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Ludwig DS. Carbohydrate-insulin model: does the conventional view of obesity reverse cause and effect? Philos Trans R Soc Lond B Biol Sci 2023; 378:20220211. [PMID: 37661740 PMCID: PMC10475871 DOI: 10.1098/rstb.2022.0211] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Accepted: 07/18/2023] [Indexed: 09/05/2023] Open
Abstract
Conventional obesity treatment, based on the First Law of Thermodynamics, assumes that excess body fat gain is driven by overeating, and that all calories are metabolically alike in this regard. Hence, to lose weight one must ultimately eat less and move more. However, this prescription rarely succeeds over the long term, in part because calorie restriction elicits predictable biological responses that oppose ongoing weight loss. The carbohydrate-insulin model posits the opposite causal direction: overeating doesn't drive body fat increase; instead, the process of storing excess fat drives overeating. A diet high in rapidly digestible carbohydrates raises the insulin-to-glucagon ratio, shifting energy partitioning towards storage in adipose, leaving fewer calories for metabolically active and fuel sensing tissues. Consequently, hunger increases, and metabolic rate slows in the body's attempt to conserve energy. A small shift in substrate partitioning though this mechanism could account for the slow but progressive weight gain characteristic of common forms of obesity. From this perspective, the conventional calorie-restricted, low-fat diet amounts to symptomatic treatment, failing to target the underlying predisposition towards excess fat deposition. A dietary strategy to lower insulin secretion may increase the effectiveness of long-term weight management and chronic disease prevention. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.
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Affiliation(s)
- David S. Ludwig
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, MA 02115, USA
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2
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Semmler G, Datz C, Trauner M. Eating, diet, and nutrition for the treatment of non-alcoholic fatty liver disease. Clin Mol Hepatol 2023; 29:S244-S260. [PMID: 36517001 PMCID: PMC10029946 DOI: 10.3350/cmh.2022.0364] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
Nutrition and dietary interventions are a central component in the pathophysiology, but also a cornerstone in the management of patients with non-alcoholic fatty liver disease (NAFLD). Summarizing our rapidly advancing understanding of how our diet influences our metabolism and focusing on specific effects on the liver, we provide a comprehensive overview of dietary concepts to counteract the increasing burden of NAFLD. Specifically, we emphasize the importance of dietary calorie restriction independently of the macronutrient composition together with adherence to a Mediterranean diet low in added fructose and processed meat that seems to exert favorable effects beyond calorie restriction. Also, we discuss intermittent fasting as a type of diet specifically tailored to decrease liver fat content and increase ketogenesis, awaiting future study results in NAFLD. Finally, personalized dietary recommendations could be powerful tools to increase the effectiveness of dietary interventions in patients with NAFLD considering the genetic background and the microbiome, among others.
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Affiliation(s)
- Georg Semmler
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Christian Datz
- Department of Internal Medicine, General Hospital Oberndorf, Teaching Hospital of the Paracelsus Medical University Salzburg, Oberndorf, Austria
| | - Michael Trauner
- Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
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Macronutrient Proportions and Fat Type Impact Ketogenicity and Shape the Circulating Lipidome in Dogs. Metabolites 2022; 12:metabo12070591. [PMID: 35888715 PMCID: PMC9324443 DOI: 10.3390/metabo12070591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/14/2022] [Accepted: 06/22/2022] [Indexed: 11/29/2022] Open
Abstract
Many physiological processes including ketogenesis are similar in dogs and humans, but there is little information available on the effect of carbohydrate restriction in dogs. Here, the ketogenicity and serum metabolic profiles of dogs were assessed after they had consumed high carbohydrate (HiCHO); high protein, low carbohydrate (PROT_LoCHO); or high fat, low carbohydrate (FAT_LoCHO) foods. Thirty-six dogs were fed HiCHO for 4 weeks, then randomized to PROT_LoCHO or FAT_LoCHO for 5 weeks. Dogs then crossed over to the other food for an additional 5 weeks. Generally, reduction of dietary carbohydrate by replacement with either protein or fat increased the energy required to maintain body weight, and fat had a greater effect. Postabsorptive energy availability derived mainly from glucose and triglycerides with HiCHO, from gluconeogenic amino acids and fatty acids with PROT_LoCHO, and from fatty acids and β-hydroxybutyrate with FAT_LoCHO. This study demonstrated that the reduction of carbohydrate in canine foods is potentially beneficial to dogs based on improvements in metabolism and supports the use of low-carbohydrate foods as safe and effective for healthy adult dogs.
