There are encouraging prospects to improve animal and human health through focused dietary approaches at the nexus of functional food production and livestock nutrition. In order to support the contemporary idea that “you are what your animals eat,” this chapter examines how feed composition has a substantial impact on the nutritional and functional quality of products derived from animals. In livestock, functional nutrition entails creating diets that yield value-added products like meat with enhanced lipid profiles and antioxidant capacity, eggs fortified with vitamins, selenium, DHA, and lutein, and milk enhanced with omega-3 fatty acids and conjugated linoleic acid (CLA). Nutrigenomics further supports these efforts by elucidating gene-nutrient interactions that drive the expression of health-related traits. Probiotics, prebiotics, synbiotics, essential oils, functional fatty acids, and organic trace minerals are examples of feed additives that improve nutrient bioavailability, immune modulation, and product quality. Case studies demonstrate the popularity of functional foods that appeal to health-conscious consumers, such as designer milk, omega-3-enriched poultry products, and grass-fed beef. Legal frameworks in the United States and the EU are changing to control functional food claims and labeling as consumer demand for clean-label and fortified animal products rises. Circular feeding with agro-industrial by-products, insect meal, algae, and seaweed are examples of sustainable nutrition techniques that provide eco-friendly answers that meet contemporary ethical standards. Forward-looking innovations like personalized nutrition and precision livestock feeding will enable real-time diet optimization based on market preferences and individual animal needs, placing livestock nutrition at the forefront of creating animal-sourced foods that are more sustainable, ethically sound, and healthier.