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| No this is not Liza Oz after taking Mehmet's beloved RK supplements ;-) |
Too much blubber? "Grab the rasp and berry it off!" Ah, well...
Hold on, another of those "proprietary blend studies"? Can we even trust the data? Allegedly, the authors Lopez and Ziegenfuss have worked for raw material suppliers, nutraceutical and dietary supplement companies in the past and openly declare that in the paper at hand, but guess how many of the authors of studies on medications have worked for the pharma industry and were / are still involved in the development of the respective drugs? If we really started to question the results of each and every study on the basis of the mere assumption that it was a product pimp job, we would probably have to discard 95% of the currently available research. Just remember: In 99.9% of the cases it's the conclusions and interpretations that can be problematic, and not the data, itself.
If we take a closer look at the ingredient profile of "METABO", we notice that Dr. Oz's beloved raspberry ketones are right on the top of the ingredient list of the 1,000mg proprietary blend single 2-cap serving of the product contains. With caffeine and a 10% synephrine extract from citrus aurantium, which are usually dosed at around 200mg and 100-150mg (to deliver 10-15mg of synephrine as part of the Advantra-Z formula; cf. Seifert. 2006), respectivley, being the #2 and #3 on that list, we can safely assume that the maximal amount of Razberi K in a single serving of the supplement is 600mg.... that's actually quite nice, because that's so little that we do not even have to use a calculator to know that this is hilariously underdosed compared to what the rodents in the heavily cited anti-obesity (I repeat: anti-obesity, not weight loss) trials by Morimoto et al. reaceived as part of their regular chow (1-2% of the whole chow was nothing but pure raspberry ketones; cf. Morimoto. 2005) |
| Figure 1: Body weight, fat mass, lean mass and waist circumference after 4 and 8 weeks of dieting + exercise + supplement / placebo (Lopez. 2013) |
And secondly, the low dose of raspberry ketones left some room for the other ingredients, of which you can see in the data I plotted in figure 1 that they were very well capable of promoting the weight loss success of the 70 "obese but otherwise healthy subjects" in the Lopez study.
Effects? Yes! Effects due to raspberries? Questionable.
There is no debating that the combination of multiple "thermogenic", appetite suppressing and anti-oxidant / insulin sensitizing weight loss adjuvants in METABO did promote the loss of fat mass over what the diet + exercise progra alone could achieve. The former, i.e. the diet, had by the way been designed by a "state-licensed, registered dietitian" to provide three meals and two snacks per day (the latter are obviously useless; cf. Whybrow. 2007) and a total energy intake that would deliver approximately 500 kilocalories per day less from a 40% carbohydrate, 30% protein and 30% fat diet than the subjects actually "required" (dietary requirements that were calculated with the Mifflin-St. Jeor equation and an activity factor of 1.2; learn more).
This dietary regimen was accompanied by an 8-week workout regimen of which I would usually write that it was "surprisingly sound". In view of the fact that the study, appeared in the Journal of the International Society of Sports Nutrition and not Obesity or JAMA it is yet only "sound" and not surprising that the subjects had to work out three times per week for 60 minutes of which not a single minute was wasted on steady state cardio in the non-existing fat-burning zone. Instead, they performed a...
- 10 minute warm-up (i.e. walking, light jogging, or biking),
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| It sure sounds ufair, but women have a harder time shedding fat. Against that background it's all the more important for the average "I don't eat meat" lady to get her share of fat burning protein - after all a reasonable amount of protein speed fat loss in both sexes (learn more). |
- 30 minutes of circuit training (upper and lower body each session, which consisted of a combination of
- mountain climbers, squat thrusts,
- jumping jacks, squat kickouts, walking lunges,
- push-ups, dips,
- resistance band elbow flexion, extension and
- shoulder presses,
- additional 10 minutes abdominals/core work, and
- a subsequent 10 minutes cool down/stretching
Dieting alone "fails", the supplement "works" - what's more surprising
Now, the first thing that comes to mind, whenever a diet fails, is a bogey called "non-adherence". With the supervised and controlled exercise protocol and the official data on the energy and nutrient intake not showing significant inter-group differences, it is however difficult to pin the success / failure of the groups exclusively on non-compliance. The consistently higher food cravings in the placebo group do yet put another questionmark behing behind the accuracy of the already notoriously unreliable self-reported food intakes.
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| Figure 2: Cravings for energy, sweets, fatty fast food, fat in general, carbs and healthy foods in the subjects in the placebo and MTEABO group (Lopez. 2013) |
Significant fat loss without significant health benefits? Surprisingly, the measured markers of glucose and lipid metabolism, namely total cholesterol, HDL, LDL, cholesterol/HDL ratio and TAG did not show significant improvements in any of the groups. There was however "a strong trend (p < 0.07) for TAG concentrations to decrease more in the METABO group (-15.9%) compared to the placebo group (-2.6%)" (Lopez. 2013) and a significant decrease in leptin that was likewise observed exclusively in the supplement group.
