Which of the following is a rich source of energy?

Among the macronutrients, lipids (fats) are the richest source of energy. While carbohydrates and proteins provide approximately 4 kilocalories (kcal) per gram, lipids provide 9 kcal per gram [t1][t2][t5]. This makes lipids more than twice as energy-dense as the other macronutrients [t1][t9]. Lipids serve as the primary source of stored energy in the human body and are essential for cellular structure and the absorption of fat-soluble vitamins [t4][t9]. Carbohydrates are the body's primary and quickest source of energy, but they do not match the caloric density of lipids [t4][t5]. Vitamins, on the other hand, are micronutrients that do not provide any measurable source of energy for the body [t2]. Therefore, in terms of energy concentration per unit mass, lipids are the most significant source [t9].

Sources

1. [1] https://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_29_02.html
2. [2] https://www.ncbi.nlm.nih.gov/books/NBK554545/