lose weight. They can both affect taste. Phentermine can cause dry mouth or unpleasant taste and topiramate can cause reduced or altered taste. They decrease the appetite. In terms of treatment for the distorted taste you may want to increase your fluid intake (water) and use mint or gum. Reducing your portions is an effective way to lose weight. In low fat diets you would decrease your use of high fat foods (oil, butter, fatty meats, high fat milks , cheese or dressings) and increase the use of vegetables and fruits. In low carb you would increase the use of protein (eating as much as you wish), decrease the use of carbohydrates (bread/biscuits/pasta/rice/some cereals/potatoes) 13 pounds in 1 week seems like alot. Weight loss is good but if it is loss too too quickly, it increases the risk of gall stones. You may want to consult a bariatrican, weight loss doctor , for advice I hope this helps