February 2012: Research Updates for Personal Trainers
Fat
burners: nutrition supplements that increase fat metabolismobr_908
841..851
A. E. Jeukendrup and R. Randell
Obesity Reviews (2011) 12, 841–851
The term ‘fat burner’ is used to describe nutrition supplements that are claimed to acutely increase fat metabolism or energy expenditure, impair fat absorption,increase weight loss, increase fat oxidation during exercise, or somehow cause long-term adaptations that promote fat metabolism. Often, these supplements contain a number of ingredients, each with its own proposed mechanism of action and it is often claimed that the combination of these substances will have additive effects. The list of supplements that are claimed to increase or improve fat metabolism is long; the most popular supplements include caffeine, carnitine, green tea, conjugated linoleic acid, forskolin, chromium, kelp and fucoxanthin. In this review the evidence for some of these supplements is briefly summarized. Based on the available literature, caffeine and green tea have data to back up its fat metabolism-enhancing properties. For many other supplements, although some show some promise, evidence is lacking. The list of supplements is industry driven and is likely to grow
COMMENTS:
There are many ways to turn off fat burning: eating too much, exercising too little, high insulin levels, not sleeping enough, stress levels and on and on. Unfortunately, there are not too many ways we can turn on fat burning. The obvious candidates are being physically fit, eating less than we expend and keeping insulin levels low. There are numerous supplements on the market that are promoted as ‘fat burners’. But do they perform as they are advertised and do they really make a difference to a client’s fat loss efforts? Drs Jeukendrup and Randell have performed an up to date examination and review of the supplements that claim to increase fat burning. Of the many that are advertised, only green tea and caffeine have scientific support for their efficacy.
TAKE HOME:
The majority of legal supplements promoted to increase fat burning do not work. Both green tea and caffeine are the exceptions. Save you client’s money, and have them emphasize higher energy expenditure, lower caloric intake, good sleep and stress reduction to maximize fat loss results. This is where the best outcomes are to be found. If you wish to incorporate two scientifically proven ‘helpers’, then you may wish to consider adding green tea (500mg of EGCG) or caffeine (2-4mg per kg of body mass) prior to exercise.
Nutraceutical Supplements for Weight Loss: A Systematic Review
Kavita Poddar, Sanjivani Kolge, Lena Bezman, Gerard E. Mullin, and Lawrence J. Cheskin,
Nutrition in Clinical Practice Volume 26 Number 5October 2011 539-552
In summary, there is a dearth of data on the effect of dietary supplements on body weight loss in humans. Thepublished data to date provide inconclusive evidence on the usefulness of different dietary supplements for weightloss. Caution must be exercised before recommending the use of these supplements for weight loss, as there is evidencethat some may produce harmful effects. When using any of these alternative therapies as adjuncts for weightcontrol, one must remember that, although derived from natural sources, they may nonetheless exhibit powerfulpharmacologic effects and are thus still “medicines.” For example, foxglove, the plant origin of digitalis, has wellknowntoxic effects comparable to those seen with pharmacologic digitalis dosing. Therefore, it is extremely important to use these supplements wisely and in limited amounts.
In closing, it is fitting to highlight that perhaps the most general and safest alternative/herbal approach to weight control is to substitute low-energy density foods for high-energy density and processed foods, thereby reducing total energy intake. By taking advantage of the low-energy density and health-promoting effects of plant-based foods, one may be able to achieve weight loss,or at least assist weight maintenance without cutting down on the volume of food consumed or compromising its nutrient value. Because of the lack of quality, safety, and efficacy of many of the supplements discussed in this article, their use should generally be discouraged. Some supplements (eg, guar gum and chitosan) seem to show no efficacy. Ephedra, although quite effective for weight loss, is very well known for its adverse effects, and products containing even traces of this supplement should be discouraged. Many other supplements lack enough clinical evidence to support their role in weight loss, or studies have resulted in contradictory evidence. These supplements include conjugated linoleic acid, ginseng, glucomannan, green tea, HCA, L-carnitine, and psyllium.
Although data on some supplements are encouraging, they may lack sufficient data or have been evaluated in poorly conducted clinical trials. Further studies are needed to evaluate the effectiveness of “herbal medicines” for weight loss and weight maintenance. Given the fact that conventional weight loss methods are not often effective long term, nonprescription dietary supplements have become popular among those seeking quick results. However, given the generally limited evidence of efficacy, even the smallest undesirable side effect of these supplements can shift the risk-benefit ratio to the unfavorable.
Thus, in conclusion, based on the available science, recommending nonprescription dietary supplements as an adjunct to weight loss currently cannot be stronglyrecommended.
COMMENTS:
This review does an excellent job at pointing out the obvious that has been lost in the personal training industry for sometime: fat loss is best achieved by increasing energy expenditure above energy intake. Any effect of supplements are totally insignificant when compared to the benefits achieved through creating a negative energy balance. This review thoroughly examines all the available literature on supplements promoted as fat loss aids. Only the following had “some evidence” (which really means “much more research is needed before recommending to clients”): Psyllium, Konjac root fiber, Green tea, Cissus quadrangularis, and Citrus aurantium.
