Clinical meaning
Clinical nutrition encompasses the assessment, planning, and delivery of adequate nutrients to maintain cellular function, support tissue repair, and meet metabolic demands during health and illness. Macronutrients are required in large quantities and serve distinct metabolic roles. Carbohydrates are the body's preferred energy source, yielding 4 kilocalories per gram. Simple carbohydrates (monosaccharides and disaccharides) are rapidly absorbed and can cause blood glucose spikes, while complex carbohydrates (polysaccharides including starch and fiber) are digested more slowly, providing sustained energy and promoting bowel regularity. The brain requires approximately 120 grams of glucose daily as its primary fuel. Proteins yield 4 kilocalories per gram and consist of amino acid chains that serve structural functions (muscle, connective tissue, enzymes, antibodies, transport proteins). Of the 20 amino acids, 9 are essential (must be obtained from diet). Complete proteins (meat, fish, dairy, eggs, soy) contain all essential amino acids, while incomplete proteins (most plant sources) must be combined to provide the full amino acid profile. Nitrogen balance is a key indicator of protein status: positive balance (anabolic state) occurs during growth and recovery, negative balance (catabolic...