Studies on RMR/ Metabolism

[Emma-Leigh]

Family Practice Vol. 16, No. 2, 196-201
© Oxford University Press 1999

Effects of dieting and exercise on resting metabolic rate and implications for weight management

Josephine Connolly, Theresa Romano and Marisa Patruno
Department of Family Medicine, University Hospital and Medical Center, SUNY Stony Brook, Stony Brook, New York 11794-8461, USA.

Received 13 August 1998; Accepted 19 November 1998.

Introduction

The significance of the rising prevalence of obesity for morbidity and associated health care costs is clearly delineated by the United States National Institutes of Health's Clinical Guidelines on the Identification, Evaluation and Treatment of Overweight and Obesity in Adults.1 The guidelines note the following: 55% of the adult population in the United States is overweight or obese, obesity is the second leading cause of preventable death after smoking in the United States, and the total cost to society attributable to obesity-related diseases approaching 100 billion US dollars annually. The expert panel that developed the guidelines, which are available on the World Wide Web (http://www.nhlbi.nih.gov/nhlbi/), define overweight as a body mass index (weight, kilograms/[height, meters]2) of 25 to 29.9 and obesity as a body mass index of 30 and above. Many countries use this criterion. The guidelines recommend weight loss to lower blood pressure, to lower high total cholesterol, to raise low levels of HDL and to lower elevated blood glucose. Calorie reduction, increased physical activity and behaviour therapy are recommended as the first-line treatment for obesity, with consideration of pharmacological therapies as a secondary alternative.

Despite years of research, the treatment of obesity continues to revolve around the seemingly simple concept of balancing calorie expenditure with calorie intake. However, the determinants of energy expenditure, specifically resting metabolic rate, are an active area of research with many debatable issues. This review will address the calorie expenditure side of the scale, with the examination of the effect of dieting and exercise on resting metabolic rate. Resting metabolic rate accounts for 60–75% of total energy expenditure in sedentary people.2 Therefore, it is a major determinant of energy balance and changes in weight. Factors which decrease resting metabolic rate would be associated with difficulty maintaining weight or weight loss, or frank weight gain. On the contrary, anything that increases resting metabolic rate would facilitate weight loss and maintenance of weight loss. Caloric restriction is known to produce a short-term reduction in resting metabolic rate. Issues that have not been resolved regarding such a reduction are as follows: is the reduction proportional to the reduction in body size or the degree of energy deficit, is the reduction permanent or self-limiting, and can exercise prevent the reduction? If this reduction is a permanent reduction in resting metabolic rate, and if it is above and beyond what would be predicted by the resulting smaller body size, then weight loss after calorie restriction will be very difficult to maintain. This paper reviews four articles that address these issues, three reports of primary research and one meta-analysis. Concluding remarks follow regarding actions that primary care physicians can take in the assessment and treatment of obesity.

Kraemer WJ, Volek JS, Clark KL et al. Physiological adaptations to a weight-loss dietary regimen and exercise programs in women. J Appl Physiol 1997; 83: 270–279.

[Emma-Leigh]

Journal of Parenteral and Enteral Nutrition, Vol. 31, No. 3, 217-227 (2007)
DOI: 10.1177/0148607107031003217

Predicting Energy Expenditure in Extremely Obese Women

Jennifer R. Dobratz, MS*
Shalamar D. Sibley, MD, MPH
Tiffany R. Beckman, MD, MPH
Bret J. Valentine, BS*
Todd A. Kellogg, MD
Sayeed Ikramuddin, MD
Carrie P. Earthman, PhD, RD*
From the * Department of Food Science and Nutrition, Department of Medicine, Endocrine Division, and Department of Surgery, University of Minnesota, St. Paul, Minnesota

Correspondence: Carrie P. Earthman, PhD, RD, Department of Food Science and Nutrition, University of Minnesota, 225 Food Science & Nutrition, University of Minnesota, 1334 Eckles Avenue, St. Paul, MN 55108-6099. Electronic mail may be sent to cearthma@umn.edu.

