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Do you want to burn some extra fat during your workouts? Ilex can help. But will it also help you lose body fat?

After the nicotine article a week ago, its about time to take a look at less "toxic" fat burners. As the case may be, researchers from the Faculty of Health and Wellbeing at the Sheffield Hallam University have just published a paper about the ability of Yerba Maté (Illex Paraguariensis | YM) to augments fat oxidation and energy expenditure during exercise at various submaximal intensities (Alkhatib. 2014).

Now, as a SuppVersity Reader youre well aware that an "augmentation of fatty acid oxidation during exercise", alone, is not worth your heard earned money. The question to keep in mind, when were going through the results, is thus: Is Ilex Paraguariensis worth using, or is it just worth writing about in a science magazine?
Alright, now that weve set the scene its about time to take a look at the study design. The study followed a double-blind crossover repeated measures experimental design.

The participants were fourteen healthy adults, seven males and seven females [Mean ± SD: age = 20.8 ± 3.4 yr, height = 171.8 ± 10.0 cm, body mass = 70.4 ± 11.3 kg, body mass index (BMI; in kg/m²) = 23.8 + 0.11]. Participants were assigned randomly to each experimental condition within a period of two weeks.

The Coffee³ Advantage Equation: 3 x 250mL Coffee / Day + 2x4 Weeks ? -1kg Body Fat | learn more

Female participants were studied in days 1 to 7 of their menstrual cycle to minimise the influence of cyclical changes in female hormones. All participants were screened prior to the start of the testing in order to determine that they are free from illness and any type of orthopaedic limitation or injury, or chronic disease.

Moreover, none of the subjects consumed ergogenic aids or tons of caffeine regularly (<200 mg/day) - that doesnt mean they never drank more coffee, but they had to abstain from more than 1.5 cups of coffee, tons of energy drinks caffeine containing soft drinks or medications.

A very reasonable request, if you want to measure significant effects from Ilex Paraguariensis which contains 1.5% (according to Alkhatib. 2014) caffeine and roughly 0.12% theobromine (according to Reginatto. 1999).

The tests & supplements

All participants reported to the Physiology Laboratory on two separate occasions following 10 hrs overnight fast, and each testing session (between 07:00am and 10:00am) was separated by at least three days within two weeks period.

During each visit participants ingested either 1000 mg (2× 500 mg capsule) YM or hydroxypropyl methylcellulose placebo empty capsules (PLC). Two capsules with similar coatings of either YM and PLC capsules were placed within an empty water cup and taken in the same way with a 100 ml of water. The YM capsules contained a standardized ground YM leaves (batch number 0422009/2012) with a natural content of approximately 1.5% caffeine (Rio Trading Company, Brighton, United Kingdom).
Immediately following the ingestion of supplement or placebo, participants rested for 60 minutes in a semi-recumbent position in quiet laboratory condition. For the estimation of FAO and CHO at rest and during exercise, breath by breath cardiorespiratory measurements included oxygen uptake ( ) 2 VO , carbon dioxide production, and respiratory exchange ratio (RER), using an online gas analyzer (Metalyzer Cortex 3B, Leipzig, Germany).

The exercise protocol & its consequences

All participants followed the same incremental exercise assessment using an electromagnetically braked cycling ergometer (Schoberer Rad Messtechnik, SRM, Ergo, Julich, Germany). The ergometer was calibrated before use and similar cycling positions were applied in both tests for each participant, which included adjusting the handlebar and saddle height and distance, crank length and toe clip positions during the first visit and re-apply the same position in the following visit.

The cycling protocol consisted of three-minute incremental stages that were initiated at and increased by 0.5 W/kg body mass. Participants cycled at 60–70 rpm throughout the whole test until volitional exhaustion defined as meeting the at least two of 2 peak VO2 termination criteria: RER value > 1.1, heart rate within 10 beats/min of age predicted maximum heart-rate, or achieving levelling-off of VO2 Peak power (P_peak). Similar verbal encouragement was provided to all participants throughout the exercise tests. All tests were followed by a sufficient cool down for at least 20 min, in which participants consumed at least 200 ml of water, and instructed to stay hydrated and consume at least 2 litres of water during the day of the test.
Interestingly, following the 60 min rest after YM ingestion, no significant difference was found for either resting blood lactate contentration (1.4 ± 0.32 vs. 1.5 ± 0.30 mmol/l) or resting respiratory exchange ratio (0.82 ± 0.08 vs. 0.81 ± 0.05) for PLC vs. YM respectively.

