The total energy content in the potato = 84.0 Kcal
Amount of carbohydrate present in the potato = 20.0 g
Energy value of carbohydrate = 4 kcal/gram
Energy value of protein = 4 kcal/gram
Now the energy contribution from 20.0 g carbohydrate = 20.0 g * 4 kcal/1 g = 80.0 kcal
Therefore, the energy contribution from protein present in the potato is:
84 - 80 = 4.0 kcal
This energy corresponds to 1 g of protein
