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Tien DS, Hockey M, So D, Stanford J, Clarke ED, Collins CE, Staudacher HM. Recommendations for Designing, Conducting, and Reporting Feeding Trials in Nutrition Research. Adv Nutr 2024:100283. [PMID: 39134209 DOI: 10.1016/j.advnut.2024.100283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 07/05/2024] [Accepted: 08/07/2024] [Indexed: 09/01/2024] Open
Abstract
Double-blind, placebo-controlled, randomized controlled trials are the gold standard for clinical trials in nutrition science. For trials of whole diets, dietary counseling is advantageous as they offer clinical translatability although can vary in the fidelity of the intended intervention from participant to participant and across studies. Feeding trials, in which most or all food is provided, offer high precision and can provide proof-of-concept evidence that a dietary intervention is efficacious and can also better evaluate the effect of known quantities of foods and nutrients on physiology. However, they come with additional methodological complexities. Feeding trials also call for a variety of unique methodological considerations, not least of which relate to the design and delivery of diets to participants. This review aims to provide a comprehensive summary of recommendations for design and conduct of feeding trials, encompassing domiciled and nondomiciled feeding trials. Several pertinent aspects of trial design and methodology are discussed, including defining the study population to maximize retention, safety, and generalizability of findings, recommendations for design of control interventions and optimizing blinding, and specific considerations for clinical populations. A detailed stepwise process for menu design, development, validation, and delivery are also presented. These recommendations aim to facilitate methodologic consistency and execution of high-quality feeding trials, ultimately facilitating improved understanding of the role of diet in treating disease and the underpinning mechanisms.
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Affiliation(s)
- Delyse Sy Tien
- Food & Mood Centre, the Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Victoria, Australia
| | - Meghan Hockey
- Food & Mood Centre, the Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Victoria, Australia
| | - Daniel So
- Department of Gastroenterology, Monash University and Alfred Health, Melbourne, Victoria, Australia
| | - Jordan Stanford
- School of Health Sciences, College of Health Medicine and Wellbeing, the University of Newcastle, New South Wales, Australia; Food and Nutrition Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Erin D Clarke
- School of Health Sciences, College of Health Medicine and Wellbeing, the University of Newcastle, New South Wales, Australia; Food and Nutrition Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Clare E Collins
- School of Health Sciences, College of Health Medicine and Wellbeing, the University of Newcastle, New South Wales, Australia; Food and Nutrition Research Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Heidi M Staudacher
- Food & Mood Centre, the Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Victoria, Australia.
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Wong JMW, Ludwig DS, Allison DB, Baidwan N, Bielak L, Chiu CY, Dickinson SL, Golzarri-Arroyo L, Heymsfield SB, Holmes L, Jansen LT, Lesperance D, Mehta T, Sandman M, Steltz SK, Wong WW, Yu S, Ebbeling CB. Design and conduct of a randomized controlled feeding trial in a residential setting with mitigation for COVID-19. Contemp Clin Trials 2024; 140:107490. [PMID: 38458559 DOI: 10.1016/j.cct.2024.107490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/26/2024] [Accepted: 03/05/2024] [Indexed: 03/10/2024]
Abstract
BACKGROUND Evaluating effects of different macronutrient diets in randomized trials requires well defined infrastructure and rigorous methods to ensure intervention fidelity and adherence. METHODS This controlled feeding study comprised two phases. During a Run-in phase (14-15 weeks), study participants (18-50 years, BMI, ≥27 kg/m2) consumed a very-low-carbohydrate (VLC) diet, with home delivery of prepared meals, at an energy level to promote 15 ± 3% weight loss. During a Residential phase (13 weeks), participants resided at a conference center. They received a eucaloric VLC diet for three weeks and then were randomized to isocaloric test diets for 10 weeks: VLC (5% energy from carbohydrate, 77% from fat), high-carbohydrate (HC)-Starch (57%, 25%; including 20% energy from refined grains), or HC-Sugar (57%, 25%; including 20% sugar). Outcomes included measures of body composition and energy expenditure, chronic disease risk factors, and variables pertaining to physiological mechanisms. Six cores provided infrastructure for implementing standardized protocols: Recruitment, Diet and Meal Production, Participant Support, Assessments, Regulatory Affairs and Data Management, and Statistics. The first participants were enrolled in May 2018. Participants residing at the conference center at the start of the COVID-19 pandemic completed the study, with each core implementing mitigation plans. RESULTS Before early shutdown, 77 participants were randomized, and 70 completed the trial (65% of planned completion). Process measures indicated integrity to protocols for weighing menu items, within narrow tolerance limits, and participant adherence, assessed by direct observation and continuous glucose monitoring. CONCLUSION Available data will inform future research, albeit with less statistical power than originally planned.