Background: The most common clinical method for resting energy expenditure (REE) assessment is prediction equations. The purpose of this study was to elucidate which prediction equation is most accurate for REE assessment in extremely obese women. Methods: Fourteen extremely obese women (mean ± SD body mass index: 49.8 ± 6.2 kg/m2; age: 49 ± 10 years) were measured for height and weight and REE via indirect calorimetry (IC) by a metabolic cart system. Predicted REE was evaluated by several equations, including Harris-Benedict with actual body weight, Harris-Benedict with several adjustments to body weight, Cunningham, Mifflin-St Jeor, Owen, World Health Organization (WHO), and Bernstein equations. Accuracy was determined by mean difference data (IC REE – equation REE; Student's paired t-test), correlation coefficients, and agreement between methods by Bland-Altman plots. Accuracy was also evaluated on an individual basis, defined by the percentage of individuals within ±10% of IC REE. Results: The Mifflin-St Jeor, Harris-Benedict with actual body weight, and the WHO equations were the most accurate in terms of mean predicted REE. The mean predicted REE values by all other equations were different from the IC REE values (p < .1). According to the individual data, the Mifflin-St Jeor was most accurate (14% outside ±10% IC REE). The Harris-Benedict with actual body weight and WHO equations were less accurate on individual terms, with 29% and 42% of the predicted REE values, respectively, falling outside ±10% of IC REE. Conclusions: The Mifflin-St Jeor equation was most accurate method for REE assessment in extremely obese women.

[Emma-Leigh]

American Journal of Clinical Nutrition, Vol. 88, No. 4, 959-970, October 2008
© 2008 American Society for Nutrition
ORIGINAL RESEARCH COMMUNICATION

Validity of predictive equations for resting energy expenditure in US and Dutch overweight and obese class I and II adults aged 18–65 y1,2,3

Peter JM Weijs
1 From the Department of Nutrition and Dietetics, Hogeschool van Amsterdam, University of Applied Science, and the Department of Nutrition and Dietetics, VU University Medical Center, Amsterdam, Netherlands

Background: Individual energy requirements of overweight and obese adults can often not be measured by indirect calorimetry.

Objective: The objective was to analyze which resting energy expenditure (REE) predictive equation was the best alternative to indirect calorimetry in US and Dutch adults aged 18–65 y with a body mass index (in kg/m2) of 25 to 40.

Design: Predictive equations based on weight, height, sex, age, fat-free mass, and fat mass were tested. REE in Dutch adults was measured with indirect calorimetry, and published data from the Institute of Medicine were used for US adults. The accuracy of the equations was evaluated on the basis of the percentage of subjects predicted within 10% of the REE measured, the root mean squared prediction error (RMSE), and the mean percentage difference (bias) between predicted and measured REE.

Results: Twenty-seven predictive equations (9 of which were based on FFM) were included. Validation was based on 180 women and 158 men from the United States and on 154 women and 54 men from the Netherlands aged <65 y with a body mass index (in kg/m2) of 25 to 40. Most accurate and precise for the US adults was the Mifflin equation (prediction accuracy: 79%; bias: –1.0%; RMSE: 136 kcal/d), for overweight Dutch adults was the FAO/WHO/UNU weight equation (prediction accuracy: 68%; bias: –2.5%; RMSE: 178), and for obese Dutch adults was the Lazzer equation (prediction accuracy: 69%; bias: –3.0%; RMSE: 215 kcal/d).

Conclusions: For US adults aged 18–65 y with a body mass index of 25 to 40, the REE can best be estimated with the Mifflin equation. For overweight and obese Dutch adults, there appears to be no accurate equation.

[Emma-Leigh]

J Appl Physiol 84: 1333-1340, 1998;


Energy metabolism in sedentary and active 49- to 70-yr-old women

R. T. Withers1, D. A. Smith1, R. C. Tucker1, M. Brinkman2, and D. G. Clark2
1 Exercise Physiology Laboratory, School of Education, The Flinders University of South Australia, Bedford Park, South Australia 5042; and 2 Energy Metabolism Laboratory, Commonwealth Scientific and Industrial Research Organization, Division of Human Nutrition, Adelaide, South Australia 5000, Australia

