Energy Consumption: Food

People obtain the energy they have through the consumption of food. However, how much energy does it take to produce the food we are consuming?

Milk/dairy:
A typical dairy cow produces 16 litres of milk per day. If we assume that the average person drinks one pint of milk and uses 50g of cheese (equivilent to 450g of milk) for cooking, than each person needs 1/16 of a cow every day. Assuming a cow weighs 450 kg and has similar energy requirements as a person, it consumes about 21 kWh/day. So 1/16 of that means each person consumes about 1.5 kWh per day for dairy (McKay).

Eggs:
We will assume that a person eats an average of 2 eggs per day for breakfast. An egg-producing chicken eats about 110 g per day, which translates to 0.4 kWh per day if we assume the same ratio of energy to kg as people. If an average egg-laying chicken lays about 290 eggs per year, then eating the 2 eggs in the morning is equivilant to 1 kWh per day (McKay).

Meat:
In Hong Kong, the average person eats 365.2 kg of meat per day. Assuming that this meat is of equal amounts of chicken, pork, and beef, then each person is using about 13 lbs of chicken, 107 lbs of pork, and 268 lbs of beef. This is a total of about 280 kg of animal meat. If we multiply by our conversion of 3 kWh/day per 65 kg, this gives us a total of 12.8 kWh per day.

Farming and Fertilizer usage are negligible in Hong Kong, because less than 8% of the land area is used for farming. Hong Kong is essentially an entire city. So when we total the usage of all the food and farming kWh's, we get a total of about 16 kWh per day per person.