With a sustainable lifestyle change based on sufficient exercise and a balanced diet, many chronic diseases (obesity, high blood pressure, diabetes, metabolic syndrome) can be alleviated, cured or their onset prevented.Those affected from chronic diseases find it difficult to change their lifestyle permanently. Intervention programs are often not geared towards sustainable behavioral change and take too little account of the individual's motivational factors.As a result, those affected revert to old patterns after a while.The applied research project "Sustainable Lifestyle Change", which is the subject of this book, deals with the question of how "sticking to" a healthy lifestyle can be supported from the perspective of motivational psychology and service orientation. This specialist book is aimed at people in the healthcare sector (health psychologists, doctors, nutritionists, etc.) as well as applied researchers and explains how affected people can be supportedin "sticking to" a healthy lifestyle.There are gaps in research and practice regarding this so-called maintenance phase of a healthy lifestyle, which this book closes: What measures successfully support those affected from chronic diseases in making sustainable lifestyle changes?What is the role of motivation and motivational orientation in maintaining a healthy lifestyle?What does the maintenance phase look like and what is the customer journey of those affected?What is the role of those affected and other stakeholders in the healthcare ecosystem in long-term lifestyle change?The findings are synthesized in a toolbox with recommendations for practitioners.