TAKE HOME:
Personal trainers and our clients are constantly looking for ways to assist in fat reduction. Many of us utilize supplements to this end. Most of us are not really aware of the level of evidence for the supplements. There are many supplements that have plausible theoretical pathways to aid fat loss. Many are involved in improving insulin sensitivity or have a role in fat oxidative pathways. However, when examined in humans over many months with a placebo group, most supplements have no effect. Every trainer should be able to answer intelligently any questions a client may have on how does the supplement work? And how much extra gain will I expect to see? Answers such as, “this improves insulin sensitivity” or “this increases fat burning” are unacceptable. If we don’t know how much extra gain a client will receive, how the supplement works and what the studies have shown on the supplement (or worse, we are only relying on an internet site or a course we attended which told you how to prescribe supplements based on someone’s body composition) we are doing a great disservice to our clients and wasting their money and this often results in losing credibility. So, save your client’s money. Do our homework and stop prescribing supplements that have limited to no value in helping clients lose fat.
Effects of 4 weight-loss diets differing in fat, protein, and carbohydrate on fat mass, lean mass, visceral adipose tissue, and hepatic fat: results from the POUNDS LOST trial.
de Souza RJ, Bray GA, Carey VJ, Hall KD, Leboff MS, Loria CM, Laranjo NM, Sacks FM, Smith SR.
American Journal of Clinical Nutrition First published ahead of print January 18, 2012 as doi: 10.3945/ajcn.111.026328
Weight loss reduces body fat and lean mass, but whether these changes are influenced by macronutrient composition of the diet is unclear.We determined whether energy-reduced diets that emphasize fat, protein, or carbohydrate differentially reduce total, visceral, or hepatic fat or preserve lean mass.In a subset of participants in a randomized trial of 4 weight-loss diets, body fat and lean mass (n = 424; by using dual-energy X-ray absorptiometry) and abdominal and hepatic fat (n = 165; by using computed tomography) were measured after 6 mo and 2 y. Changes from baseline were compared between assigned amounts of protein (25% compared with 15%) and fat (40% compared with 20%) and across 4 carbohydrate amounts (35% through 65%).At 6 mo, participants lost a mean (±SEM) of 4.2 ± 0.3 kg (12.4%) fat and 2.1 ± 0.3 kg (3.5%) lean mass (both P < 0.0001 compared with baseline values), with no differences between 25% and 15% protein (P ≥ 0.10), 40% and 20% fat (P ≥ 0.34), or 65% and 35% carbohydrate (P ≥ 0.27). Participants lost 2.3 ± 0.2 kg (13.8%) abdominal fat: 1.5 ± 0.2 kg (13.6%) subcutaneous fat and 0.9 ± 0.1 kg (16.1%) visceral fat (all P < 0.0001 compared with baseline values), with no differences between the diets (P ≥ 0.29). Women lost more visceral fat than did men relative to total-body fat loss. Participants regained ∼40% of these losses by 2 y, with no differences between diets (P ≥ 0.23). Weight loss reduced hepatic fat, but there were no differences between groups (P ≥ 0.28). Dietary goals were not fully met; self-reported contrasts were closer to 2% protein, 8% fat, and 14% carbohydrate at 6 mo and 1%, 7%, and 10%, respectively, at 2 y.Participants lost more fat than lean mass after consumption of all diets, with no differences in changes in body composition, abdominal fat, or hepatic fat between assigned macronutrient amounts.
COMMENTS:
In our industry, clients have been often taught to become obsessed with counting grams of carbohydrate. In my younger years, we were obsessed with counting calories and in my parent’s day, it was counting grams of fat. It saddens me to think that so many clients of personal trainers have been taught to avoid carbohydrate because it will make them fat. Worse, many clients – who already may not particularly enjoy exercise – are attempting to perform high intensity weight training or intervals on low carbohydrate diets and because their muscle glycogen stores and blood glucose levels are so low, now find exercise even less appealing and therefore compliance is further reduced.
This study, just published in the prestigious American Journal of Clinical Nutrition, examined diets of differing carbohydrate, fat and protein levels, while keeping calories similar. Professor Marion Nestle has recently commented on the paper and has said that this study “went to a lot of trouble to prove the obvious. When it comes to weight loss, how much you eat matters more than the proportion of fat, carbohydrate, and protein in your foods.”
“Researchers at the Pennington Biomedical Research Center got volunteers to eat diets that were supposed to differ in proportions of fat (40% vs 20%), carbohydrates (35% vs. 65%), and protein (25% vs. 15%). The results of the study are consistent with the findings from many previous studies (1) The major predictor for weight loss was adherence to the diet, (2) People on all of the diets lost weight by six months, but regained some of it by two years. (3) The study had a high drop-out rate (hence the importance of adherence), and (4) It was hard for people to stick to the diets, especially those at the extremes of one dietary component or another."
