What is the approximate energy content per 100 g of protein?

• A. 1600 kJ
• B. 1700 kJ
• C. 3700 kJ
• D. 1000 kJ

Answer: (B)

Protein provides about 17 kilojoules of energy for every gram metabolized. So for 100 grams of protein, the energy content is roughly 100 × 17 ≈ 1700 kilojoules. This 17 kJ/g figure is the standard estimate used in SEHS for protein energy (some rounding to 16–17 kJ/g due to small variations in digestibility). The other options don’t fit because they reflect different energy densities: fat supplies about 37 kJ/g (≈3700 kJ for 100 g), while 1600 or 1000 kJ would correspond to 16 or 10 kJ per gram, which aren’t the typical energy values for protein.