Wednesday, September 6, 2017

Healthier, Fitter & Leaner After 12-Day McDonalds Challenge Thanks to HIIT? Plus: TRX®, Fitness ↗ Fatness ↘ in Women

Short news: Sprinting & TRX 
"Have you already burned off that burger you had for lunch today?" If that's a question you're asking yourself regularly, you are at a high risk of misinterpreting a recent study by Christian Duval et al. (2017) as a license to eat how much you want, whatever you want, whenever you want. Unfortunately, a 12-week study in which young, healthy subjects were allowed to consume only three more or less energy-adequate meals is not representative of the futile "if you eat more/worse, just exercise more"-approach to diet and exercise.

Apropos exercise, if you're still looking for the right exercise to get or stay fit and healthy, TRX training, the suspension training bodyweight exercise that has purportedly been developed by/for US Navy Seals seems to actually live up to some of its promises of developing strength, balance, flexibility and core stability - overall fitness (VO2max) improvements are yet probably its greatest strength, a strength that comes with "unintended", but significant reductions in body fat in the overweight young women who participated in a recent 8-week Iranian randomized, controlled study by Dolati et al. (2017).
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  • HIIT protects young, healthy individuals from fast food induced insulin resistance and reduced cardiovascular health, "in large part", study shows (Duval 2017) -- "You cannot outrun an obesogenic diet" - I guess you've heard or read that before (maybe even at the SuppVersity) and the study at hand doesn't falsify this truism. What it does, however, is to remind us that "an obesogenic diet" is any hypercaloric diet. A fast food diet, on the other hand, is not necessarily hypercaloric. In fact, you could lose a lot of weight if you ate at McDonald's every day but kept your total energy intake 30% below your baseline requirements.
    Either three McDonald's meals a day are not as bad as people think or HIIT protects young, healthy individuals from the bad effects. In the absence of a "Mc Donald's-only" control group, the study at hand cannot really answer this question. Based on previous evidence the former answer is more likely, though.
    In other words: Fast food per se is not obesogenic. It is, however, due to its high energy density, low satiety effect and nutrient density, and the pro-diabetic combination of high GI carbs and unhealthy fats that are so characteristic of Western fast foods, pro-diabetic and may deteriorate your blood lipids and other CVD-relevant blood markers in ways that have been found to be associated with an increased heart disease risk. Accordingly, the question whether high-intensity-interval training (HIIT) can counteract the deleterious effects of a fast food diet on the cardiometabolic profile of young healthy men, which was addressed in a recent study from the Université du Québec à Montréal (Duval 2017), is of fundamental importance.

    In the 14-day study, fifteen men, all fit, healthy and physically active (>150 min of physical activity/week), were subjected to an exclusive fast food diet from a popular fast food restaurant chain, McDonald's, where they consumed ...
    • a sandwich (e.g., Egg McMuffin®, or Sausage McMuffin®), hash browns and a small fruit drink or coffee for breakfast, and
    • a sandwich (e.g., Big Mac®, McChicken®, or Quarter Pounder with Cheese®), medium fries and a non-diet medium soft drink) for lunch and dinner and an optional snack
    Since this was a noncontrolled study, all participants were asked to perform high-intensity-interval training (HIIT) (15 × 60 sec sprint intervals (~90% of maximal heart rate) interchanged with 60 sec active recovery (walking) + 5min warm-up and 5-min cool down) on a treadmill, every day. That's a clear weakness of the study as it simply assumes that the health parameters the scientists measured, i.e. body composition (DXA), cardiometabolic profile (lipid, hepatic enzymes, glycated hemoglobin, glucose, insulin, hsC-reactive protein (hs-CRP) and blood pressure) and estimated maximal oxygen consumption (VO2 max) pre- and post-experiment would deteriorate significantly within only two weeks.
    Figure 1: When combined w/ HIIT the fast food diet rather improves than worsens important parameters of body composition, fitness, and glucose metabolism (Duval 2017 | all changes were stat. sign.)
    If it were not for the significant improvements of fat and lean body mass, estimated VO2 max, fasting glucose, serum lipoprotein(a) and hs-CRP after the intervention (p < 0.05), the scientists observed, the study would thus be useless. If said parameters had not improved, but worsened, it would, after all, be impossible to know whether and to which extent the worsening of the subjects body composition, metabolic and heart health would have been ameliorated by the HIIT intervention.
    Figure 2: If you look at the totality of the changes in glucose and lipid metabolism and the inflammatory status and ignore that only the changes in fasting glucose, HDL-cholesterol, and hs-CRP were statistically sign., it seems as if McDonald's + HIIT was much healthier than what the subjects usually did.
    This problem exists, however, for the significant reductions in HDL-cholesterol (p < 0.002) and the lack of change of the triglycerides/HDL-cholesterol ratio. Due to the lack of a "fast food only"-control group it's impossible to tell if the decline in HDL would have been more pronounced and the triglyceride/HDL ratio would have increased in a non-existent "fast foot only"-group. The researchers were thus lucky that their study turned out to produce results the scientists could interpret as follows: "In conclusion, in large part, insulin resistance and the cardiometabolic profile of young healthy individuals seems to be protected by HIIT from a fast food diet" (Duval 2017).