"Some people find it easier to stick to diets that are higher in protein and fat. I’m guessing that proponents of low-carbohydrate diets will argue that none of the diets in this particular study was really low in carbohydrate."
"But studies show that people have a hard time adhering to diets that are very low in carbohydrate. The low range in this study—35%—is at the lower end of acceptability for many people."
"The bottom line: all diets work if you stick to them." Professor Nestle’s full comments can be found here: http://www.foodpolitics.com/2012/01/want-to-lost-weight-eat-less/
The Impact of Dietary Changes and Dietary Supplements on Lipid Profile: Systematic Review/Meta-analysis
Jingbo Huang, Jiri Frohlich, and Andrew P. Ignaszewski,
Canadian Journal of Cardiology 27 (2011) 488–505
With a growing number of dietary interventions that claim to improve lipid profile, it is important to ensure that these claims are evidence based. The objective of this study was to make recommendations for dietary regimens by analyzing their effectiveness and the level of evidence. We searched MEDLINE as well as the Cochrane Database of Systematic Reviews for nutritional studies. Meta-analyses and randomized controlled trials published in English and including data on the effect on blood lipid levels were used. Randomized controlled trials were included if they were at least 4 weeks in duration and had a minimum of 50 participants. We identified 22 different dietary interventions and reviewed 136 studies published between January 1990 and December 2009 that met our inclusion criteria. Our literature review showed that to improve lipid profile, the following regimens can be recommended fully: Mediterranean and Portfolio diets; low-fat diet; diet high in soy protein, fibre, or phytosterols; whole grain foods, and omega-3 fatty acid supplementation. The consumption of nuts, a diet high in carbohydrates and protein, green tea, and red wine, as well as the supplementation with policosanol and red yeast rice extract, can be considered for improvement of the lipid profile, while the supplements of guggulipid, garlic, chromium, vitamin C, magnesium-pyridoxal-phosphate-glutamate, tocotrienols, and absorbitol cannot be recommended.
COMMENTS:
This is my favourite nutrition paper of 2011. The authors explain that statin medication may reduce LDL-C by up to 60% but only reduce the risk of heart disease by less than 50%, whereas diet and lifestyle changes have shown an 80% reduction in risk of heart disease. Many individual foods and foods in combination ("diet") play an impressive role in heart protection. This study reviews the latest evidence for these foods in heart health and lists the following to be incorporated into a heart disease protection diet: viscous fibres (in oats, barley, and psyllium) and plant sterols but also of soy protein, nuts, red wine, and green tea and the supplements (red yeast rice, omega-3 fatty acids, and polycosanols). The review further supports the use of diets including the Mediterranean, portfolio (combined high fibre, plant sterols, soy and nuts), and low-fat diets, containing elements of these items.
TAKE HOME:
For clients who wish to reduce the risk of heart disease, a list of the above foods should be provided, where they aim to eat a combination of the foods each day. Dr Jenkins, who has investigated the portfolio diet has noted that he ascribes a 5% of LDL-C reductions to manageable amounts of these 4 components: 50-75 g oat bran diet or 2-3 teaspoons of psyllium; 1-2 g plant sterol (2 g plant sterol is reported to give as much as 10%-15% LDL-C reduction); 25 g soy protein in soy milk, meat analogues, and tofu; and a handful of mixed nuts (42 g, raw or dry roasted).
The effect of cluster loading on force, velocity, and power during ballistic jump squat training
Hansen KT, Cronin JB and Newton MJ
International Journal of Sports Physiology (2011) 6 (4) 455-68
The purpose of this study was to investigate the effect of set structure, in terms of repetition work:rest ratios on force, velocity, and power during jump squat training. Twenty professional and semiprofessional rugby players performed training sessions comprising four sets of 6 repetitions of a jump squat using four different set configurations. The first involved a traditional configuration (TR) of 4 × 6 repetitions with 3 min of rest between sets, the second (C1) 4 × 6 × singles (1 repetition) with 12 s of rest between repetitions, the third (C2) 4 × 3 × doubles (2 repetitions) with 30 s of rest between pairs, and the third (C3) 4 × 2 × triples (3 repetitions) with 60 s of rest between triples. A spreadsheet for the analysis of controlled trials that calculated the P-value, and percent difference and Cohen's effect size from log-transformed data was used to investigate differences in repetition force, velocity, and power profiles among configurations. Peak power was significantly lower (P < .05) for the TR condition when compared with C1 and C3 for repetition 4, and all cluster configurations for repetitions 5 and 6. Peak velocity was significantly lower (P < .05) for the TR condition compared with C3 at repetition 4, significantly
lower compared with C2 and C3 at repetition 5, and significantly lower compared with all cluster conditions for repetition 6. Providing inter-repetition rest during a traditional set of six repetitions can attenuate decreases in power and velocity of movement through the set.