Since hunger is associated with increased ghrelin levels and those have only recently been confirmed as a significant correlate and potential cause for weight loss interventions to fail (Liu. 2013), it may in the end not even matter, whether the subjects gave in to their cravings and "cheated" or whether they starved and their bodies simply stopped shedding body fat - the net result would have been identical in both conditions and if a single agent or the synergy of all of the ingredients in METABO was responsible for the satiety effect the weight loss advantage would in fact have been brought by the dietary supplement.  |
| If you clicked on the links that redirect you to the overviews of SuppVersity articles on capsaicin, piperine, citrus aurantium etc. you will have realized that many of them were also on my list of PPAR-gamma antagonists (learn more). |
- fat loss benefits (I initially wanted to write "effects", but that's probably an exaggeration) of ingredients such as caffeine (Greenway. 2001), capsaicin (Snitkner. 2009), citrus aurantium (Bent. 2004; Stohs. 2012), ginger (Mahmoud. 2013), piperine, and / or
- satiety effects of caffeine (Westerterp-Plantenga. 2005a), capsaicin (Westerterp-Plantenga. 2005b), ginger (Mansour. 2012), ...
Against that background it is pretty useless to single out any of the ingredients, but if we wanted to do just that, it would certainly be the raspberry ketones which are the least-proven weight-loss adjuvant in Prograde Metabolism - an ingredient celebrated as the goto fat burner by the uneducated mainstream and an ingredient without any scientific backup from human studies. So, if I had to answer the gonzo rhetoric question in the title of this article in a binary = yes/no fashion, the most likely answer would be "no!" ;-)
References:
- Bent S, Padula A, Neuhaus J. Safety and efficacy of citrus aurantium for weight loss. Am J Cardiol. 2004 Nov 15;94(10):1359-61.
- Greenway FL. The safety and efficacy of pharmaceutical and herbal caffeine and ephedrine use as a weight loss agent. Obes Rev. 2001 Aug;2(3):199-211.
- Ogawa Y, Akamatsu M, Hotta Y, Hosoda A, Tamura H. Effect of essential oils, such as raspberry ketone and its derivatives, on antiandrogenic activity based on in vitro reporter gene assay. Bioorg Med Chem Lett. 2010 Apr 1;20(7):2111-4.
- Lopez HL, Ziegenfuss TN, Hofheins JE, Habowski SM, Arent SM, Weir JP, Ferrando AA. Eight weeks of supplementation with a multi-ingredient weight loss product enhances body composition, reduces hip and waist girth, and increases energy levels in overweight men and women. Journal of the International Society of Sports Nutrition. 2013; 10(22).
- Mahmoud RH, Elnour WA. Comparative evaluation of the efficacy of ginger and orlistat on obesity management, pancreatic lipase and liver peroxisomal catalase enzyme in male albino rats. Eur Rev Med Pharmacol Sci. 2013 Jan;17(1):75-83.
- Mansour MS, Ni YM, Roberts AL, Kelleman M, Roychoudhury A, St-Onge MP. Ginger consumption enhances the thermic effect of food and promotes feelings of satiety without affecting metabolic and hormonal parameters in overweight men: a pilot study. Metabolism. 2012 Oct;61(10):1347-52.
- Morimoto C, Satoh Y, Hara M, Inoue S, Tsujita T, Okuda H. Anti-obese action of raspberry ketone. Life Sci. 2005 May 27;77(2):194-204.
- Snitker S, Fujishima Y, Shen H, Ott S, Pi-Sunyer X, Furuhata Y, Sato H, Takahashi M. Effects of novel capsinoid treatment on fatness and energy metabolism in humans: possible pharmacogenetic implications. Am J Clin Nutr. 2009 Jan;89(1):45-50.
- Stohs SJ, Preuss HG, Shara M. A review of the human clinical studies involving Citrus aurantium (bitter orange) extract and its primary protoalkaloid p-synephrine. Int J Med Sci. 2012;9(7):527-38. Epub 2012 Aug 29.
- Westerterp-Plantenga MS, Lejeune MP, Kovacs EM. Body weight loss and weight maintenance in relation to habitual caffeine intake and green tea supplementation. Obes Res. 2005a Jul;13(7):1195-204.
- Westerterp-Plantenga MS, Smeets A, Lejeune MP. Sensory and gastrointestinal satiety effects of capsaicin on food intake. Int J Obes (Lond). 2005b Jun;29(6):682-8.
- Whybrow S, Mayer C, Kirk TR, Mazlan N, Stubbs RJ. Effects of two weeks' mandatory snack consumption on energy intake and energy balance. Obesity (Silver Spring). 2007 Mar;15(3):673-85.