Measuring ‘calorie efficiency’ tells us what percentage of the calories we feed an animal is converted into ‘eatable’ products for humans. These figures are quite shocking. For beef, it’s just 3%.16, 17, vii This means that for every 100 calories we feed a cow, we get just 3 calories of meat back in return; 97 calories are effectively wasted. For lamb, it’s around 4%. Better than cows, but still crushingly bad. Pork is almost 10%. For chicken, it’s 13%.