In other words: After the workout there were no measurable difference between the active and placebo treatment. The latter cannot be said of the RER during workouts, though.

Figure 1: Significant decreased RER and higher fatty oxidation rates - two sides of the same fat burning coin and evidence that the ingestion of the YM supplement lead to significant increases in fatty oxidation (Alkhatib. 2014)

As you can see in Figure 1 the effects of the Ilex supplements were significant - statistical significant, but also practically relevant? Probably not. The increase in fatty oxidation was after all paid for with an increase in glucose oxidation (see Figure 2).

Figure 2: The glucose usage during workouts decreases, obviously this leads to greater increases in lactate levels, whether its pro-weight loss is questionable, though. If anything it could increase the time to fatigue (Alkhatib. 2014)

The net energy expenditure, the one thing that really counts, was thus identical. For someone who has to get rid of tons of fat in his blood. The increase in RER may be relevant. For someone who is fit and well-trained, its not really important if he or she burns fat or glucose during the workout - why else would HIIT work so well for losing fat - specifically in lean athletic individuals? Well, the answer is easy: It burns glucose and will thus increase GLUT-4 expression insulin sensitivity and, in the end, also fatty oxidation - to replete the depleted energy stores.
References:

• Godfrey, R. J., et al. "A–Z of nutritional supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance: Part 45." British journal of sports medicine 47.10 (2013): 659-660.
• Pang, Jisook, Youngshim Choi, and Taesun Park. "Ilex paraguariensis extract ameliorates obesity induced by high-fat diet: Potential role of AMPK in the visceral adipose tissue." Archives of biochemistry and biophysics 476.2 (2008): 178-185.
• Reginatto, Flavio Henrique, et al. "Methylxanthines accumulation in Ilex species-caffeine and theobromine in erva-mate (Ilex paraguariensis) and other Ilex species." Journal of the Brazilian Chemical Society 10.6 (1999): 443-446.

Remember: HIIT does not have to happen on the treadmill.

If you havent already done so, I suppose you are currently revising last years training regimen: Reviewing what worked and what didnt work; and thinking about (new) goals and the best ways to achieve them.

If you havent yet decided on what type of cardio training you want to do, todays SuppVersity article may help you make the right endurance / cardiovascular exercise choices for 2015. In that, the headline already revealed: At least 50% of your 2015 "Cardio" training should be high intensity interval training (HIIT) - and here is why.

1. HIIT is more time efficient - Unless you have lost your hob and are looking to kill the newly won time in 2015, you are probably similarly short on time as most of us. Against that background, the mere time efficiency of HIIT workouts are an argument even the most feverish advocates of  low-intensity hour-long cardio cannot deny (Gaesser. 2011; Gillen. 2013).
   

   Figure 1: In contrast to often-heard claims, HIIT is not just a "glucose burner" its also a fat burner. It does (a) increase the oxidation of fatty acids after the workout and (b) increases your muscles and other cells general ability to oxidize fat as fuel (see figure from Talanian. 2007).

   "As few as 6 sessions of HIIT over a 2-week period for a total of about 15 minutes of very intense exercise (equating to approximately 600 kJ or 143 cal) have been shown to increase skeletal muscle oxidative capacity and alter metabolic control during aerobic-based exercise (Gibala. 2008). And 7 HIIT sesssions performed over 2 weeks significantly heightened whole body and skeletal muscle capacity for fatty acid oxidation during exercise in moderately active women (Talanian. 2007). For those who have limited time to work out, this makes HIIT an intriguing option" (Schoenfeld. 2009).

   And even if your goal is not to get fitter, but rather to burn more energy, HIIT can do what steady state cardio will never achieve, i.e. burn 14.5 kcal/min (see "Tabata Workouts: Do They Work & How Energy-Demanding Are They? 14.5 Kcal/Min Sounds Nice, But You Must Earn It!" | learn more). In the end, short workouts will thus increase your 24h energy expenditure to the same extend endless steady-state workouts would do (Skelly. 2014).
   

   "HIIT may help insufficiently active individuals overcome a major barrier to maintaining a physically active lifestyle, that of a perceived lack of time. An added bonus is that from a time:benefit perspective, HIIT may prove to be a good example where less can be more" (Gaesser. 2011).

