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ERDExamine.comResearch DigestLayne Norton 5 Year Anniversary Edition1
From the EditorFirst, we want to thank you for taking the time to check out theExamine.com Research Digest (ERD). We feel a connection to thosewho love to get their hands dirty, wading through interesting andcomplex topics in nutrition and supplementation.Examine.com was founded five years ago to help cut through themassive amount of misinformation on the web and everywhere else.To make sure we stay unbiased, we have a strict policy of accepting no advertising, sponsorship, product samples, or pretty muchanything else that could even slightly skew our research. There’s areason why over 50,000 people visit us every day.As our reputation grew, health professionals started asking if theycould get continuing education credits from reading our reviews.We responded with ERD, which covers new research in depth,using editors and reviewers from academic fields ranging from neuroscience to immunology. Each month, ERD looks at eight recentpapers that are both interesting and practical, and presents themin an easy-to-read and graphically pleasing manner. We are nowapproved for CECs from NSCA, NASM, The Academy, and more.Layne has always been a big supporter of ERD,so we made this special anniversary issue for hisreaders, containing five ERD articles he thoughtyou would find interesting.For 72 hours only, we are offering ERD at a sale price of 20% off.Click here to buy ERD(on sale only until March 17 midnight EST)Examine.com is THEresource for sciencebased unbiasednutrition andsupplementationrecommendations.It’s the only websitethat I personally goto when I don’t havetime to read andanalyze an entireresearch articlemyself. Examine.comis what I recommendto anyone lookingfor the best scientificnutrition andsupplementationinformation.- Layne NortonClick here to learn more about how Examine.comevolved over the past five years.Kamal Patel, Editor-in-Chief2
Table of Contents05One meal, two meal, three meal, more?16How the Food Industry Spins Science to Fit Its Agenda19Throwdown: plant vs animal protein for metabolic syndromeWhile there’s been a lot of research on meal frequency and dieting, no onehas summarized all the data until now.By Andy Bellatti, MS, RDThe DASH diet is frequently tested in clinical trials, and often performs well.But the diet’s formulation includes strong limitations on red meat, which maybe based on outdated evidence. This study compared animal-protein richdiets with a typical DASH diet.28Investigating slow carbs for metabolic rate36Sugar Wars, Episode 2: “Fructose Strikes Back”Glycemic index, glycemic load, insulin index: only one of these is widelyknown by the public. But when it comes to keeping weight off, does glycemicindex and total carb content actually have any impact?Few food components have been demonized as much as fructose in thepast decade. With fructose being presumed guilty in metabolic syndromeand heart disease, this systematic review sheds light on it’s actual impact onblood lipids.3
ContributorsResearchersMargaret WertheimM.S., RDAlex LeafM.S(c)Courtney Silverthorn Zach BohannanPh.D.M.S.Anders NedergaardPh.D.Jeff RothschildM.Sc., RDKatherine RizzoneM.D.Spencer NadolskyD.O.Greg PalcziewskiPh.D. (c)EditorsGregory LopezPharm.D.ReviewersPablo Sanchez Soria Kamal PatelPh.D.M.B.A., M.P.H.,Ph.D(c)Arya SharmaPh.D., M.D.Natalie MuthM.D., M.P.H., RDStephan GuyenetPh.D.Mark KernPh.D., RDGillian MandichPh.D(c)Adel MoussaPh.D(c)Sarah BallantynePh.D.4
One meal, two meal,three meal, more?Effects of meal frequency on weightloss and body composition: a metaanalysisIntroductionThe first law of thermodynamics states that energy is not created or destroyed, but rather, it changesform. In the world of body weight regulation, this translates roughly to calories in vs. calories out,signifying that changes in body weight are dependent on imbalances between the amount of energyentering the body and the amount of energy leaving the body. There is no doubt that one must maintain a caloric deficit to lose weight, but to stop there would only scratch the surface.Various nutritional and environmental factors can influence energy storage or expenditure within the5