This study examined differences between long-term exercising (LE) and long-term nonexercising (LNE) women [n = 24; age 56.4 ± 6.2 (SD) yr] for resting metabolic rate (RMR) and energy expenditure in the free-living state by using doubly labeled water (DLW). There was a statistically significant difference (P = 0.0002) between the 12 LE (94.85 ± 8.44 kJ · kg1 · day1) and 12 LNE (81.16 ± 6.62 kJ · kg1 · day1) for RMR, but this difference was only marginally significant (P = 0.06) when the data (MJ/day) were subjected to an analysis of covariance with fat-free mass as the covariate. The DLW data indicated that the eight most active LE (12.99 ± 3.58 MJ/day) expended significantly (P = 0.01) more energy than did the eight least active LNE (9.30 ± 1.15 MJ/day). Energy expenditures ranged from 7.64 to 18.15 MJ/day, but there was no difference (P = 0.96) between the LE and LNE in energy expenditure during activity that was not designed to either improve or maintain fitness. These cross-sectional data on 49- to 70-yr-old women therefore suggest that 1) aerobic-type training results in a greater RMR per unit of body mass and also when statistical control is exerted for the effect of the metabolically active fat-free mass, 2) there is a large range in the energy intake necessary to maintain energy balance, and 3) aerobic training does not result in a compensatory reduction in energy expenditure during the remainder of the day.

resting metabolic rate; doubly labeled water

[Emma-Leigh]

The Journal of Clinical Endocrinology & Metabolism Vol. 87, No. 3 1004-1009
Copyright © 2002 by The Endocrine Society
Endocrine Care

Effects of Endurance and Resistance Training on Total Daily Energy Expenditure in Young Women: A Controlled Randomized Trial

Eric T. Poehlman, Walter F. Denino, Travis Beckett, Kristen A. Kinaman, Isabelle J. Dionne, Roman Dvorak and Philip A. Ades
Divisions of Clinical Pharmacology and Metabolic Research and Cardiology, Department of Medicine, University of Vermont, Burlington, Vermont 05405

Address all correspondence and requests for reprints to: Eric T. Poehlman, Ph.D., Unité Métabolique, Département de Nutrition, Faculté de Médecine, Université de Montréal, 2404 Chemin de la Côte Ste Catherine, Pavillon Lilian de Stewart, Montréal, Québec, Canada H3T 1A8. E-mail: . Eric.Poehlman@Umontreal.CA

Abstract

There exists considerable controversy regarding the impact of different modes of exercise training on total daily energy expenditure (TEE). To examine this question, young, nonobese women were randomly assigned to a supervised 6-month program of endurance training, resistance training, or control condition. TEE was measured before and 10 d after a 6-month exercise program was completed with doubly labeled water. Body composition was determined from dual energy x-ray absorptiometry, maximum aerobic capacity from a treadmill test to exhaustion, and muscular strength from one-repetition maximum tests. Results showed that body composition did not change in endurance-trained women, but maximum aerobic capacity increased by 18%. Resistance-trained women increased muscular strength and fat-free mass (1.3 kg). TEE did not significantly change when measured subsequent to the endurance or resistance training programs. Absolute resting metabolic rate increased in resistance-trained women but not when adjusted for fat-free mass. No change in physical activity energy expenditure was found in any of the groups. These results suggest that endurance and resistance training does not chronically alter TEE in free-living young women. Thus, the energy-enhancing benefits of exercise training are primarily derived from the direct energy cost of exercise and not from a chronic elevation in daily energy expenditure in young, nonobese women.

[Emma-Leigh]

Endocrine Reviews 26 (1): 114-146
Copyright © 2005 by The Endocrine Society


Endocrine Control of Body Composition in Infancy, Childhood, and Puberty

Johannes D. Veldhuis, James N. Roemmich, Erick J. Richmond, Alan D. Rogol, Jennifer C. Lovejoy, Melinda Sheffield-Moore, Nelly Mauras and Cyril Y. Bowers
Division of Endocrinology and Metabolism (J.D.V.), Department of Internal Medicine, Mayo Medical and Graduate Schools of Medicine, General Clinical Research Center, Mayo Clinic, Rochester, Minnesota 55905; Department of Pediatrics (J.N.R.), State University of New York at Buffalo, Buffalo, New York 14214-3000; Departments of Pediatrics and Internal Medicine (E.J.R., A.D.R.), General Clinical Research Center, University of Virginia School of Medicine, Charlottesville, Virginia 22903; Pennington Biomedical Research Center (J.C.L.), Baton Rouge, Louisiana 70808; Division of Endocrinology (M.S.-M.), Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555; Department of Pediatrics (N.M.), Nemours Children’s Clinic, Jacksonville, Florida 32207; and Division of Endocrinology and Metabolism (C.Y.B.), Department of Internal Medicine, Tulane University Medical Center, New Orleans, Louisiana 70112