   And it does not even take a Tabata workout to time-efficiently improve your health. As a SuppVersity reader you will be aware that "4x4 Minutes of HIIT Per Week Thats All It Takes For Already Well-Conditioned Individuals to Stimulate Mitochondrial Growth ? 15% Increase in VO2Max, Peak & Mean Power" | learn more.
2. HIIT has more favorable effects on your glucose metabolism and heart health - You probably have heard that 1h on the treadmill was the ideal exercise for the obese type II diabetic, right? Well, this may in fact be true, but the reason thats ideal for an obese type II diabetic is that even walking on a treadmill is a high intensity exercise for someone who weighs 300-450lbs.
   

   Figure 2: A 2008 study in healthy, normal-weight young women proves: HIIT "cardio" training leads to significantly more pronounced improvements in all three central variables of glucose metabolism than a comparable steady-state "cardio" workout (Trapp. 2008).

   That being said, for all of you with at least a decent amount of fitness, HIIT training with its ability to burn tons of glycogen within just a few minutes should be the preferred mode of exercise. A mode of exercise which has far more potent effects on the expression of the anti-diabetic, anti-obesity and anti-metabolic syndrome proteins AMPK and SIRT-1 than any other form of exercise (Gurd. 2010) and has thus not surprisingly been shown to have superior effects on central markers of glucose metabolism in a 2008 study by Trapp et al. - and that in healthy, lean, young women (see Figure 2).
   
   A similar superiority has been observed by Weston et al. (2013) in patients with lifestyle-induced cardiometabolic disease. Their systematic review and meta-analysis in the British Journal of Sports Medicine indicates that "HIIT significantly increases CRF [cardio-respiratory fitness] by almost double that of MICT in patients with lifestyle-induced chronic diseases." (Weston. 2013).
3. HIIT exercise will help curb your cravings - While steady-state "cardio" has repeatedly been associated with increases in appetite, hunger and most importantly food intake, there is good evidence that "Intensity [is] the Key to Minimize Exercise Induced Cravings?" (learn more)
   

   Figure 3: Effects of exercise duration and intensity on energy intake; exemplary study results from Erdmann et al. (2007, left) and Larson-Meyer et al. (2012, right).

   I dont want to repeat myself on this one. Instead I will just refer you to a recent SuppVersity article on that matter and the plethora of evidence that confirms the negligible or beneficial effects of high intensity interval training on appetite, hunger and how much food you eat and thus ruin any exercise-induced reduction in your daily energy balance (Alkahtani. 2014; Martins. 2014).
   
   

   Figure 4: VAS scores for hunger (A), desire to eat (B), fullness (C), and thirst (D) during REST (black line) and EX (gray line) (n = 15). Hatched rectangles represent the treadmill run/rest; striped rectangles represent the fMRI scan (Crabtree. 2014).

   Before I go on to the #4 on the benefits list, I would yet like to highlight the following result from a recent study from the University college of London:
   

   "Exercise increases neural responses in reward-related regions of the brain in response to images of low-calorie foods and suppresses activation during the viewing of high-calorie foods" (Crabtree. 2014)

   Cant believe what you just read? Look at the figure on the right which depicts the VAS scores for hunger, desire to eat, fullness, and thirst, during REST (black line) and EX (gray line) in N=15 lean healthy men who completed two 60-min trials—exercise and a resting control trial (REST).
   
   Thus, the study clearly confirms the validity of the suggestion to stay scrap your steady-state cardio workouts and replace them with HIIT, in order to finally be able to stick to your diet plans and see the fat loss you are looking for.
4. HIIT ramps up the metabolism instead of ruining it - As long as you dont overdo it by training too often or extending your HIIT sessions to 1h, HIIT will produce a profound "after burn" thats 3x higher than in the case of classic steady-state "cardio" workouts.
   

   Figure 5: EPOC and corresponding additional energy expenditure in the high intensity 3x Wingate group (SPIE) and the 30min continuous exercise group (HIE) during the 30 min right after the workout (Townsend. 2013)

   As a standalone, this previously reported benefit is hardly worth the paper it is printed on. In conjunction with the previously mentioned benefits, however, it is an important benefit of HIIT that must not be underestimated.
5. HIIT is perfectly scalable - Unlike steady-state cardio, where you would have to endlessly increase your workout times, HIIT workouts are easily scalable. You can either...
   