context of the first law of thermodynamics. For instance,of interest, as well as the ability to identify patterns, discrep-resistance training can help partition a portion of excessancies, and relationships between the included studies. Incalories toward muscle growth rather than fat storage.order to be included in the current meta-analysis, the stud-Consumption of protein is not only necessary for muscleies were required to meet five inclusion criteria:growth, it is also more thermogenic than carbohydrates orfats. Moreover, intense exercise attenuates the detrimentalmetabolic effects of overfeeding, and also leads to greater fatloss when compared to no exercise.1. Had to be a randomized controlled trial (RCT) published in English2. Had to compare unequal feeding frequencies of lessthan three meals per day with more than three mealsAnother suggested method of optimizing body composi-per daytion outcomes is meal frequency. The idea that eating small,frequent meals enhances fat loss and aids in weight management dates back to the classic skinfold thickness data of379 Czechoslovakian men published in The Lancet in 1964.Since then, observational data has supported the relationship between eating frequency and obesity risk. Proposedmechanisms for the benefits include appetite regulation,improved glucose tolerance, and the thermic effect of themeals. Additionally, increased meal frequency has beenshown to play a crucial role in the anabolic responses toresistance training.Despite an apparent theoretical basis, studies assessing therelationship between meal frequency and body compositionhave conflicting results, perhaps from differences in thestudy populations and procedures. Thus, the current studywas a meta-analysis aimed at pooling the outcomes of thesestudies to clarify on the relationship between meal frequency and changes in fat mass and lean body mass.There have been many studies done to determine theeffect of meal frequency of weight managment. The studyunder review is a meta-analysis, meaning researcherspooled data from previous studies to determine correlation and other relationships.Who and what was studied?No one was studied, per se. Instead, the data from existingstudies was gathered and included in several meta-analyses.[.] studiesassessing therelationshipbetween mealfrequencyand bodycompositionhave conflictingresults, perhapsfrom differencesin the studypopulations andprocedures.This allows for greater statistical power to detect outcomes6
3. Had a study duration of at least two weeksThus, each outcome had essentially three meta-analyses, the4. Reported a pre- and post-measure of body compositionsimple continuous (e.g., for each additional meal/day), the5. Used human subjects over 18 years of agereduced binary, and the reduced categorical.As we can see from the five criteria, there was a lot of wig-The reduced models generated by the researchers were thengle-room for study procedures. What measures of bodysubject to permutation testing. Each study included in thecomposition were used? Were the unequal feedings calo-analysis was removed one at a time and the outcomes wererie-controlled? Was protein equal? Were the subjects young,re-calculated. This method allows the researchers to identifyold, overweight, or normal weight? Nonetheless, a search ofhighly influential studies that may have skewed the results.the literature for all studies from the beginning of time toNovember 2013 ultimately yielded 15 studies to include inthe analysis.This study analyzed the findings from 15 studies. Studieshad to meet five criteria to be eligible for inclusion, whichA meta-analysis for each measure of body compositionwas created in which the number of meals per day was theincluded a human subjects requirement and a study duration of at least two weeks.only experimental variable. Since meal frequency outcomescan be affected by numerous other factors such as initialbody mass of the participants, caloric intake, and actualnumber of meals, a reduced meta-analysis was created thatcontrolled for these factors. These reduced analyses werethen used to generate outcomes when meal frequency wascategorical (1-2, 3-4, 5 meals) or binary (high vs. low).What were the findings?Understanding the basics of the studies included in themeta-analysis is important to contextualize the outcome.Figure 1 summarizes some important study characteristics. Most of the studies used participants who were underFigure 1: Study characteristics7
49 years old, overweight or obese, and sedentary, with noan average of 0.89 kilograms more fat loss than lower mealexercise added to the trial. Also, seven of the studies werefrequencies, with more than five meals resulting in 1.24less than four weeks in duration, with only four studieskilograms more fat loss than one to two meals. But theselasting longer than 12 weeks. The inherent limitations of theresults also became not significant after the permutationincluded studies translate directly to the meta-analysis andtest. Under no circumstances were the differences betweenwill thus greatly limit the generalizability of the results to,one to two and three to four meals or three to four andfor example, the elderly or lean athletes.more than five meals statistically significant.Meal frequency was not significantly associated withThe reason people imply