Dona is interested in cutting back on her calorie intake. Which nutrient offers the highest number of calories per gram?

1. Fat 2. Carbs 3. Protein 4. Vitamins

The correct answer will be option - Fats

Explanation:

The cellular respiration can produce energy from the three substrates: Carbohydrates, proteins and Fat, the most favoured of which is Carbohydrates.

The Carbohydrates on oxidation produces 4 calories per gram, proteins also produce 4 calories per gram whereas Fats produces 9 calories per gram.

The Fats produces the highest amount of energy as fats require more oxidation to release water and carbon dioxide as compared to Carbohydrates.

Since fats provide the highest amount of energy, therefore, option - fat is the correct answer.