To perform its daily physiological functions and maintain a constant internal temperature despite environmental fluctuations, the human body requires a steady supply of energy. Among the three main macronutrients—carbohydrates, proteins, and fats—carbohydrates are the body’s most efficient and readily available energy source. They typically provide about 45% of the total energy in developed nations and up to 85% in developing countries, reflecting their affordability and accessibility worldwide.
Carbohydrates are the most widely distributed organic compounds on Earth, forming the bulk of foods such as grains, legumes, fruits, and tubers. These foods are easy to cultivate, inexpensive, and provide nourishment to a large portion of the global population. Nutritionally, carbohydrates include sugars, starches, dextrins, and glycogen, each playing a unique role in metabolism and food quality.
Beyond nutrition, carbohydrates also influence the flavor, color, texture, and sweetness of foods. Their humectant (moisture-retaining) and plasticizing properties make them vital in food processing, preserving freshness and enhancing sensory appeal.
Nutritional guidelines generally recommend that carbohydrates should make up at least 55% of daily caloric intake, with proteins contributing 10–12% and fats less than 30%. Historically, human diets have contained 40–80% of total energy from carbohydrates. However, with rising income levels and the popularity of high-fat Western diets, carbohydrate consumption—especially from starch—has declined, raising health concerns such as obesity and cardiovascular disease.
Starch, the main digestible plant polysaccharide, remains the major carbohydrate in the human diet, primarily derived from cereals, rice, and potatoes. In the body, carbohydrates serve as the preferred fuel for the brain and nervous system, which rely heavily on glucose to function properly. Stable blood glucose levels are therefore crucial for mental performance, concentration, and overall well-being.
Chemically, carbohydrates consist of carbon, hydrogen, and oxygen—typically following the empirical formula Cn(H₂O)n. This structure inspired the term “carbohydrate,” meaning “hydrate of carbon.” Their solubility and reactivity stem from hydroxyl groups and carbonyl components, which contribute to their versatile biological roles.
In summary, carbohydrates are not only a primary energy source but also essential for maintaining health, supporting metabolism, and enhancing food quality—making them a cornerstone of the human diet.The Importance of Carbohydrates in Human Nutrition