COMMENTS:
Cluster training, also called the Rest-Pause Method, involves the addition of rest periods between reps in a set. A common way of performing this method would be to do a set of 5 repetitions in the deadlift. However, the weight would be set at 3RM and therefore a 5-10 second rest between repetitions would be needed to perform all 5 reps. Traditionally, cluster training has be used to improve th development of strength and power.
This study, performed by Dr Newton and his doctoral student Keir Hanson, compared training sessions where the set x rep x rest configurations were different but matched for equal volume and time: (a) 4 sets of 6 reps, with 3 min of rest between sets, (B) 4 sets of 6 singles (1 repetition) with 12 s of rest between repetitions and 2 min rest between sets, (C) 4 sets of 3 doubles (2 repetitions) with 30 s of
rest between pairs and 2 min between sets, and the (D) 4 sets of 2 triples (3 repetitions) with 60 s of rest between triples and 2 min between sets.
The authors concluded by saying that “ballistic movements are commonly utilized to develop lower-body muscular power in athletic populations. Whereas hypertrophy and strength training adaptation is dependent on mechanical stimuli such as total forces and mechanical work which are likely to induce some level of metabolic fatigue, it is possible that for the development of muscular power during ballistic training, mechanical qualities such as peak velocity and peak power are important (possibly mediating neural adaptations).
Our results have shown that decreases in power and velocity of movement associated with the latter repetitions of a set of jump squats can be reduced by the use of cluster loading configurations. Dividing a traditional set of six repetitions into clusters of either one, two, or three repetitions can attenuate decreases in power and velocity of movement throughout the set. However, the practitioner needs to be aware that, should other mechanical stimuli and associated metabolic responses be important precursors to power development (or be a desired training outcome), a traditional set configuration may represent the more appropriate training prescription."
TAKE HOME:
In another study by the same group, it was found that traditional set/rep structures were superior for gains in strength, whereas cluster training was superior for the development of power (Journal of Strength & Conditioning Research 25(8): 2118–2126, 2011). So, when writing strength workouts for athletes who need high levels of power, consider adding cluster set schemes into their periodized training plans. If the athlete requires relative strength, then traditional maximal strength set/rep methods should be used.
BOOK REVIEW
NSCA's Guide to Program Design
ISBN: 9780736084024. Copyright: 2012. Edition: 1st. Editors: Jay Hoffman, PhD. Speciality: Strength training. Publisher: Human
Kinetics.List price: $53.35
INTRODUCTION:
While there are many books available on weight lifting exercise technique and the physiology/biomechanics of strength training, there is a notable gap in the market on authoritative textbooks devoted to program design for the strength and conditioning professional. The NSCA and Professor Jay Hoffman have assembled a world class team of strength coaches and scientists to address this much needed topic.
DESCRIPTION:
The strength and conditioning profession has evolved over the past three decades from, typically, unpaid ‘help’ to athletes in the weights room to a profession which involves a team of experts, which include sports scientists working with the coaches (and others professionals, such as sports physicians, nutritionists and biomechanists) to understand the principles that underlie performance enhancement. The modern strength coach must now have expertise in a diversity of fields and textbooks written to help the busy coach in the practical application of program design are lacking. This book fills the gap and provides strength and conditioning professionals with a text which addresses all areas needed in the profession with sound scientific evidence behind the practical program design components in each chapter.
PURPOSE:
Most textbooks published in the strength and conditioning field cover exercise technique or the scientific principles of the strength training. Several books written by individual authors cover program design for a single sport or that author’s idiosyncratic approach to program design or lack sound scientific backing. The NSCA Guide to Program Design is a multi-authored volume that features all topics needed to effectively design programs for a number of different sports and energy systems with strong scientific underpinning written by foremost authorities in their respective discipline.
AUDIENCE:
The text is primarily aimed at the strength and conditioning professional. Students in sports science, exercise science and strength and conditioning will benefit from the diversity of topics. Personal trainers and those working in the allied fields to strength and conditioning, such as sports physicians, physiotherapists, psychologists and nutritionists will also find this text useful to understand the science behind and the steps involved in writing successful strength training programs.
FEATURES:
The book includes chapters on all relevant aspects faced by the strength and conditioning coach. Topics include: Athlete needs analysis, athlete testing and program evaluation, dynamic warm-ups, resistance training, power training, anaerobic conditioning, endurance training , agility training, speed training, balance and stability training, training integration and periodization, and training program implementation. Each chapter discusses the scientific foundations to the topic and provides practical application to program design for several different sports.
ASSESSMENT:
The NSCA and Dr Hoffman are to be complimented for providing a book which fills the gap in this under published field and that covers all the major areas in which strength and conditioning coaches must have expertise. Each chapter is authored by world renowned experts in that field. Practical examples of programs for several different sports are provided.
