Looking for Supplements to Fire Up Your Fat Loss? Caffeine Mixed W/ Green Tea Catechins is Still the Go-To OTC Stack

Caffeine + catechines - the CC fat loss stack is the best we've left.

I know people often laugh, when they realize that "Fatburner X" contains mostly caffeine, but if you look at the research that's out there, caffeine is actually the most potent and best researched over-the-counter (OTC) "fat burner" the FDA has not banned, yet.

Let's take the results of a recent study in the Journal of Applied Physiology, for example. In said study, Matthew M. Schubert and colleagues tested whether caffeine supplementation with exercise would lead to higher energy expenditures and fat oxidation during exercise without however (and that's important!) altering the energy intake of the normal-weight, healthy recreationally active study participants.
To this ends, they had their subjects whose mean BMI of 22.7 +/- 2.6 kg/m² was miles away from the BMIs of the average weight loss study participant complete a resting control trial (CON), a placebo exercise trial (EX), and a caffeine exercise trial (EX+CAF) in a randomized, double-blinded design.

In the active, i.e. the caffeine + exercise trial, the subjects consumed 2x3 mg/kg of caffeine (~2x large pots of coffee) 90 min before and 30 min after 1 h of cycling at ~65% of what it would take for the subjects to achieve their maximum O2 consumption (that's not exactly "just pedaling", but not really intense, either), before they rested for another two hours.

Figure 1: Schematic of experimental trials. Syringes show when blood samples were obtained; pills show when caffeine dose (3 mg/kg body mass) was consumed; downward solid arrows represent visual analog scales for appetite; upward dashed arrow represents liquid breakfast at 150 min; gray boxes represent gas exchange data collection (Schubert. 2014).

With the 1h prelude each of the testing sessions during which the subjects either sat around (CON), exercised with placebo ingestion, or exercised with the aforementioned 2x3mg/kg caffeine in their system, each of the sessions lasted 4 hours.

Figure 2: Energy expenditure (kcal) from carbohydrates (CHO) and fat (FAT) during the three trials (Schubert. 2014).

Gas exchange, appetite perceptions, and blood samples were obtained periodically. Two hours after exercise, participants were offered an ad libitum test meal where energy and macronutrient intake were recorded.

Figure 3: Ad libitum food intake on the subsequent meal and corresponding energy balance (energy expenditure during 4h test phase minus energy intake) for all three tests (Schubert. 2014).

As the data in Figures 2-3 tell you, the combination of exercise + caffeine resulted in significantly greater energy expenditure and fat oxidation compared with exercise alone (250 kJ = 59.75 kcal; 10.4 g) and sitting around lazily (3,126 kJ = 747.13 kcal; 29.7 g) (P = 0.05). Furthermore, the researchers observed a trend for reduced energy and fat intake compared with CON (718 kJ = 171.61 kcal; 8 g) (P = 0.055), which led to an effective and significant increase in the energy deficit between the exercise + caffeine and the control group (P = 0.05).

Figure 4: Plot of the mean differences (green/oolong tea or caffeine condition vs. placebo condition) with 95% confidence intervals (CI) for energy expenditure (Hursel. 2011)

Since the subjects also perceived the workout as less difficult and more enjoyable (P = 0.05), the increased energy expenditure and reduced intake "on" caffeine provide a reasonable explanation for the weight loss benefits of caffeine.

These benefits can be significantly promoted, when caffeine used in conjunction w/ green tea catechins (Westerterp-Plantenga. 2010). For this readily available combination Hursel et al. report an average increase in energy expenditure per mg of caffeine + catechins of 100-150kcal per 100mg in their 2011 meta-analysis. That's quite significant, but obviously not scalable to dosages in the multiple-gram range.
References:

• Hursel, R., et al. "The effects of catechin rich teas and caffeine on energy expenditure and fat oxidation: a meta‐analysis." obesity reviews 12.7 (2011): e573-e581.
• Schubert, Matthew M., et al. "Caffeine consumption around an exercise bout: effects on energy expenditure, energy intake, and exercise enjoyment." Journal of Applied Physiology 117.7 (2014): 745-754.
• Westerterp-Plantenga, M. S. "Green tea catechins, caffeine and body-weight regulation." Physiology & behavior 100.1 (2010): 42-46.