Cellular metabolism is heavily influenced by dietary intake, which provides the substrates and energy needed for cellular functions. Macronutrients, including carbohydrates and fats, serve as primary energy sources, while proteins provide the amino acids necessary for tissue repair and enzyme synthesis. Micronutrients such as iron, magnesium, and B vitamins are cofactors in enzymatic reactions vital for cellular respiration and ATP production. Dietary choices also affect mitochondrial health, as the mitochondria are key to energy production and cellular metabolism. High-sugar diets, for instance, can lead to mitochondrial dysfunction and increased oxidative stress, while diets rich in antioxidants like vitamin E and polyphenols support mitochondrial efficiency. Emerging research is exploring how different dietary patterns, such as ketogenic or plant-based diets, influence cellular pathways, which could lead to tailored diets that enhance metabolic efficiency and longevity.