SCORE:
4.5/5
A. E. Jeukendrup and R. Randell
Obesity Reviews (2011) 12, 841–851
The term ‘fat burner’ is used to describe nutrition supplements that are claimed to acutely increase fat metabolism or energy expenditure, impair fat absorption,increase weight loss, increase fat oxidation during exercise, or somehow cause long-term adaptations that promote fat metabolism. Often, these supplements contain a number of ingredients, each with its own proposed mechanism of action and it is often claimed that the combination of these substances will have additive effects. The list of supplements that are claimed to increase or improve fat metabolism is long; the most popular supplements include caffeine, carnitine, green tea, conjugated linoleic acid, forskolin, chromium, kelp and fucoxanthin. In this review the evidence for some of these supplements is briefly summarized. Based on the available literature, caffeine and green tea have data to back up its fat metabolism-enhancing properties. For many other supplements, although some show some promise, evidence is lacking. The list of supplements is industry driven and is likely to grow
COMMENTS:
There are many ways to turn off fat burning: eating too much, exercising too little, high insulin levels, not sleeping enough, stress levels and on and on. Unfortunately, there are not too many ways we can turn on fat burning. The obvious candidates are being physically fit, eating less than we expend and keeping insulin levels low. There are numerous supplements on the market that are promoted as ‘fat burners’. But do they perform as they are advertised and do they really make a difference to a client’s fat loss efforts? Drs Jeukendrup and Randell have performed an up to date examination and review of the supplements that claim to increase fat burning. Of the many that are advertised, only green tea and caffeine have scientific support for their efficacy.
TAKE HOME:
The majority of legal supplements promoted to increase fat burning do not work. Both green tea and caffeine are the exceptions. Save you client’s money, and have them emphasize higher energy expenditure, lower caloric intake, good sleep and stress reduction to maximize fat loss results. This is where the best outcomes are to be found. If you wish to incorporate two scientifically proven ‘helpers’, then you may wish to consider adding green tea (500mg of EGCG) or caffeine (2-4mg per kg of body mass) prior to exercise.
Nutraceutical Supplements for Weight Loss: A Systematic Review
Kavita Poddar, Sanjivani Kolge, Lena Bezman, Gerard E. Mullin, and Lawrence J. Cheskin,
Nutrition in Clinical Practice Volume 26 Number 5October 2011 539-552
In summary, there is a dearth of data on the effect of dietary supplements on body weight loss in humans. Thepublished data to date provide inconclusive evidence on the usefulness of different dietary supplements for weightloss. Caution must be exercised before recommending the use of these supplements for weight loss, as there is evidencethat some may produce harmful effects. When using any of these alternative therapies as adjuncts for weightcontrol, one must remember that, although derived from natural sources, they may nonetheless exhibit powerfulpharmacologic effects and are thus still “medicines.” For example, foxglove, the plant origin of digitalis, has wellknowntoxic effects comparable to those seen with pharmacologic digitalis dosing. Therefore, it is extremely important to use these supplements wisely and in limited amounts.
In closing, it is fitting to highlight that perhaps the most general and safest alternative/herbal approach to weight control is to substitute low-energy density foods for high-energy density and processed foods, thereby reducing total energy intake. By taking advantage of the low-energy density and health-promoting effects of plant-based foods, one may be able to achieve weight loss,or at least assist weight maintenance without cutting down on the volume of food consumed or compromising its nutrient value. Because of the lack of quality, safety, and efficacy of many of the supplements discussed in this article, their use should generally be discouraged. Some supplements (eg, guar gum and chitosan) seem to show no efficacy. Ephedra, although quite effective for weight loss, is very well known for its adverse effects, and products containing even traces of this supplement should be discouraged. Many other supplements lack enough clinical evidence to support their role in weight loss, or studies have resulted in contradictory evidence. These supplements include conjugated linoleic acid, ginseng, glucomannan, green tea, HCA, L-carnitine, and psyllium.
Although data on some supplements are encouraging, they may lack sufficient data or have been evaluated in poorly conducted clinical trials. Further studies are needed to evaluate the effectiveness of “herbal medicines” for weight loss and weight maintenance. Given the fact that conventional weight loss methods are not often effective long term, nonprescription dietary supplements have become popular among those seeking quick results. However, given the generally limited evidence of efficacy, even the smallest undesirable side effect of these supplements can shift the risk-benefit ratio to the unfavorable.
Thus, in conclusion, based on the available science, recommending nonprescription dietary supplements as an adjunct to weight loss currently cannot be stronglyrecommended.
COMMENTS:
This review does an excellent job at pointing out the obvious that has been lost in the personal training industry for sometime: fat loss is best achieved by increasing energy expenditure above energy intake. Any effect of supplements are totally insignificant when compared to the benefits achieved through creating a negative energy balance. This review thoroughly examines all the available literature on supplements promoted as fat loss aids. Only the following had “some evidence” (which really means “much more research is needed before recommending to clients”): Psyllium, Konjac root fiber, Green tea, Cissus quadrangularis, and Citrus aurantium.
