Understanding the energy content of food is essential for assessing the accuracy of nutrition facts labels. To enhance the precision of our calculations in this project, we focused on determining the energy derived from fat, carbohydrates, alcohol, and protein. We calculated the calories in a variety of beverages, including protein shakes, coffee, tea, sodas, juices, and alcohol. While the calorie counts for most of the 16 beverages increased, two beverages showed a decrease compared to their listed Nutrition Facts. These findings suggest that the calorie counts provided on the Nutrition Facts labels are generally accurate and mostly fall within the margin of error required by the FDA, which is about 20%.

To determine the total calorie content, we applied Atwater's system for calculating energy. According to this method, fat provides 9 calories per gram, alcohol provides 7 calories per gram, and both carbohydrates and protein provide 4 calories per gram. By multiplying the total grams of fat, alcohol, carbohydrates, and protein in each beverage by their respective caloric values, we were able to calculate the total calorie content for each beverage.