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Affiliation(s)
- Julia M W Wong
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - David S Ludwig
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - David B Allison
- Indiana University School of Public Health, Bloomington, IN, United States of America
| | - Navneet Baidwan
- Department of Health Services Administration, School of Health Professions, University of Alabama at Birmingham, United States of America
| | - Lisa Bielak
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America
| | - Chia-Ying Chiu
- Division of Pulmonary, Allergy, and Acute Critical Care, Department of Medicine, University of Alabama at Birmingham, United States of America
| | - Stephanie L Dickinson
- Indiana University School of Public Health, Bloomington, IN, United States of America
| | | | - Steven B Heymsfield
- Metabolism & Body Composition Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, United States of America
| | - Lauren Holmes
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America
| | - Lisa T Jansen
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America; Harvard Medical School, Boston, MA, United States of America
| | - Donna Lesperance
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America
| | - Tapan Mehta
- Department of Health Services Administration, School of Health Professions, University of Alabama at Birmingham, United States of America
| | - Megan Sandman
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America
| | - Sarah K Steltz
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America
| | - William W Wong
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States of America
| | - Shui Yu
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America
| | - Cara B Ebbeling
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, United States of America; Harvard Medical School, Boston, MA, United States of America.
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Are methods of estimating fat-free mass loss with energy-restricted diets accurate? Eur J Clin Nutr 2022; 77:525-531. [PMID: 36076068 DOI: 10.1038/s41430-022-01203-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/08/2022]
Abstract
BACKGROUND/OBJECTIVES Fat-free mass (FFM) often serves as a body composition outcome variable in weight loss studies. An important assumption is that the proportions of components that make up FFM remain stable following weight loss; some body composition models rely on these "constants". This exploratory study examined key FFM component proportions before and following weight loss in two studies of participants with overweight and obesity. SUBJECTS/METHODS 201 men and women consumed calorie-restricted moderate- or very-low carbohydrate diets leading to 10-18% weight loss in 9-15 weeks. Measured total body fat, lean mass, bone mineral, total body water (TBW), and body weight at baseline and follow-up were used to derive FFM and its chemical proportions using a four-component model. RESULTS A consistent finding in both studies was a non-significant reduction in bone mineral and a corresponding increase (p < 0.001) in bone mineral/FFM; FFM density increased significantly in one group of women and in all four participant groups combined (both, p < 0.05). FFM hydration (TBW/FFM) increased in all groups of men and women, one significantly (p < 0.01), and in the combined sample (borderline, p < 0.10). The proportion of FFM as protein decreased across all groups, two significantly (p < 0.05-0.01) and in the combined sample (p < 0.05). CONCLUSION FFM relative proportions of chemical components may not be identical before and after short-term weight loss, an observation impacting some widely used body composition models and methods. Caution is thus needed when applying FFM as a safety signal or to index metabolic evaluations in clinical trials when these body composition approaches are used.
