Interestingly, the calorie counts on food packaging are derived from the Atwater system (and later modifications) that estimate digestible calories from the amount of fat, protein and carbohydrates in each food item. These numbers are based on experimental research on food substitution and weight loss/gain done in the late 1800s and early 1900s. The calorie counts for alcohol are similarly based on the measurable amount of alcohol in each drink, except that the number used (7 kcal per g) was just a complete guess on Atwater’s part since they couldn’t do equivalent substitution experiments involving booze.
Interestingly, the calorie counts on food packaging are derived from the Atwater system (and later modifications) that estimate digestible calories from the amount of fat, protein and carbohydrates in each food item. These numbers are based on experimental research on food substitution and weight loss/gain done in the late 1800s and early 1900s. The calorie counts for alcohol are similarly based on the measurable amount of alcohol in each drink, except that the number used (7 kcal per g) was just a complete guess on Atwater’s part since they couldn’t do equivalent substitution experiments involving booze.