fat loss when they say ‘diet ischanges in body weight. However, body weight is a crudebecause they want to preserve any and all lean body massoutcome when it comes to dieting because it fails to account(LBM) they have. Unfortunately, the outcomes for preserva-for changes in body composition.tion of LBM follow the same path as the outcomes for bodyfat. There was a trend for more meals to preserve more LBMMost people imply fat loss when they discuss weight loss. In( 0.22 kilograms with each additional meal) that becamethis regard, the simple meta-analysis (with results shown innowhere near significant when the same study that impact-Figure 2) did find a statistically significant reduction of 0.25ed the fat mass outcomes was removed (p 0.07 p 0.96).kilograms of fat mass with each additional meal. But remov-The only reduced model to show a significant difference wasal of a single study (Iwao, et al) from the analysis made thismore than five meals vs. one to two meals per day, and thisfinding not significant (p 0.04 p 0.44). Additionally, inwas not supported by the permutation test results.the reduced models, higher meal frequencies resulted inFigure 2: Meal Frequency effect on fat mass, by study8
The boxerstudy was theonly studyincluded in themeta-analysisthat looked atathletes.Although outcomes for body weight, fat mass, and LBMwere not significant in any regard, there still exists apossibility that their interaction in the form of body fatpercentage could be. Indeed, for each additional meal therewas a significant reduction of 0.23%. But just as with theother outcomes, removal of a single study made this outcome not significant. Even with the study remaining in thedata set, the significance disappeared when other covariateswere controlled for in the reduced models, and the permutation test also failed to support a significant finding.in fat mass with greater preservation of LBM as the numberof meals consumed increased. However, these outcomeswere highly influenced by a single study, the removal ofwhich rendered the results not significant. Moreover, themagnitude of the outcomes was so small that any possiblebenefits may have limited practical relevance.It is worth digging into the influential study to determinewhy it would have such a profound impact. This studyfound that boxers consuming six meals per day lost lessLBM and showed lower measures of muscle catabolismthan boxers consuming the same diet in two meals perday. While we should applaud the fact that the diets wereotherwise matched between the groups, its intrinsic designlimitations reduce its relevance.Aside from the short study duration (two weeks) and smallsample size (12 men, no women), energy and protein intakewas incredibly low at 1200 kcal and 60 grams (one gram perkilogram) per day, respectively. To emphasize how minorthese values are, previous research has shown that even 2.3grams per kilogram of protein with over 2,000 kcal per daycannot fully offset the loss of LBM in a dieting athlete. Insuch catabolic circumstances, it is not entirely surprising thateating more frequently would lead to greater LBM retention.Once the above study was removed from the analysis, mealfrequency was found to had no influence on body compo-Body fat percentage, fat mass, and lean body mass at firstappeared to change significantly based on meal frequency, with each additional daily meal associated with a0.23% reduction in body fat. By removing a single studyfrom the analysis, however, the statistical significancedisappeared.sition. However, these results are limited to the populationsused to generate them. That is, overweight and obese sedentary individuals. The boxer study was the only studyincluded in the meta-analysis that looked at athletes.With this in mind, it is important to look at yet anotherstudy that was highly influential in the significant outcomefavoring body fat percentage reductions with increasingWhat does the study really tellus?meal frequency. In this study, 28 middle-aged, sedentary,obese adults (85% women) underwent a four-week weightmaintenance phase followed by a four-week dieting phaseOn the surface, the results appear to favor eating more fre-in one of three groups consuming 25% less kcal than need-quently, as the meta-analyses found significant reductionsed to maintain weight, which was roughly a 500 kcal daily9
deficit. The three groups were two high-pr
Layne Norton 5 Year . resistance training can help partition a portion of excess calories toward muscle growth rather than fat storage. Consumption of protein is not only necessary for muscle growth, it is also more thermogenic than carbohydrates or fats. Moreover, intense exercise attenuates the detrimental metabolic effects of overfeeding, and also leads to greater fat loss when compared .