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Ludwig DS, Norwitz NG, Feldman D, Soto-Mota A, Kalayjian T. Reply to M Mindrum and J Moore et al. Curr Dev Nutr 2022; 6:nzac029. [PMID: 35670750 PMCID: PMC9154284 DOI: 10.1093/cdn/nzac029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
| | | | | | - Adrian Soto-Mota
- Metabolic Diseases Research Unit, National Institute for Medical Sciences
and Nutrition Salvador Zubiran, Tlalpan, Mexico
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Wong JMW, Yu S, Ma C, Mehta T, Dickinson SL, Allison DB, Heymsfield SB, Ebbeling CB, Ludwig DS. Stimulated Insulin Secretion Predicts Changes in Body Composition Following Weight Loss in Adults with High BMI. J Nutr 2022; 152:655-662. [PMID: 34587231 DOI: 10.1093/jn/nxab315] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/02/2021] [Accepted: 08/26/2021] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND The aim of obesity treatment is to promote loss of fat relative to lean mass. However, body composition changes with calorie restriction differ among individuals. OBJECTIVES The goal of this study was to test the hypothesis that insulin secretion predicts body composition changes among young and middle-age adults with high BMI (in kg/m2) following major weight loss. METHODS Exploratory analyses were conducted with pre-randomization data from 2 large feeding trials: the Framingham, Boston, Bloomington, Birmingham, and Baylor study (FB4; n = 82, 43.9% women, BMI ≥27) and the Framingham State Food Study [(FS)2; n = 161, 69.6% women, BMI ≥25]. Participants in the 2 trials consumed calorie-restricted moderate-carbohydrate or very-low-carbohydrate diets to produce 12-18% weight loss in ∼14 wk or 10-14% in ∼10 wk, respectively. We determined insulin concentration 30 min after a 75-g oral glucose load (insulin-30) as a measure of insulin secretion and HOMA-IR as a measure of insulin resistance at baseline. Body composition was determined by DXA at baseline and post-weight loss. Associations were analyzed using general linear models with adjustment for covariates. RESULTS In FB4, higher insulin-30 was associated with a smaller decrease in fat mass (0.441 kg per 100 μIU/mL increment in baseline insulin-30; P = 0.005; -1.20-kg mean difference between the first compared with the fifth group of insulin-30) and a larger decrease in lean mass (-0.465 kg per 100 μIU/mL; P = 0.004; 1.27-kg difference). Participants with higher insulin-30 lost a smaller proportion of weight loss as fat (-3.37% per 100 μIU/mL; P = 0.003; 9.20% difference). Greater HOMA-IR was also significantly associated with adverse body composition changes. Results from (FS)2 were qualitatively similar but of a smaller magnitude. CONCLUSIONS Baseline insulin dynamics predict substantial individual differences in body composition following weight loss. These findings may inform understanding of the pathophysiological basis for weight regain and the design of more effective obesity treatment. Registered at clinicaltrials.gov as NCT03394664 and NCT02068885.
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Affiliation(s)
- Julia M W Wong
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Shui Yu
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, MA, USA
| | - Clement Ma
- Harvard Medical School, Boston, MA, USA.,Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston, MA, USA
| | - Tapan Mehta
- Department of Health Services Administration, School of Health Professions, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - David B Allison
- Indiana University School of Public Health-Bloomington, Bloomington, IN, USA
| | - Steven B Heymsfield
- Metabolism & Body Composition Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Cara B Ebbeling
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - David S Ludwig
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
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Ebbeling CB, Knapp A, Johnson A, Wong JMW, Greco KF, Ma C, Mora S, Ludwig DS. Effects of a low-carbohydrate diet on insulin-resistant dyslipoproteinemia-a randomized controlled feeding trial. Am J Clin Nutr 2021; 115:154-162. [PMID: 34582545 PMCID: PMC8755039 DOI: 10.1093/ajcn/nqab287] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/10/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Carbohydrate restriction shows promise for diabetes, but concerns regarding high saturated fat content of low-carbohydrate diets limit widespread adoption. OBJECTIVES This preplanned ancillary study aimed to determine how diets varying widely in carbohydrate and saturated fat affect cardiovascular disease (CVD) risk factors during weight-loss maintenance. METHODS After 10-14% weight loss on a run-in diet, 164 participants (70% female; BMI = 32.4 ± 4.8 kg/m2) were randomly assigned to 3 weight-loss maintenance diets for 20 wk. The prepared diets contained 20% protein and differed 3-fold in carbohydrate (Carb) and saturated fat as a proportion of energy (Low-Carb: 20% carbohydrate, 21% saturated fat; Moderate-Carb: 40%, 14%; High-Carb: 60%, 7%). Fasting plasma samples were collected prerandomization and at 20 wk. Lipoprotein insulin resistance (LPIR) score was calculated from triglyceride-rich, high-density, and low-density lipoprotein particle (TRL-P, HDL-P, LDL-P) sizes and subfraction concentrations (large/very large TRL-P, large HDL-P, small LDL-P). Other outcomes included lipoprotein(a), triglycerides, HDL cholesterol, LDL cholesterol, adiponectin, and inflammatory markers. Repeated measures ANOVA was used for intention-to-treat analysis. RESULTS Retention was 90%. Mean change in LPIR (scale 0-100) differed by diet in a dose-dependent fashion: Low-Carb (-5.3; 95% CI: -9.2, -1.5), Moderate-Carb (-0.02; 95% CI: -4.1, 4.1), High-Carb (3.6; 95% CI: -0.6, 7.7), P = 0.009. Low-Carb also favorably affected lipoprotein(a) [-14.7% (95% CI: -19.5, -9.5), -2.1 (95% CI: -8.2, 4.3), and 0.2 (95% CI: -6.0, 6.8), respectively; P = 0.0005], triglycerides, HDL cholesterol, large/very large TRL-P, large HDL-P, and adiponectin. LDL cholesterol, LDL-P, and inflammatory markers did not differ by diet. CONCLUSIONS A low-carbohydrate diet, high in saturated fat, improved insulin-resistant dyslipoproteinemia and lipoprotein(a), without adverse effect on LDL cholesterol. Carbohydrate restriction might lower CVD risk independently of body weight, a possibility that warrants study in major multicentered trials powered on hard outcomes. The registry is available through ClinicialTrials.gov: https://clinicaltrials.gov/ct2/show/NCT02068885.