   • HRV = heart rate recovery analyses are a great tool to monitor your training & recovery | learn more

     do an additional interval (volume increase),
      
   • increase the resistance on your training device or run / cycle on a more difficult track (intensity increase),
   • increase the speed at which you run, pedal or row (intensity increase), or
      
   • reduce the time of active rest between the intervals (intensity increase)
   and thus have many more options to tweak the workouts to your individuals needs. For beginners this is not that important. An obese type II diabetic has plenty of room to increase the pace and / or duration of his / her steady-state "cardio" workouts. A trained athletes, on the other hand, will soon hit a wall, when he / she begins to cycle at 90% intensity for 2h everyday.

References:

• Alkahtani, Shaea A., et al. "Acute interval exercise intensity does not affect appetite and nutrient preferences in overweight and obese males." Asia Pacific journal of clinical nutrition 23.2 (2014): 232.
• Crabtree, Daniel R., et al. "The effects of high-intensity exercise on neural responses to images of food." The American journal of clinical nutrition 99.2 (2014): 258-267.
• Erdmann, Johannes, et al. "Plasma ghrelin levels during exercise—effects of intensity and duration." Regulatory peptides 143.1 (2007): 127-135.
• Gaesser, Glenn A., and Siddhartha S. Angadi. "High-intensity interval training for health and fitness: can less be more?." Journal of Applied Physiology 111.6 (2011): 1540-1541.
• Gibala, Martin J., and Sean L. McGee. "Metabolic adaptations to short-term high-intensity interval training: a little pain for a lot of gain?." Exercise and sport sciences reviews 36.2 (2008): 58-63.
• Gillen, Jenna B., and Martin J. Gibala. "Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness?." Applied Physiology, Nutrition, and Metabolism 39.3 (2013): 409-412.
• Gurd, Brendon J., et al. "High-intensity interval training increases SIRT1 activity in human skeletal muscle." Applied Physiology, Nutrition, and Metabolism 35.3 (2010): 350-357. 
• Larson-Meyer, D. Enette, et al. "Influence of running and walking on hormonal regulators of appetite in women." Journal of obesity 2012 (2012).
• Martins, Catia, et al. "Effect of Moderate-and High-Intensity Acute Exercise on Appetite in Obese Individuals." Medicine and science in sports and exercise (2014). 
• Owens, Krystyna. "The effectiveness of high intensity interval training in improving VO< sub> 2</sub> max for performance gains as compared to standard endurance training in athletes." (2013).
• Schoenfeld, Brad, and Jay Dawes. "High-intensity interval training: Applications for general fitness training." Strength & Conditioning Journal 31.6 (2009): 44-46. 
• Skelly, Lauren E., et al. "High-intensity interval exercise induces 24-h energy expenditure similar to traditional endurance exercise despite reduced time commitment." Applied Physiology, Nutrition, and Metabolism 39.999 (2014): 1-4.
• Talanian, Jason L., et al. "Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women." Journal of applied physiology 102.4 (2007): 1439-1447. 
• Townsend JR, Stout JR, Morton AB, Jajtner AR, Gonzalez AM, Wells AJ, Mangine GT, McCormack, WP Emerson NS, Robinson EH, Hoffman JR, Fragala MS Cosio-Lima L. Excess Post-Exercise Oxygen Consumption (EPOC) Following Multiple Effort Sprint And Moderate Aerobic Exercise. Kinesiology. 2013; 45(1):16-21
• Trapp, E. G., et al. "The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women." International journal of obesity 32.4 (2008): 684-691. 
• Weston, Kassia S., Ulrik Wisløff, and Jeff S. Coombes. "High-intensity interval training in patients with lifestyle-induced cardiometabolic disease: a systematic review and meta-analysis." British journal of sports medicine (2013): bjsports-2013.

If we go by the convincing results of the study at hand, the fasted cardio myth is obviously busted.

Sometimes the day youve been waiting for comes faster than youd thought... no, I am not talking about a teens eighteens birthday or Christmas (reminds me, I still have to buy a ton of presents), but rather of the recently hinted at "fasted cardio study" by Brad Jon Schoenfeld, Alan Albert Aragon, Colin D Wilborn, James W Krieger and Gul T Sonmez.

