Caloric content of fast-foods.

CALORIC CONTENT OF FAST-FOODS. Chris Hornbuckle, Livia Cara, Trisha Mantooth, and Alfred Nichols, Department of Physical and Earth Sciences, Jacksonville State University, Jacksonville, AL 36265.

The caloric yields from the complete oxidation of fats, carbohydrates and proteins are about 9 kcal/g, 4 kcal/g and 4 kcal/g respectively (Berg et al., 2007). However, this information is often difficult to use in making fast-food selections. Such food products generally contain mixtures of these caloric categories in varying proportions. In this study, students used bomb calorimetry to determine the amount of energy stored in their favorite fast-foods. Ten fast-food samples collected from local restaurants were freeze-dried for a week. A weighed amount of each dried sample was compacted into pellet form and placed in a bomb calorimeter under an oxygen atmosphere. The instrument was standardized using benzoic acid. Computer software was used to determine the temperature change upon ignition of the bomb. Temperature changes resulting from the oxidations of the various foods were used to calculate the heats of combustions for the foods. These values were surprisingly similar for the samples relative to the mass of each sample. French fries had the lowest caloric content of the foods tested. The highest caloric content per gram was seen in a Wendy's junior bacon cheeseburger, probably due to a relatively high fat content.