Correspondence: Address all correspondence and requests for reprints to: Johannes D. Veldhuis, M.D., Division of Endocrinology and Metabolism, Department of Internal Medicine, Mayo Medical and Graduate Schools of Medicine, General Clinical Research Center, Mayo Clinic, Rochester, Minnesota 55905. E-mail: veldhuis.johannes@mayo.edu

Body composition exhibits marked variations across the early human lifetime. The precise physiological mechanisms that drive such developmental adaptations are difficult to establish. This clinical challenge reflects an array of potentially confounding factors, such as marked intersubject differences in tissue compartments; the incremental nature of longitudinal intrasubject variations in body composition; technical limitations in quantitating the unobserved mass of mineral, fat, water, and muscle ad seriatim; and the multifold contributions of genetic, dietary, environmental, hormonal, nutritional, and behavioral signals to physical and sexual maturation. From an endocrine perspective (reviewed here), gonadal sex steroids and GH/IGF-I constitute prime determinants of evolving body composition. The present critical review examines hormonal regulation of body composition in infancy, childhood, and puberty.

[Emma-Leigh]

J Gerontol A Biol Sci Med Sci (2006) 61 (5): 466-473.

The Endeavor of High Maintenance Homeostasis: Resting Metabolic Rate and the Legacy of Longevity
Carmelinda Ruggiero and Luigi Ferrucci1
+ Author Affiliations

1Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
2Institute of Gerontology and Geriatrics, University of Perugia Medical School, Department of Clinical and Experimental Medicine, Italy.
Address correspondence to Carmelinda Ruggiero, MD, NIA, NIH, Harbor Hospital, 5th Floor, 3001 S. Hanover St., Baltimore, MD 21225. E-mail: ruggieroc@grc.nia.nih.gov
Abstract

Metabolism, the continuous conversion between structural molecules and energy, is life in essence. Size, metabolic rate, and maximum life span appear to be inextricably interconnected in all biological organisms and almost follow a “universal” law. The notion of metabolic rate as the natural “rate of living” filled most of the academic discussion on aging in the early 20th century to be later replaced by the free-radical theory of aging. We argue that the rate of living theory was discarded too quickly and that studying factors affecting resting metabolic rate during the aging process may provide great insight into the core mechanisms explaining differential longevity between individuals, and possibly the process leading to frailty. We predict that measures of resting metabolic rate will be introduced in geriatric clinical practice to gather information on the degree of multisystem dysregulation, exhaustion of energy reserve, and risk of irreversible frailty.

[Please see the Editors' Note in the March issue of the Journal (p.259) for a description of the article type "Green Banana."]

[Emma-Leigh]

Rev Bras Med Esporte vol.10 no.2 Niterói Mar./Apr. 2004
doi: 10.1590/S1517-86922004000200006

REVIEW ARTICLE
Acute effects of resistance exercise on energy expenditure: revisiting the impact of the training variables

Efectos agudos de la actividad contra resistencia sobre el costo energético: revisión del impacto de las principales variables
Cláudia de Mello MeirellesI, II, III; Paulo Sergio Chagas GomesI, IV

IHealth Interdisciplinary Research Center - Gama Filho University
IINutrition Department from the Bennett Methodist Institute - Rio de Janeiro, RJ, Brazil
IIINutrition Department from the Gama Filho University - Rio de Janeiro, RJ, Brazil
IVPhysical Education Department from the Gama Filho University


ABSTRACT
The prevalence of obese and overweight persons is growing, both in Brazil and in other parts of the world. It is, therefore, important to establish strategies that will try to control this. The combination of energy restriction and aerobic exercises has long been recognized as an effective means of controlling body composition; on the other hand, the impact of resistance exercises on weight loss is still questionable. Thus, the purpose of this review was to discuss the effect of resistance exercises on energy expenditure, considering each of its related variables - intensity, duration, number of sets, interval between sets, movement velocity and type of training (circuit or multiple sets). The reviewed studies showed that resistance exercises may induce an acute increase in energy expenditure, through the energy cost of the exercise session itself and through the excess post-exercise oxygen consumption (EPOC). It is also recognized that the many variables related to resistance exercises influence the results in different ways. Number of repetitions, load, rest interval between sets and number of sets, when manipulated in order to increase volume or intensity, may significantly increase the energy expenditure of a typical exercise session. In general, considering all the limitations of the reviewed studies, the literature indicates that volume is the variable with greatest impact on energy expenditure during the training session, and that intensity has its largest impact on EPOC.