The study of which I wrote only 2 days ago in my article about the 50% increase in fatty acid oxidation in fasted vs. fed morning cardio (learn more). And it is in fact the study which may finally solve the "Is fasted cardio good for your weight loss?"-question.

In contrast to the previously discussed paper, Schoenfeld et al. who started with the common hypothesis that "performing aerobic exercise after an overnight fast accelerates the loss of body fat" (Schoenfeld. 2014), did not content themselves with measures of acute fatty acid oxidation. What they did was a study to investigate the actual changes in fat mass and fat-free mass following four weeks of volume-equated fasted versus fed aerobic exercise in young women adhering to a hypocaloric diet.
Needless to say that this study has the potentially to give us reliable insights with respect to the previously formulated question, because their subjects, twenty healthy young female volunteers were randomly assigned to 1 of 2 experimental groups,

• a fasted training (FASTED) group that performed exercise after an overnight fast (n =10) or
• a post-prandial training (FED) group that consumed a meal prior to exercise (n =10)

not for one or two testing days, but for 4 weeks! The training itself consisted of 1 hour of steady-state aerobic exercise on a regular treadmill (0% incline) and was performed for 3 days per week for the previously mentioned total study duration of 4 weeks.

"Subjects performed a warm-up for the first 5 minutes at an intensity equating to 50% of maximal heart rate (MHR), determined by the formula 220 - age, then increased intensity to 70% MHR for the next 50 minutes, and finished with a 5 minute cool down at 50% MHR. Heart rate monitors (model F7U, Polar Electro Inc, Lake Success, NY) were used to ensure that exercise remained at the appropriate intensity." (Schoenfeld. 2014)

To ensure that (a) the subjects actually trained and they would (b) only do the prescribed standardized volume of exercise, all training sessions were supervised by research assistants who were upper level undergraduate students in exercise science and the subjects were instructed to refrain from performing any additional structured exercise for the duration of the study.
Subjects were provided with customized dietary plans designed to induce a caloric deficit. In that, their total caloric intake was calculated on the basis of the Mifflin-St. Jeor Equation, which yields adequate, but obviously not 100% precise measurements of the resting metabolic rate (max. 10% off in non-obese adults according to Frankenfield. 2005). Since the same method was used for both groups, any possible inaccuracies, due to which the real caloric deficit among the women may not be identical to the calculated one, should carry no real weight, though. And we can simply assume that all women were in the same ~500kcal/day energy deficit the researchers thought to create.

Figure 1: Nutrient composition and total energy intake of the subjects in both groups (Schoenfeld. 2014)

In addition to their regular diet, the adherence to which was monitored on a regular basis, the subjects received a meal replacement shake either

• immediately prior to exercise for the FED group or
• immediately following exercise for the FASTED group,

with this nutritional provision carried out under the supervision of a research assistant. The "Pursuit Recovery" (Dymatize Nutrition, TX) shake you could also buy at your local GNC contains 250 calories, total, and 40 g carbohydrate (from maltodextrin and organic cane sugar), 20 g protein (from whey protein isolate + added leucine), and 0.5 g fat (residues).

Lets  take a look at the results now

As you can see in Figure 2, both groups showed a significant loss of weight (P =0.0005) and fat mass (P =0.02) from baseline, but no significant between-group differences were noted in any outcome measure (which means, that all the differences you see are "random").

Figure 2: Pre- vs. Post-study body composition measures (Schoenfeld. 2014)

As Schoenfeld et al. rightly point out, their findings clearly "indicate that body composition changes associated with aerobic exercise in conjunction with a hypocaloric diet are similar regardless whether or not an individual is fasted prior to training" (Schoenfeld. 2014) - in other words, in this pretty realistic scenario (I hope nobody starves himself after a 1h morning cardio session for another 4-8h) the myth that morning cardio on an empty stomach would accelerate fat loss is thus busted.
References:

• Frankenfield, David, Lori Roth-Yousey, and Charlene Compher. "Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review." Journal of the American Dietetic Association 105.5 (2005): 775-789.
• Van Proeyen, Karen, et al. "Training in the fasted state improves glucose tolerance during fat-rich diet." The Journal of physiology 588.21 (2010): 4289-4302. 
• Schoenfeld, Brad, et al. "Body composition changes associated with fasted versus non-fasted aerobic exercise." Journal of the International Society of Sports Nutrition 11.54 (2014)