TAKE HOME:
Personal trainers and our clients are constantly looking for ways to assist in fat reduction. Many of us utilize supplements to this end. Most of us are not really aware of the level of evidence for the supplements. There are many supplements that have plausible theoretical pathways to aid fat loss. Many are involved in improving insulin sensitivity or have a role in fat oxidative pathways. However, when examined in humans over many months with a placebo group, most supplements have no effect. Every trainer should be able to answer intelligently any questions a client may have on how does the supplement work? And how much extra gain will I expect to see? Answers such as, “this improves insulin sensitivity” or “this increases fat burning” are unacceptable. If we don’t know how much extra gain a client will receive, how the supplement works and what the studies have shown on the supplement (or worse, we are only relying on an internet site or a course we attended which told you how to prescribe supplements based on someone’s body composition) we are doing a great disservice to our clients and wasting their money and this often results in losing credibility. So, save your client’s money. Do our homework and stop prescribing supplements that have limited to no value in helping clients lose fat.
Effects of 4 weight-loss diets differing in fat, protein, and carbohydrate on fat mass, lean mass, visceral adipose tissue, and hepatic fat: results from the POUNDS LOST trial.
de Souza RJ, Bray GA, Carey VJ, Hall KD, Leboff MS, Loria CM, Laranjo NM, Sacks FM, Smith SR.
American Journal of Clinical Nutrition First published ahead of print January 18, 2012 as doi: 10.3945/ajcn.111.026328
Weight loss reduces body fat and lean mass, but whether these changes are influenced by macronutrient composition of the diet is unclear.We determined whether energy-reduced diets that emphasize fat, protein, or carbohydrate differentially reduce total, visceral, or hepatic fat or preserve lean mass.In a subset of participants in a randomized trial of 4 weight-loss diets, body fat and lean mass (n = 424; by using dual-energy X-ray absorptiometry) and abdominal and hepatic fat (n = 165; by using computed tomography) were measured after 6 mo and 2 y. Changes from baseline were compared between assigned amounts of protein (25% compared with 15%) and fat (40% compared with 20%) and across 4 carbohydrate amounts (35% through 65%).At 6 mo, participants lost a mean (±SEM) of 4.2 ± 0.3 kg (12.4%) fat and 2.1 ± 0.3 kg (3.5%) lean mass (both P < 0.0001 compared with baseline values), with no differences between 25% and 15% protein (P ≥ 0.10), 40% and 20% fat (P ≥ 0.34), or 65% and 35% carbohydrate (P ≥ 0.27). Participants lost 2.3 ± 0.2 kg (13.8%) abdominal fat: 1.5 ± 0.2 kg (13.6%) subcutaneous fat and 0.9 ± 0.1 kg (16.1%) visceral fat (all P < 0.0001 compared with baseline values), with no differences between the diets (P ≥ 0.29). Women lost more visceral fat than did men relative to total-body fat loss. Participants regained ∼40% of these losses by 2 y, with no differences between diets (P ≥ 0.23). Weight loss reduced hepatic fat, but there were no differences between groups (P ≥ 0.28). Dietary goals were not fully met; self-reported contrasts were closer to 2% protein, 8% fat, and 14% carbohydrate at 6 mo and 1%, 7%, and 10%, respectively, at 2 y.Participants lost more fat than lean mass after consumption of all diets, with no differences in changes in body composition, abdominal fat, or hepatic fat between assigned macronutrient amounts.
COMMENTS:
In our industry, clients have been often taught to become obsessed with counting grams of carbohydrate. In my younger years, we were obsessed with counting calories and in my parent’s day, it was counting grams of fat. It saddens me to think that so many clients of personal trainers have been taught to avoid carbohydrate because it will make them fat. Worse, many clients – who already may not particularly enjoy exercise – are attempting to perform high intensity weight training or intervals on low carbohydrate diets and because their muscle glycogen stores and blood glucose levels are so low, now find exercise even less appealing and therefore compliance is further reduced.
This study, just published in the prestigious American Journal of Clinical Nutrition, examined diets of differing carbohydrate, fat and protein levels, while keeping calories similar. Professor Marion Nestle has recently commented on the paper and has said that this study “went to a lot of trouble to prove the obvious. When it comes to weight loss, how much you eat matters more than the proportion of fat, carbohydrate, and protein in your foods.”
“Researchers at the Pennington Biomedical Research Center got volunteers to eat diets that were supposed to differ in proportions of fat (40% vs 20%), carbohydrates (35% vs. 65%), and protein (25% vs. 15%). The results of the study are consistent with the findings from many previous studies (1) The major predictor for weight loss was adherence to the diet, (2) People on all of the diets lost weight by six months, but regained some of it by two years. (3) The study had a high drop-out rate (hence the importance of adherence), and (4) It was hard for people to stick to the diets, especially those at the extremes of one dietary component or another."
