Q.(a) Assume that you are a Dietician and a person who is very health conscious comes to you as a Client. How will you explain about the Calorific Value of Carbohydrates, Proteins and Fats? OR

Carbohydrates and Proteins each provide about 4 kcal of energy per gram, while Fats provide about 9 kcal per gram — more than double — a key fact for explaining calorie intake to a health-conscious client, answering part (a) of this either/or question.

This question offers a choice between (a) explaining the calorific value of carbohydrates, proteins and fats to a client, and (b) identifying a carbonic-anhydrase-catalysed reaction and its role. Since (a) can be answered fully on its own, it is addressed here.

As a dietician, the calorific value (the amount of energy released when a nutrient is oxidised/metabolised in the body) of the three main macronutrients would be explained as follows:

• Carbohydrates: yield approximately 4 kilocalories (kcal) of energy per gram. They are the body's primary and most readily used source of quick energy (broken down to glucose, used in cellular respiration).
• Proteins: also yield approximately 4 kilocalories (kcal) of energy per gram. However, proteins are primarily used by the body for building and repairing tissues, enzymes and hormones, and are used as an energy source mainly when carbohydrate and fat intake is insufficient.
• Fats (lipids): yield approximately 9 kilocalories (kcal) of energy per gram — more than double the energy density of carbohydrates or proteins. This makes fat the most energy-dense/concentrated nutrient, useful for long-term energy storage, but also means fatty foods contribute disproportionately more calories for the same weight of food. …