The purpose of this project is to use white-skinned sweet potato as the main material for weight control for overweight and obesity, the non-communicable diseases (cardiovascular diseases, cancers, chronic respiratory diseases and diabetes) are also included. All high quality sweet potato are provided by CAES in Taiwan to produce special nutrient food and health food that to do functional study in Shih Chien University and Taipei Medical University. In this study, the investigators will recruit overweight and obesity subjects that divide into white sweet potato group (experimental group) and no intervention group (control group) by using randomized, parallel and open clinical study in sixty days.