Part two of this series critically examines the elemental composition of human diets and their implications for body composition, metabolism, and evolutionary adaptation. It explores the roles of carbon, oxygen, and hydrogen in various dietary patterns, comparing carnivorous, Mediterranean, plant-based, and traditional English-American diets. The analysis highlights the significance of elemental ratios in metabolic processes, epigenetic mechanisms, and thermogenesis. It delves into the historical development of diagnostic techniques such as basal metabolic rate (BMR) and respiratory quotient (RQ), questioning their accuracy in diverse populations. Unique metabolic adaptations in Indigenous Australians are discussed, showcasing their exceptional thermoregulatory mechanisms and evolutionary responses to extreme climatic conditions. The paper also investigates the impact of environmental factors on human evolution, including the Ice Age's influence on dietary practices. Ultimately, it challenges conventional perspectives on human migration, evolution, and dietary recommendations.