The regulation of energy balance and body weight is under the influence of complex neural, metabolic and genetic interactions. Despite this, obesity is now a global epidemic associated with significant morbidity and mortality in adults and ill health in children. Thus, the effective management of obesity has become an important clinical issue. To date, there are very few approaches to effective weight management in the long term. This book describes the main phytochemicals that have been suggested to affect homeostatic mechanisms and some non-homeostatic system that influence body weight.