In the ever-evolving domain of nutrition science, an in-depth exploration of functional foods, nutraceuticals, and dietary supplements has emerged as a fundamental pillar for comprehending the nuanced interconnection between dietary choices and human health. This thorough investigation begins in Chapter 1, providing a broad overview of nutritional aspects of food. It delves into the complexities of nutritional value, the profiling of nutrients, and the crucial importance of food composition databases. The difficulties experienced in developing these databases, as well as the effects of ultra-processed foods on overall dietary quality, are examined, offering a comprehensive picture of the nutritional landscape. Chapter 2, offering a meticulous examination of the foundational concepts, including precise definitions, discernment of health benefits, and a comprehensive overview of the regulatory landscape governing functional foods, nutraceuticals, and dietary supplements. Serving as an intellectual prelude, this chapter establishes a conceptual framework to guide readers through subsequent sections. Chapter 3 further delves into the intricate world of bioactive compounds inherent in diverse foods. An exhaustive analysis dissects these compounds into nutrients and non-nutrients, followed by an elucidation of their specific bioactive properties. The chapter unfolds a detailed narrative, shedding light on the diverse roles these compounds play, ranging from antioxidants and cardioprotective agents to anti-carcinogens, prebiotics, anti-inflammatory agents, antimicrobials, and anti-ageing constituents. The inquiry progresses in Chapter 4, methodically unraveling the bioavailability of nutrients derived from food sources. A nuanced perspective on nutrient uptake is achieved through a sophisticated grasp of the factors impacting bioavailability, measurement techniques, and strategic approaches to enhance absorption. The interplay between intrinsic and extrinsic factors, coupled with innovative strategies such as food pairings, traditional food processing, and the integration of probiotics and fermented foods, forms the crux of this insightful chapter. Chapter 5 introduces readers to the intricate concept of glycemic index and glycemic load, meticulously detailing their implications for weight management, blood sugar regulation, cardiovascular health, and potential contributions to cancer prevention. Mechanistic insights into the metabolic advantages of low glycemic index foods are expounded upon, accompanied by an exploration of practical applications, challenges, and pertinent debates surrounding these indices. The pivotal role of dietary fibre takes centre stage in Chapter 6, where a comprehensive examination of its classification, physico-chemical properties, and diverse health benefits unfolds. From its impact on body mass index (BMI) to its substantial role in preventing chronic diseases such as cardiovascular conditions and colourectal carcinoma, this chapter sheds light on the multifaceted contributions of dietary fibre to overall health. Chapter 7 of the book chapter provide detailed exploration of the metabolomics field, covering fundamental principles, analytical methodologies, and quantitative analysis techniques. The chapter spans applications in biomedical research, emphasizing the role of metabolomics in understanding complex biological processes. In the context of food science, metabolomics plays a crucial role in ensuring safety, optimizing processing methods, and verifying food authenticity, including GMO identification. The chapter concludes by summarizing key insights and potentially suggesting future research directions. Overall, this comprehensive guide serves as a valuable resource for researchers, practitioners, and enthusiasts seeking an in-depth understanding of metabolomics and its diverse applications. Chapter 8 introduces the burgeoning field of foodomics, elucidating its foundational principles, challenges.