Background: Energy drink consumption is prevalent among college students, with recent studies indicating that >30% of college students consume energy drinks daily. These drinks range in caloric content, but typically contain caffeine in amounts greater than 1-2 cups of coffee. Additionally, they employ marketing claims such as “increased energy”, “increased attention/alertness”, “increased metabolism”, and “increased fat-burning”. While stimulants such as caffeine are widely known to increase energy and alertness, the claims related to the increased metabolism and fat-burning effects of these drinks have received less attention. Thus, the purpose of this study was to evaluate the claims (“accelerates metabolism” and “burns body fat”) on a commercially available, sugar-free energy drink that contains 200 mg of caffeine (~ 2.5, 6 oz cups of coffee) and a proprietary mix of guarana extract, green tea extract, taurine, ginger root extract, and glucuronolactone. Methods: Eleven college-aged (22±1y) subjects were randomly assigned to consume 12-ounces of a commercially available energy drink (Celsius Live Fit™) or 12-ounces of a placebo drink (0 calorie sparkling water) 1 hour before the measurement of resting metabolic rate (RMR) at trial visit 1. Approximately a week later (trial visit 2), subjects returned, and a second RMR was conducted 1 hour after consuming the other drink. RMR (kcal/hr) and fat metabolism (kcal/hr) were measured using indirect calorimetry. Twenty-four hour physical activity level and macronutrient intake did not differ between the trials. Results: Ingestion of Celsius resulted in an elevated metabolic rate (76±14 kcal/hr) compared to placebo (69±15 kcal/hr) (p< 0.01). Fat metabolism was not significantly affected by Celsius ingestion. Conclusion: Though the increase was modest, the claim that Celsius “accelerates metabolism” was supported by the results of this study. The claim that it “burns body fat” was not supported.
Authors: Emma Marcille, Rachel Tumbleson, Brendon Cox, Kaitlyn Dick, Monique Esbrand, Kayla Fry, Addie Karlblom, Taylor Maxwell, Caitlyn Picard, Brittany Stanko, Austin Waterwall, Lydia Wolferst
Faculty Advisor: Kyle L. Timmerman, Kinesiology, Nutrition and Health
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