"Some people find it easier to stick to diets that are higher in protein and fat. I’m guessing that proponents of low-carbohydrate diets will argue that none of the diets in this particular study was really low in carbohydrate."
"But studies show that people have a hard time adhering to diets that are very low in carbohydrate. The low range in this study—35%—is at the lower end of acceptability for many people."
"The bottom line: all diets work if you stick to them." Professor Nestle’s full comments can be found here: http://www.foodpolitics.com/2012/01/want-to-lost-weight-eat-less/
The Impact of Dietary Changes and Dietary Supplements on Lipid Profile: Systematic Review/Meta-analysis
Jingbo Huang, Jiri Frohlich, and Andrew P. Ignaszewski,
Canadian Journal of Cardiology 27 (2011) 488–505
With a growing number of dietary interventions that claim to improve lipid profile, it is important to ensure that these claims are evidence based. The objective of this study was to make recommendations for dietary regimens by analyzing their effectiveness and the level of evidence. We searched MEDLINE as well as the Cochrane Database of Systematic Reviews for nutritional studies. Meta-analyses and randomized controlled trials published in English and including data on the effect on blood lipid levels were used. Randomized controlled trials were included if they were at least 4 weeks in duration and had a minimum of 50 participants. We identified 22 different dietary interventions and reviewed 136 studies published between January 1990 and December 2009 that met our inclusion criteria. Our literature review showed that to improve lipid profile, the following regimens can be recommended fully: Mediterranean and Portfolio diets; low-fat diet; diet high in soy protein, fibre, or phytosterols; whole grain foods, and omega-3 fatty acid supplementation. The consumption of nuts, a diet high in carbohydrates and protein, green tea, and red wine, as well as the supplementation with policosanol and red yeast rice extract, can be considered for improvement of the lipid profile, while the supplements of guggulipid, garlic, chromium, vitamin C, magnesium-pyridoxal-phosphate-glutamate, tocotrienols, and absorbitol cannot be recommended.
COMMENTS:
This is my favourite nutrition paper of 2011. The authors explain that statin medication may reduce LDL-C by up to 60% but only reduce the risk of heart disease by less than 50%, whereas diet and lifestyle changes have shown an 80% reduction in risk of heart disease. Many individual foods and foods in combination ("diet") play an impressive role in heart protection. This study reviews the latest evidence for these foods in heart health and lists the following to be incorporated into a heart disease protection diet: viscous fibres (in oats, barley, and psyllium) and plant sterols but also of soy protein, nuts, red wine, and green tea and the supplements (red yeast rice, omega-3 fatty acids, and polycosanols). The review further supports the use of diets including the Mediterranean, portfolio (combined high fibre, plant sterols, soy and nuts), and low-fat diets, containing elements of these items.
TAKE HOME:
For clients who wish to reduce the risk of heart disease, a list of the above foods should be provided, where they aim to eat a combination of the foods each day. Dr Jenkins, who has investigated the portfolio diet has noted that he ascribes a 5% of LDL-C reductions to manageable amounts of these 4 components: 50-75 g oat bran diet or 2-3 teaspoons of psyllium; 1-2 g plant sterol (2 g plant sterol is reported to give as much as 10%-15% LDL-C reduction); 25 g soy protein in soy milk, meat analogues, and tofu; and a handful of mixed nuts (42 g, raw or dry roasted).
The effect of cluster loading on force, velocity, and power during ballistic jump squat training
Hansen KT, Cronin JB and Newton MJ
International Journal of Sports Physiology (2011) 6 (4) 455-68
The purpose of this study was to investigate the effect of set structure, in terms of repetition work:rest ratios on force, velocity, and power during jump squat training. Twenty professional and semiprofessional rugby players performed training sessions comprising four sets of 6 repetitions of a jump squat using four different set configurations. The first involved a traditional configuration (TR) of 4 × 6 repetitions with 3 min of rest between sets, the second (C1) 4 × 6 × singles (1 repetition) with 12 s of rest between repetitions, the third (C2) 4 × 3 × doubles (2 repetitions) with 30 s of rest between pairs, and the third (C3) 4 × 2 × triples (3 repetitions) with 60 s of rest between triples. A spreadsheet for the analysis of controlled trials that calculated the P-value, and percent difference and Cohen's effect size from log-transformed data was used to investigate differences in repetition force, velocity, and power profiles among configurations. Peak power was significantly lower (P < .05) for the TR condition when compared with C1 and C3 for repetition 4, and all cluster configurations for repetitions 5 and 6. Peak velocity was significantly lower (P < .05) for the TR condition compared with C3 at repetition 4, significantly
lower compared with C2 and C3 at repetition 5, and significantly lower compared with all cluster conditions for repetition 6. Providing inter-repetition rest during a traditional set of six repetitions can attenuate decreases in power and velocity of movement through the set.