    Before you rejoice, jump into your car and head to the next McDonald's drive-in restaurant, remember: We are talking about a two-week study in which the energy intake was limited by certain rules, so that the average participant ended up consuming 3441 ± 337 kcal/day and expending 3503 ± 373 kcal/day (that's a 60kcal deficit |the subjects' individual energy expenditure was monitored by a portable mini SenseWear armband the validity of which has been confirmed in St-Onge 2007, Drenowatz 2011, and Ryan 2013 - needless to say that conducting the whole study in a metabolic ward would have been better ;-) - against that background it's no wonder that the sixteen young men didn't balloon up or saw significant negative effects on important health markers.
    Figure 3: The experimental diet could for sure have been worse and more obesogenic (data from Duval 2017).
    And, by the way, with a macronutrient ratio of 12%, 49% and 39% for protein, carbohydrates, and fats, their macros weren't much worse than the average Westerner does, anyway. In fact, it would be interesting to run their McDonald's diets through MyFitnessPal to compare their micronutrient intake to the one of the average American. I am not sure how much worse the McDonald's diet really was... speaking of calculations: I calculate or hope that we may see a controlled follow-up study - ideally with a longer study period ;-)
  • TRX-Training an option an excellent training option for overweight (non-obese!) women (Dolati 2017) -- If you look at TRX' marketing campaign, the 24 overweight women (age of 29.41 ± 4.48, height 162.35 ± 4.97cm, weight 73.4 ± 5.47kg and BMI 27.85 ± 2.02 kg/m2) who participated in a recent study at the Islamic Azad University in Teheran clearly don't belong to the producers' target group - a big mistake? It almost looks like it.
    Overweight women are not yet a target of the TRX' marketing. Considering that this study shows that TRX workouts prevent a 2% increase in body fat and shed sign. 2% body fat in 8 weeks (24 sessions) this may be a mistake... or, maybe, those responsible may simply want to signal that after half a year of TRX the ladies in the study would look like the shredded girls in the campaign - unfortunately, that won't happen w/out dieting.
    Over the course of the 8-week study, all participants performed 24 workouts (three workouts per week). The training duration from the first week up to the last week increased from 12 to 30 minutes and the exercise intensity from 50 to 80 HRmax ("minimal" rest between exercises - usally it's 30s to switch from one position to the other in TRX).

    Prior to the implementation of the training program, the performance indicators and body composition were measured and blood test was also conducted for determining the lipid profile. After eight weeks of practicing, all of these tests were taken once more.
    Figure 4: Rel. changes in BMI and body fat % and VO2max in the TRX and control group (Dolati 2017).
    The body fat percentage of the subjects in the treatment group dropped from 39.8 to 36.97% (p = 0.001), their body fat mass decreased from 28.22 to 26.32 (p = 0.001), their upper-body muscle strength increased from 13.85 to 15.21 kg (p=0.001), and their the lower body muscle strength from 126.78 to 132.24 (p=0.001). The women in the control group, on the other hand, saw no such improvements - in fact, their body fat percentage increased from 36.67 to 38.22% while their muscle mass and strength remained virtually identical.