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Affiliation(s)
- Cara B Ebbeling
- New Balance Foundation Obesity Prevention Center, Boston Children's
Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA,
USA
| | - Amy Knapp
- Department of Biology, Framingham State University,
Framingham, MA, USA
| | - Ann Johnson
- Department of Food and Nutrition, Framingham State
University, Framingham, MA, USA
| | - Julia M W Wong
- New Balance Foundation Obesity Prevention Center, Boston Children's
Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA,
USA
| | - Kimberly F Greco
- Institutional Centers for Clinical and Translational Research, Boston
Children's Hospital, Boston, MA, USA
| | - Clement Ma
- Harvard Medical School, Boston, MA,
USA,Dana-Farber/Boston Children's Cancer and Blood Disorders
Center, Boston, MA, USA
| | - Samia Mora
- Harvard Medical School, Boston, MA,
USA,Center for Lipid Metabolomics, Divisions of Preventive and Cardiovascular
Medicine, Brigham and Women's Hospital, Boston,
MA, USA
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Ebbeling CB, Bielak L, Lakin PR, Klein GL, Wong JMW, Luoto PK, Wong WW, Ludwig DS. Energy Requirement Is Higher During Weight-Loss Maintenance in Adults Consuming a Low- Compared with High-Carbohydrate Diet. J Nutr 2020; 150:2009-2015. [PMID: 32470981 PMCID: PMC7398766 DOI: 10.1093/jn/nxaa150] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/18/2019] [Accepted: 05/04/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Longer-term feeding studies suggest that a low-carbohydrate diet increases energy expenditure, consistent with the carbohydrate-insulin model of obesity. However, the validity of methodology utilized in these studies, involving doubly labeled water (DLW), has been questioned. OBJECTIVE The aim of this study was to determine whether dietary energy requirement for weight-loss maintenance is higher on a low- compared with high-carbohydrate diet. METHODS The study reports secondary outcomes from a feeding study in which the primary outcome was total energy expenditure (TEE). After attaining a mean Run-in weight loss of 10.5%, 164 adults (BMI ≥25 kg/m2; 70.1% women) were randomly assigned to Low-Carbohydrate (percentage of total energy from carbohydrate, fat, protein: 20/60/20), Moderate-Carbohydrate (40/40/20), or High-Carbohydrate (60/20/20) Test diets for 20 wk. Calorie content was adjusted to maintain individual body weight within ± 2 kg of the postweight-loss value. In analyses by intention-to-treat (ITT, completers, n = 148) and per protocol (PP, completers also achieving weight-loss maintenance, n = 110), we compared the estimated energy requirement (EER) from 10 to 20 wk of the Test diets using ANCOVA. RESULTS Mean EER was higher in the Low- versus High-Carbohydrate group in models of varying covariate structure involving ITT [ranging from 181 (95% CI: 8-353) to 246 (64-427) kcal/d; P ≤0.04] and PP [ranging from 245 (43-446) to 323 (122-525) kcal/d; P ≤0.02]. This difference remained significant in sensitivity analyses accounting for change in adiposity and possible nonadherence. CONCLUSIONS Energy requirement was higher on a low- versus high-carbohydrate diet during weight-loss maintenance in adults, commensurate with TEE. These data are consistent with the carbohydrate-insulin model and lend qualified support for the validity of the DLW method with diets varying in macronutrient composition. This trial was registered at clinicaltrials.gov as NCT02068885.
