Which nutrient is the most concentrated and provides calories needed for nerve functioning, insulation, and protection for body organs?

• A. Protein
• B. Carbohydrates
• C. Fat
• D. Vitamins

Answer: (C)

Fats are the nutrient that is most concentrated in calories, providing about 9 kcal per gram—more than double the energy per gram of carbohydrates or protein. That high energy density makes fats the main long-term energy reserve. They also support nerve functioning because the myelin sheath around nerves is rich in lipids, which fats supply. Fat provides insulation to help keep body temperature stable and cushions or protects internal organs from impact. Additionally, fats are needed to absorb fat-soluble vitamins A, D, E, and K, which require fat for proper uptake. Vitamins themselves don’t add meaningful calories. So fats best fit the description.