This review discusses the history and evolution of the state of dietary fiber (DF) with account of refinements in extraction methods and legal definitions subsequent to the launch of DF hypothesis. For a long time, defining and regulating DFs relied heavily on their chemical compositions and analytical methods. Although chemical compositions and analytical methods still play an important role in the definition of DF, physiological activity has also been taken into consideration. The precise definition of DF is still evolving, particularly whether oligosaccharides degrees of polymerization (DP) 3-9 should be considered as DF or not. Decades of scientific research have initiated the expansion of the term DF to include indigestible oligosaccharides with their DP between 3 and 9; hence responding to the positive health benefits of DF as well as fulfilling the needs in food labeling regulations.

The prevalence of overweight and obesity is on the rise around the world. Common comorbidities associated with obesity, particularly diabetes, hypertension, and heart disease have an impact on social and financial systems. Appropriate lifestyle and behavior interventions are still the crucial cornerstone to weight loss success, but maintaining such a healthy lifestyle is extremely challenging. Abundant natural materials have been explored for their obesity treatment potential and widely used to promote the development of anti-obesity products. The weight loss segment is one of the major contributors to the overall revenue of the dietary supplements market. In this review, the anti-obesity effects of different dietary or herbal products, and their active ingredients and mechanisms of action against obesity will be discussed.