How to Burn More Fat During Exercise

Pre Workout Caffeine Increases Energy Expenditure

by: Robbie Durand

Caffeine has long been part of the pre-workout regimen for all gym advocates and professional athletes. Caffeine is well-known as a central nervous system stimulant. Studies have shown that caffeine can help an athlete perform better in a variety of different activities. It has been shown to be a powerful ergogenic aid that is beneficial in athletic performance and training. Caffeine has been shown to increase speed and power output, improve the length an athlete can train, and assist the athlete in resisting fatigue. Caffeine has also been proven to stimulate the brain, which contributes to an athlete’s clearer thinking and ability to concentrate harder on the task at hand. Caffeine is not just good for improving sports performance, but also increases energy metabolism according to new research.

Researchers examined if combining exercise and caffeine supplementation was more effective for promoting acute energy deficits and manipulations to substrate metabolism than exercise alone. Fourteen recreationally-active participants completed a resting control trial, a placebo exercise trial, and a caffeine exercise trial, in which the subjects were given 2 x 3 mg/kg/bw of caffeine 90 min. before and 30 min. after exercise) in a randomized, double-blinded design. Trials were 4 hours in duration with 1 hour of rest, 1 hour of cycling at ~65 % power at VO₂max or rest, and a 2 hour recovery. Two hours after exercise, participants were offered an ad libitum test meal where energy and macronutrient intake were recorded.

At the end of the study, exercise plus caffeine resulted in significantly greater energy expenditure and fat oxidation compared to exercise alone and Control group. Consequently, exercise + caffeine created a greater energy deficit. Caffeine also led to exercise being perceived as less difficult and more enjoyable. Combining caffeine with exercise creates a greater energy deficit and the implications of this protocol for weight loss or maintenance over longer time periods in overweight/obese populations require further investigation.

If you think that’s the end, it gets better for caffeine as a study also showed that caffeine can enhance metabolism after exercise as well. Researchers investigated the effect of acute caffeine intake on post-exercise oxygen consumption (EPOC) after intense resistance training. EPOC is a measure of metabolism after exercise. Fourteen strength-trained men who were caffeine users initially completed one-repetition maximum testing (1-RM) of four exercises: bench press, leg press, lat row, and shoulder press. On each of two days separated by one week, they completed four sets of each exercise to fatigue at 70-80% 1-RM, which was preceded by ingestion of caffeine (6 mg/kg) or placebo. Pre-exercise, indirect calorimetry was used to assess energy expenditure for 35 min.; this was repeated for 75 min. post-exercise while subjects remained seated in a quiet lab.

At the end of the study, results revealed that EPOC was significantly higher with caffeine compared to placebo. With caffeine ingestion, oxygen uptake was significantly higher from 10 min. pre-exercise to 70 min. post-exercise. Respiratory exchange ratio or fat oxidation was significantly different with caffeine versus placebo. Caffeine intake increased total energy expenditure by 15%, but the additional calories burned was minimal (+27 kcal). Caffeine ingestion in individuals regularly completing rigorous resistance training significantly increases EPOC and energy expenditure pre-and post-exercise, yet the magnitude of this effect is relatively small.

Astorino TA, Martin BJ, Wong K, Schachtsiek L. Effect of acute caffeine ingestion on EPOC after intense resistance training. J Sports Med Phys Fitness. 2011 Mar;51(1):11-7.