Key words: Calories. Indirect calorimetry. EPOC. Overweight. Exercise. Obesity.

[Emma-Leigh]

Metabolism
Volume 58, Issue 9, September 2009, Pages 1320-1328
doi:10.1016/j.metabol.2009.04.016 | How to Cite or Link Using DOI
Copyright © 2009 Elsevier Inc. All rights reserved.


Individual responsiveness to exercise-induced fat loss is associated with change in resting substrate utilization
[Sponsored Article]
Nicholas D. Barwella, Dalia Malkovab, Melanie Leggatea and Jason M.R. Gilla, ,

aIntegrative and Systems Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
bDivision of Developmental Medicine, University of Glasgow, United Kingdom
Received 26 February 2009; accepted 24 April 2009. Available online 18 June 2009.
Abstract
Fat loss in response to exercise training varies between individuals, even when differences in compliance to the exercise program are accounted for. The purpose of this study was to investigate whether individual variation in change in fasting respiratory quotient (RQ) after exercise training contributes to this interindividual variability. Fifty-five premenopausal women participated in a 7-week endurance-type exercise training program; and fitness, body composition, and resting substrate utilization and metabolic rate in the fasted state were assessed at baseline and postintervention. Total net energy expenditure of the exercise intervention (exEE) was determined from heart rate obtained in all exercise sessions and individualized calibration of the heart rate vs oxygen uptake relationship. Dietary intake and physical activity (by constant heart rate monitoring) were assessed at baseline and during the final week of the intervention. Mean change in fat mass for the group was −0.97 kg (range, +2.1 to −5.3 kg). The strongest correlate of change in fat mass was exEE (r = 0.60, P < .0005). Change in fasting RQ correlated significantly (r = −0.26, P = .05) with the residual for change in fat mass after adjusting for the effects of both exEE and change in energy intake, explaining 7% of the variance. In multiple regression analysis, exEE (P < .0005) and change in fasting RQ (P = .02) were the only statistically significant independent predictors of change in fat mass, together explaining 40.2% of the variance. Thus, fat loss in response to exercise training depends not only on exercise energy expenditure but also on exercise training–induced changes in RQ at rest. This suggests that development of strategies to maximize the change in resting fat oxidation in response to an exercise training program may help individuals to maximize exercise-induced fat loss.

[Emma-Leigh]

Damn teenage boys:

Am J Clin Nutr (May 26, 2010). doi:10.3945/ajcn.2010.29383

Puberty and observed energy intake: boy, can they eat!1,2,3,4
Lauren B Shomaker, Marian Tanofsky-Kraff, David M Savastano, Merel Kozlosky, Kelli M Columbo, Laura E Wolkoff, Jaclyn M Zocca, Sheila M Brady, Susan Z Yanovski, Melissa K Crocker, Asem Ali and Jack A Yanovski
1 From the Unit on GrowthObesity Program in Developmental EndocrinologyGenetics Eunice Kennedy Shriver National Institute of Child HealthHuman Development National Institutes of Health (NIH) Department of HealthHuman Services Bethesda MD (LBS MT-K DMS KMC LEW JMZ SMB SZY MKC AAJAY); the Department of MedicalClinical Psychology Uniformed Services University of the Health Sciences Bethesda MD (LBS MT-K KMCLEW); the Nutrition Department Clinical Center NIH Bethesda MD (MK);the Division of Digestive DiseasesNutrition National Institute of DiabetesDigestiveKidney Diseases NIH Bethesda MD (SZY).