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Affiliation(s)
- Cara B Ebbeling
- New Balance Foundation Obesity Prevention Center, Boston, MA, USA
| | - Lisa Bielak
- New Balance Foundation Obesity Prevention Center, Boston, MA, USA
| | - Paul R Lakin
- Institutional Centers for Clinical and Translational Research; Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Gloria L Klein
- New Balance Foundation Obesity Prevention Center, Boston, MA, USA
| | - Julia M W Wong
- New Balance Foundation Obesity Prevention Center, Boston, MA, USA
| | - Patricia K Luoto
- Department of Food and Nutrition, Framingham State University, Framingham, MA, USA
| | - William W Wong
- USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine,Houston, TX, USA
| | - David S Ludwig
- New Balance Foundation Obesity Prevention Center, Boston, MA, USA
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Ebbeling CB, Feldman HA, Klein GL, Wong JMW, Bielak L, Steltz SK, Luoto PK, Wolfe RR, Wong WW, Ludwig DS. Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial. BMJ 2018; 363:k4583. [PMID: 30429127 PMCID: PMC6233655 DOI: 10.1136/bmj.k4583] [Citation(s) in RCA: 156] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/24/2018] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To determine the effects of diets varying in carbohydrate to fat ratio on total energy expenditure. DESIGN Randomized trial. SETTING Multicenter collaboration at US two sites, August 2014 to May 2017. PARTICIPANTS 164 adults aged 18-65 years with a body mass index of 25 or more. INTERVENTIONS After 12% (within 2%) weight loss on a run-in diet, participants were randomly assigned to one of three test diets according to carbohydrate content (high, 60%, n=54; moderate, 40%, n=53; or low, 20%, n=57) for 20 weeks. Test diets were controlled for protein and were energy adjusted to maintain weight loss within 2 kg. To test for effect modification predicted by the carbohydrate-insulin model, the sample was divided into thirds of pre-weight loss insulin secretion (insulin concentration 30 minutes after oral glucose). MAIN OUTCOME MEASURES The primary outcome was total energy expenditure, measured with doubly labeled water, by intention-to-treat analysis. Per protocol analysis included participants who maintained target weight loss, potentially providing a more precise effect estimate. Secondary outcomes were resting energy expenditure, measures of physical activity, and levels of the metabolic hormones leptin and ghrelin. RESULTS Total energy expenditure differed by diet in the intention-to-treat analysis (n=162, P=0.002), with a linear trend of 52 kcal/d (95% confidence interval 23 to 82) for every 10% decrease in the contribution of carbohydrate to total energy intake (1 kcal=4.18 kJ=0.00418 MJ). Change in total energy expenditure was 91 kcal/d (95% confidence interval -29 to 210) greater in participants assigned to the moderate carbohydrate diet and 209 kcal/d (91 to 326) greater in those assigned to the low carbohydrate diet compared with the high carbohydrate diet. In the per protocol analysis (n=120, P<0.001), the respective differences were 131 kcal/d (-6 to 267) and 278 kcal/d (144 to 411). Among participants in the highest third of pre-weight loss insulin secretion, the difference between the low and high carbohydrate diet was 308 kcal/d in the intention-to-treat analysis and 478 kcal/d in the per protocol analysis (P<0.004). Ghrelin was significantly lower in participants assigned to the low carbohydrate diet compared with those assigned to the high carbohydrate diet (both analyses). Leptin was also significantly lower in participants assigned to the low carbohydrate diet (per protocol). CONCLUSIONS Consistent with the carbohydrate-insulin model, lowering dietary carbohydrate increased energy expenditure during weight loss maintenance. This metabolic effect may improve the success of obesity treatment, especially among those with high insulin secretion. TRIAL REGISTRATION ClinicalTrials.gov NCT02068885.
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Affiliation(s)
- Cara B Ebbeling
- New Balance Foundation Obesity Prevention Center, Division of Endocrinology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA, USA
| | - Henry A Feldman
- Harvard Medical School, Boston, MA, USA
- Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Boston, MA, USA
| | - Gloria L Klein
- New Balance Foundation Obesity Prevention Center, Division of Endocrinology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Julia M W Wong
- New Balance Foundation Obesity Prevention Center, Division of Endocrinology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA, USA
| | - Lisa Bielak
- New Balance Foundation Obesity Prevention Center, Division of Endocrinology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Sarah K Steltz
- New Balance Foundation Obesity Prevention Center, Division of Endocrinology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Patricia K Luoto
- Department of Food and Nutrition, Framingham State University, Framingham, MA, USA
| | - Robert R Wolfe
- University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - William W Wong
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - David S Ludwig
- New Balance Foundation Obesity Prevention Center, Division of Endocrinology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA, USA
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