COMMENTS:
Cluster training, also called the Rest-Pause Method, involves the addition of rest periods between reps in a set. A common way of performing this method would be to do a set of 5 repetitions in the deadlift. However, the weight would be set at 3RM and therefore a 5-10 second rest between repetitions would be needed to perform all 5 reps. Traditionally, cluster training has be used to improve th development of strength and power.
This study, performed by Dr Newton and his doctoral student Keir Hanson, compared training sessions where the set x rep x rest configurations were different but matched for equal volume and time: (a) 4 sets of 6 reps, with 3 min of rest between sets, (B) 4 sets of 6 singles (1 repetition) with 12 s of rest between repetitions and 2 min rest between sets, (C) 4 sets of 3 doubles (2 repetitions) with 30 s of
rest between pairs and 2 min between sets, and the (D) 4 sets of 2 triples (3 repetitions) with 60 s of rest between triples and 2 min between sets.
The authors concluded by saying that “ballistic movements are commonly utilized to develop lower-body muscular power in athletic populations. Whereas hypertrophy and strength training adaptation is dependent on mechanical stimuli such as total forces and mechanical work which are likely to induce some level of metabolic fatigue, it is possible that for the development of muscular power during ballistic training, mechanical qualities such as peak velocity and peak power are important (possibly mediating neural adaptations).
Our results have shown that decreases in power and velocity of movement associated with the latter repetitions of a set of jump squats can be reduced by the use of cluster loading configurations. Dividing a traditional set of six repetitions into clusters of either one, two, or three repetitions can attenuate decreases in power and velocity of movement throughout the set. However, the practitioner needs to be aware that, should other mechanical stimuli and associated metabolic responses be important precursors to power development (or be a desired training outcome), a traditional set configuration may represent the more appropriate training prescription."
TAKE HOME:
In another study by the same group, it was found that traditional set/rep structures were superior for gains in strength, whereas cluster training was superior for the development of power (Journal of Strength & Conditioning Research 25(8): 2118–2126, 2011). So, when writing strength workouts for athletes who need high levels of power, consider adding cluster set schemes into their periodized training plans. If the athlete requires relative strength, then traditional maximal strength set/rep methods should be used.
BOOK REVIEW
NSCA's Guide to Program Design
ISBN: 9780736084024. Copyright: 2012. Edition: 1st. Editors: Jay Hoffman, PhD. Speciality: Strength training. Publisher: Human
Kinetics.List price: $53.35
INTRODUCTION:
While there are many books available on weight lifting exercise technique and the physiology/biomechanics of strength training, there is a notable gap in the market on authoritative textbooks devoted to program design for the strength and conditioning professional. The NSCA and Professor Jay Hoffman have assembled a world class team of strength coaches and scientists to address this much needed topic.
DESCRIPTION:
The strength and conditioning profession has evolved over the past three decades from, typically, unpaid ‘help’ to athletes in the weights room to a profession which involves a team of experts, which include sports scientists working with the coaches (and others professionals, such as sports physicians, nutritionists and biomechanists) to understand the principles that underlie performance enhancement. The modern strength coach must now have expertise in a diversity of fields and textbooks written to help the busy coach in the practical application of program design are lacking. This book fills the gap and provides strength and conditioning professionals with a text which addresses all areas needed in the profession with sound scientific evidence behind the practical program design components in each chapter.
PURPOSE:
Most textbooks published in the strength and conditioning field cover exercise technique or the scientific principles of the strength training. Several books written by individual authors cover program design for a single sport or that author’s idiosyncratic approach to program design or lack sound scientific backing. The NSCA Guide to Program Design is a multi-authored volume that features all topics needed to effectively design programs for a number of different sports and energy systems with strong scientific underpinning written by foremost authorities in their respective discipline.
AUDIENCE:
The text is primarily aimed at the strength and conditioning professional. Students in sports science, exercise science and strength and conditioning will benefit from the diversity of topics. Personal trainers and those working in the allied fields to strength and conditioning, such as sports physicians, physiotherapists, psychologists and nutritionists will also find this text useful to understand the science behind and the steps involved in writing successful strength training programs.
FEATURES:
The book includes chapters on all relevant aspects faced by the strength and conditioning coach. Topics include: Athlete needs analysis, athlete testing and program evaluation, dynamic warm-ups, resistance training, power training, anaerobic conditioning, endurance training , agility training, speed training, balance and stability training, training integration and periodization, and training program implementation. Each chapter discusses the scientific foundations to the topic and provides practical application to program design for several different sports.
ASSESSMENT:
The NSCA and Dr Hoffman are to be complimented for providing a book which fills the gap in this under published field and that covers all the major areas in which strength and conditioning coaches must have expertise. Each chapter is authored by world renowned experts in that field. Practical examples of programs for several different sports are provided.
SCORE:
4.5/5