2 LBS and MT-K contributed equally to this work.

3 Supported by NIH Intramural Research Program grant Z01-HD-00641 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) with supplemental funding from the National Center on Minority Health and Health Disparities and the Office of Behavioral and Social Sciences Research (JAY); grant R072IC from the Uniformed Services University of the Health Sciences and grant 1R01DK080906 from the National Institute of Diabetes and Digestive and Kidney Diseases (MT-K); and National Research Service Award 1F32HD056762 from NICHD (LBS).

4 Address correspondence to JA Yanovski, Unit on Growth and Obesity, NICHD, NIH, 9000 Rockville Pike, Hatfield Clinical Research Center, Room 1E-3330, MSC 1103, Bethesda, MD 20892-1103. E-mail: jy15i@nih.gov.

ABSTRACT

Background: Anecdotal reports suggest that adolescent males consume large quantities of food to meet the growth demands of pubertal development. However, limited experimental data exist to support this impression.

Objective: The objective was to measure energy intakes of youth at different pubertal stages.

Design: Participants were 204 volunteers (50.5% male) aged 8–17 y. Pubertal development was categorized by physical examination into prepuberty (males: testes < 4 mL; females: Tanner breast stage 1), early–midpuberty (males: testes = 4–12 mL; females: Tanner breast stages 2–3), or late puberty (males: testes >12 mL; females: Tanner breast stages 4–5). Energy intake was measured as consumption from a 9835-kcal food array during 2 lunchtime meals.

Results: Males consumed more energy than did females across all pubertal stages (P < 0.001). Intake increased with pubertal development (P < 0.001), but the timing and magnitude of change varied by sex (P = 0.02). Males’ unadjusted energy intake was greater in late puberty (mean ± SE: 1955 ± 70 kcal) than in prepuberty (1287 ± 90 kcal) or early–midpuberty (1413 ± 92 kcal) (P < 0.001). Females’ unadjusted energy intake tended to be lower among prepubertal girls (905 ± 140 kcal) than among females in early–midpuberty (1278 ± 82 kcal, P = 0.07) or late puberty (1388 ± 68 kcal, P = 0.01). After adjustment for fat-free mass, fat mass, height, overweight status, race, and meal instruction, the main effect of sex (P < 0.001) remained significant, but the effect of puberty was not significant (P = 0.66).

Conclusions: The observed intake patterns are congruent with known sexual dimorphisms for body composition, peak growth velocity, and pubertal development. Consistent with their higher energy requirements, males can consume significantly larger amounts of food than females, especially during later puberty. This trial was registered at clinicaltrials.gov as NCT00320177.

Received for publication February 16, 2010. Accepted for publication April 21, 2010.

[Emma-Leigh]

PLoS Hub for Clinical Trials
http://www.plosone.org/article/info%...l.pone.0004377

Metabolic and Behavioral Compensations in Response to Caloric Restriction: Implications for the Maintenance of Weight Loss
Leanne M. Redman, Leonie K. Heilbronn¤a, Corby K. Martin, Lilian de Jonge, Donald A. Williamson, James P. Delany¤b, Eric Ravussin*, for the Pennington CALERIE team
Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America

Background
Metabolic and behavioral adaptations to caloric restriction (CR) in free-living conditions have not yet been objectively measured.

Methodology and Principal Findings
Forty-eight (36.8±1.0 y), overweight (BMI 27.8±0.7 kg/m2) participants were randomized to four groups for 6-months; Control: energy intake at 100% of energy requirements; CR: 25% calorie restriction; CR+EX: 12.5% CR plus 12.5% increase in energy expenditure by structured exercise; LCD: low calorie diet (890 kcal/d) until 15% weight reduction followed by weight maintenance. Body composition (DXA) and total daily energy expenditure (TDEE) over 14-days by doubly labeled water (DLW) and activity related energy activity (AREE) were measured after 3 (M3) and 6 (M6) months of intervention. Weight changes at M6 were −1.0±1.1% (Control), −10.4±0.9% (CR), −10.0±0.8% (CR+EX) and −13.9±0.8% (LCD). At M3, absolute TDEE was significantly reduced in CR (−454±76 kcal/d) and LCD (−633±66 kcal/d) but not in CR+EX or controls. At M6 the reduction in TDEE remained lower than baseline in CR (−316±118 kcal/d) and LCD (−389±124 kcal/d) but reached significance only when CR and LCD were combined (−351±83 kcal/d). In response to caloric restriction (CR/LCD combined), TDEE adjusted for body composition, was significantly lower by −431±51 and −240±83 kcal/d at M3 and M6, respectively, indicating a metabolic adaptation. Likewise, physical activity (TDEE adjusted for sleeping metabolic rate) was significantly reduced from baseline at both time points. For control and CR+EX, adjusted TDEE (body composition or sleeping metabolic rate) was not changed at either M3 or M6.