    In the absence of additional cardio training the subjects in the TRX group also saw a highly significant increase in VO2max from 55.05 to 61.89 ml/kg/min (p= 0.002) - probably a consequence of the fact that TRX training is, in contrast to strength training, not standardized by 1-RMs, but by heart rate. With the target heart rate for the study at hand being increased from 50-60% to 80% of the maximal heart rate from the first to the last week of the study, the intervention obviously provided an effective stimulus for VO2max gains (note: there was no change in the non-exercised control | see Figure 4).

    If you look at the results, TRX is neither an efficient mass/strength builder nor the best tool to shed body fat (if you hate "weights" want a strong aerobic component and still build mass/strength and lose body fat, check out kettlebells). The significant VO2-gains and the proven increase in muscle activity during core training still make it attractive - even if it's only as a means to diversify your training program.
Be a glutton from time to time! Believe it or not, three days of overfeeding won't make you fat, even with 1,500 extra-calories per day and more than 50% of the energy coming from carbohydrates | more
Bottom line: Trying to outrun a bad diet is, unfortunately, still a common practice ... a practice you don't want to follow; that does not mean, though, that the Duval study was irrelevant. It does, after all, confirm that you don't have to be afraid to get fat or, even worse, sick from the occasional fast food meal. I've written about the futility of the idea that every 'nutritional mistake' is punished with obesity, diabetes, or both (e.g. "Can You Get Fat in Just Three Days?" | read it)... let's be honest: the stress you may experience after "sinning" if you hold such beliefs is going to be worse for your physique, overall and metabolic health than the occasional burger with fries - at least, if you (a) understand that "calories count" and (b) do not fall completely off the wagon and subscribe to the "as much of everything I want at anytime I want it"-dietary approach a significant number of our fellow human beings subscribe to.

And in case things go south, anyway, remember: you don't have to wait for new years eve to start a new - whether this restart involves TRX, is obviously up to you. If we go by the results of Dolati et al. (2017), however, this is maybe not the worst exercise equipment to use. Whether it's right for you, though, is something only you can answer: if you like it, fine; if you hate it, find something else - enjoyment is, after all, a key determinants of exercise adherence (Richard 1997) and adherence is the key to success in both diet (Alhassan 2008) and training (e.g. Van Gool 2005) | Comment!
  • Alhassan, S., et al. "Dietary adherence and weight loss success among overweight women: results from the A TO Z weight loss study." International journal of obesity (2005) 32.6 (2008): 985.
  • Dolati, Mahya, Farshad Ghazalian, and Hossein Abednatanzi. "The Effect of a Period of TRX Training on Lipid Profile and Body Composition in Overweight Women." International Journal of Sports Science 7.3 (2017): 151-158.
  • Duval, Christian, et al. "High Intensity Exercise: Can It Protect You from A Fast Food Diet?." Nutrients 9.9 (2017): 943.
  • Drenowatz, Clemens, and Joey C. Eisenmann. "Validation of the SenseWear Armband at high intensity exercise." European journal of applied physiology 111.5 (2011): 883-887.
  • Richard, M., et al. "Intrinsic motivation and exercise adherence." Int J Sport Psychol 28.4 (1997): 335-354.
  • Ryan, Jennifer, and John Gormley. "An evaluation of energy expenditure estimation by three activity monitors." European journal of sport science 13.6 (2013): 681-688.
  • St-Onge, Maxime, et al. "Evaluation of a portable device to measure daily energy expenditure in free-living adults." The American journal of clinical nutrition 85.3 (2007): 742-749.
  • Van Gool, Coen H., et al. "Effects of exercise adherence on physical function among overweight older adults with knee osteoarthritis." Arthritis care & research 53.1 (2005): 24-32.