研究目的：本研究旨在瞭解影響成人減重成效之相關因素。研究方法：本研究為一橫斷式研究，運用PRECEDE模式中之『教育評估和生態評估』的階段，發展結構式問卷，並立意選取營養諮詢機構減重會員，進行資料收集，共回收116份有效問卷。研究結果：（1）研究對象三個月減重行為成效體重差平均值為5.25公斤（標準差2.42），體脂差平均值為3.39%（標準差1.67），腰圍差平均值為2.25英吋（標準差1.26）。（2）研究對象之減重行為成效會因性別、體型、減重行為信念、營養師社會支持之不同而有顯著相關。（3）許多因素都與成人減重成效有關，包含（a）前傾因素：性別、年齡、教育程度、體型、過去減重經驗、減重行為信念、減重行為自我效能，（b）增強因素：家人、同儕團體、營養師對減重行為的支持或反對，（c）使能因素：健康訊息來源、營養教育可利用性；這些決定因素可以解釋20.3%減重成效的變異量。結論：透過營養教育針對有效預測之變項設計個別化的專業飲食建議，強化健康體位與正確減重觀念，以建立體重控制之健康行為，進而提升減重成效。

Objective: This study aims to understand the factors that influence the effectiveness of adult weight loss behaviors. Methods: This study is a cross-sectional study that uses the stage of ＂Education Assessment and Ecological Assessment＂ in the PRECEDE model to develop a structured questionnaire, and deliberately selects the weight loss members of nutrition consulting organizations to collect data. A total of 116 valid questionnaires were collected. Results: (1) The average weight difference of the subjects weight loss within three months was 5.25 kg (standard deviation 2.42), the average body fat difference was 3.39% (standard deviation 1.67), and the average waist circumference was 2.25 inches (standard deviation 1.26). (2) The effectiveness of weight loss behaviors of the participants was significantly related to gender, body type, weight loss behavior beliefs, and nutritionist social support. (3) Many factors are related to the effectiveness of adult weight loss behavior, including (a) Predisposing factors: gender, age, education level, body type, past weight loss experience, belief in weight loss behavior, weight loss behavior self-efficacy, (b) Reinforcing factors: support or opposition to family behaviors by family members, peer groups, dietitians, (c) Enabling factors: sources of health information, availability of nutrition education. These determinants can explain 20.3 % of variation of the weight loss effectiveness. Conclusion: Through nutrition education, individual dietary advice on effective predictions is designed to strengthen the concept of healthy body position and correct weight loss, so as to establish healthy behaviors of weight control, thereby enhancing the effectiveness of weight loss behavior.