Conclusions
For the first time we show that in free-living conditions, CR results in a metabolic adaptation and a behavioral adaptation with decreased physical activity levels. These data also suggest potential mechanisms by which CR causes large inter-individual variability in the rates of weight loss and how exercise may influence weight loss and weight loss maintenance.

Trial Registration
ClinicalTrials.gov NCT00099151

[tubalard]

Thanks for this one Emma...

Sounds scary initially, but 6% on top of body proportional changes isn't really that horrendous (e.g. for a 1600 calorie maintenance level, this metabolic slow-down adds 100 or so calories...significant, but not a deal-breaker by any means).

Interesting to note that exercise seems to ameliorate the effect in any case...

Cheers

[xAlphax]

PLoS Hub for Clinical Trials
http://www.plosone.org/article/info%...l.pone.0004377

Metabolic and Behavioral Compensations in Response to Caloric Restriction: Implications for the Maintenance of Weight Loss
Leanne M. Redman, Leonie K. Heilbronn¤a, Corby K. Martin, Lilian de Jonge, Donald A. Williamson, James P. Delany¤b, Eric Ravussin*, for the Pennington CALERIE team
Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America

Background
Metabolic and behavioral adaptations to caloric restriction (CR) in free-living conditions have not yet been objectively measured.

Methodology and Principal Findings
Forty-eight (36.8±1.0 y), overweight (BMI 27.8±0.7 kg/m2) participants were randomized to four groups for 6-months; Control: energy intake at 100% of energy requirements; CR: 25% calorie restriction; CR+EX: 12.5% CR plus 12.5% increase in energy expenditure by structured exercise; LCD: low calorie diet (890 kcal/d) until 15% weight reduction followed by weight maintenance. Body composition (DXA) and total daily energy expenditure (TDEE) over 14-days by doubly labeled water (DLW) and activity related energy activity (AREE) were measured after 3 (M3) and 6 (M6) months of intervention. Weight changes at M6 were −1.0±1.1% (Control), −10.4±0.9% (CR), −10.0±0.8% (CR+EX) and −13.9±0.8% (LCD). At M3, absolute TDEE was significantly reduced in CR (−454±76 kcal/d) and LCD (−633±66 kcal/d) but not in CR+EX or controls. At M6 the reduction in TDEE remained lower than baseline in CR (−316±118 kcal/d) and LCD (−389±124 kcal/d) but reached significance only when CR and LCD were combined (−351±83 kcal/d). In response to caloric restriction (CR/LCD combined), TDEE adjusted for body composition, was significantly lower by −431±51 and −240±83 kcal/d at M3 and M6, respectively, indicating a metabolic adaptation. Likewise, physical activity (TDEE adjusted for sleeping metabolic rate) was significantly reduced from baseline at both time points. For control and CR+EX, adjusted TDEE (body composition or sleeping metabolic rate) was not changed at either M3 or M6.

Conclusions
For the first time we show that in free-living conditions, CR results in a metabolic adaptation and a behavioral adaptation with decreased physical activity levels. These data also suggest potential mechanisms by which CR causes large inter-individual variability in the rates of weight loss and how exercise may influence weight loss and weight loss maintenance.

Trial Registration
ClinicalTrials.gov NCT00099151

Thnx for posting this up babe :].

[TheLadiesMan]

Interesting article about metabolism and women. I quoted the study after the article.

A Faster Metabolism Could Lead to a Shorter Life


Women with slower metabolisms who struggle to keep their weight in check live longer than naturally skinny women, a new study reveals.

In life there is often a trade-off and it seems to be no different when it comes to one’s metabolism.

Strong links between lifespan and metabolic rate has been found in experiments on animals where creatures that have higher metabolic rates tend to have shorter lives than those that convert food into energy slower.

Previously there was no convincing evidence of the same being true for humans.

It has now been revealed that an increased metabolic rate in humans can actually speed up the aging process by the study of 652 volunteers.

American scientists from the National Institute of Health compared the metabolic rate and lifespan of healthy Pima Indians in Arizona over a 21-year period.

They measured how quickly the Indian’s bodies converted food into energy over a 24-hour period as well as their resting metabolic rate.

Those Indians with a higher metabolic rate tended to die earlier.

Researcher Dr Reiner Jumpertz believes that “this increased metabolic rate may lead to earlier organ damage.”

He was careful to point out that these findings do not apply to energy burnt up by exercise as “this activity clearly has beneficial effects on health.”

People with a slow metabolism who become fat are also unlikely to benefit because obesity puts people at risk of dying from heart disease, stroke and cancer.

Higher Energy Expenditure in Humans Predicts Natural Mortality

Reiner Jumpertz, Robert L. Hanson, Maurice L. Sievers, Peter H. Bennett, Robert G. Nelson and Jonathan Krakoff
Obesity and Diabetes Clinical Research Section (R.J., J.K.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona 85016; and Diabetes Epidemiology and Clinical Research Section (R.L.H., M.L.S., P.H.B., R.G.N.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona 85014

Address all correspondence and requests for reprints to: Reiner Jumpertz, MD, National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases, Department of Health and Human Services, 4212 North 16th Street, Phoenix, Arizona 85016. E-mail: jumpertzr@mail.nih.gov.

Context: Higher metabolic rates increase free radical formation, which may accelerate aging and lead to early mortality.

Objective: Our objective was to determine whether higher metabolic rates measured by two different methods predict early natural mortality in humans.

Design: Nondiabetic healthy Pima Indian volunteers (n = 652) were admitted to an inpatient unit for approximately 7 d as part of a longitudinal study of obesity and diabetes risk factors. Vital status of study participants was determined through December 31, 2006. Twenty-four-hour energy expenditure (24EE) was measured in 508 individuals, resting metabolic rate (RMR) was measured in 384 individuals, and 240 underwent both measurements on separate days. Data for 24EE were collected in a respiratory chamber between 1985 and 2006 with a mean (SD) follow-up time of 11.1 (6.5) yr and for RMR using an open-circuit respiratory hood system between 1982 and 2006 with a mean follow-up time of 15.4 (6.3) yr. Cox regression models were used to test the effect of EE on natural mortality, controlled for age, sex, and body weight.

Results: In both groups, 27 natural deaths occurred during the study period. For each 100-kcal/24 h increase in EE, the risk of natural mortality increased by 1.29 (95% confidence interval = 1.00–1.66; P < 0.05) in the 24EE group and by 1.25 (95% confidence interval = 1.01–1.55; P < 0.05) in the RMR group, after adjustment for age, sex, and body weight in proportional hazard analyses.

Conclusions: Higher metabolic rates as reflected by 24EE or RMR predict early natural mortality, indicating that higher energy turnover may accelerate aging in humans.

[kentuckync]

great thread again, emma

[CR56BB]

Thanks for the info

[sa7soon]

Despite years of research, the treatment of obesity continues to revolve around the seemingly simple concept of balancing calorie expenditure with calorie intake. However, the determinants of energy expenditure, specifically resting metabolic rate, are an active area of research with many debatable issues. This review will address the calorie expenditure side of the scale, with the examination of the effect of dieting and exercise on resting metabolic rate.

LMAO, that actually made me burst out laughing!

Thank you so much for all the posts Emma, I've been reading like crazy for almost a week now!

[HighFivan]

I know this is a few years dated, but thanks for posting Emma!

Has anyone come across any interesting new finds? I've been enjoying the video blogs by Dr Layne Norton on Metabolic Damage

[shaneee]

Some reads/studies criticizing & disproving the fallacies of metabolic damage, set point theories in humans, and "yo-yo" dieting easing increases in adiposity later

http://www.beyonddiets.com/storage/R...et%20Point.pdf

http://www.ncbi.nlm.nih.gov/pubmed/7883999

http://journals.cambridge.org/downlo...8169c5ae3c5095

http://www.ncbi.nlm.nih.gov/pubmed/11063433

http://ajcn.nutrition.org/content/49/3/409.short

[OPcanDELIVER]

Might be a tad old but still a great read