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Ludwig DS, Aronne LJ, Astrup A, de Cabo R, Cantley LC, Friedman MI, Heymsfield SB, Johnson JD, King JC, Krauss RM, Lieberman DE, Taubes G, Volek JS, Westman EC, Willett WC, Yancy WS, Ebbeling CB. Reply to A Drewnowski et al, O Devinsky, D A Booth and E L Gibson, and D J Millward. Am J Clin Nutr 2022; 115:595-597. [PMID: 35139162 PMCID: PMC8990105 DOI: 10.1093/ajcn/nqab385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Louis J Aronne
- Comprehensive Weight Control Center, Weill Cornell Medicine, New York, NY, USA
| | - Arne Astrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Lewis C Cantley
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Mark I Friedman
- Monell Chemical Senses Center, Philadelphia, PA, USA,Nutrition Science Initiative, San Diego, CA, USA
| | - Steven B Heymsfield
- Metabolism & Body Composition Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - James D Johnson
- Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, Canada,Institute for Personalized Therapeutic Nutrition, Vancouver, Canada
| | - Janet C King
- Department of Nutritional Sciences & Toxicology, University of California Berkeley, Berkeley, CA, USA
| | - Ronald M Krauss
- Departments of Pediatrics and Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Daniel E Lieberman
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Gary Taubes
- Nutrition Science Initiative, San Diego, CA, USA
| | - Jeff S Volek
- Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - Eric C Westman
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Walter C Willett
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - William S Yancy
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Cara B Ebbeling
- From the New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, MA, USA,Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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Ludwig DS, Aronne LJ, Astrup A, de Cabo R, Cantley LC, Friedman MI, Heymsfield SB, Johnson JD, King JC, Krauss RM, Lieberman DE, Taubes G, Volek JS, Westman EC, Willett WC, Yancy WS, Ebbeling CB. The carbohydrate-insulin model: a physiological perspective on the obesity pandemic. Am J Clin Nutr 2021; 114:1873-1885. [PMID: 34515299 PMCID: PMC8634575 DOI: 10.1093/ajcn/nqab270] [Citation(s) in RCA: 122] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 07/26/2021] [Indexed: 12/29/2022] Open
Abstract
According to a commonly held view, the obesity pandemic is caused by overconsumption of modern, highly palatable, energy-dense processed foods, exacerbated by a sedentary lifestyle. However, obesity rates remain at historic highs, despite a persistent focus on eating less and moving more, as guided by the energy balance model (EBM). This public health failure may arise from a fundamental limitation of the EBM itself. Conceptualizing obesity as a disorder of energy balance restates a principle of physics without considering the biological mechanisms that promote weight gain. An alternative paradigm, the carbohydrate-insulin model (CIM), proposes a reversal of causal direction. According to the CIM, increasing fat deposition in the body-resulting from the hormonal responses to a high-glycemic-load diet-drives positive energy balance. The CIM provides a conceptual framework with testable hypotheses for how various modifiable factors influence energy balance and fat storage. Rigorous research is needed to compare the validity of these 2 models, which have substantially different implications for obesity management, and to generate new models that best encompass the evidence.
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Affiliation(s)
- David S Ludwig
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Louis J Aronne
- Comprehensive Weight Control Center, Weill Cornell Medicine, New York, NY, USA
| | - Arne Astrup
- Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Lewis C Cantley
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Mark I Friedman
- Monell Chemical Senses Center, Philadelphia, PA, USA
- Nutrition Science Initiative, San Diego, CA, USA
| | - Steven B Heymsfield
- Metabolism & Body Composition Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - James D Johnson
- Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
- Institute for Personalized Therapeutic Nutrition, Vancouver, British Columbia, Canada
| | - Janet C King
- Department of Nutritional Sciences & Toxicology, University of California Berkeley, Berkeley, CA, USA
| | - Ronald M Krauss
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Daniel E Lieberman
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Gary Taubes
- Nutrition Science Initiative, San Diego, CA, USA
| | - Jeff S Volek
- Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - Eric C Westman
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Walter C Willett
- Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA, USA
- Channing Division of Network Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - William S Yancy
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Cara B Ebbeling
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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Landry MJ, Crimarco A, Gardner CD. Benefits of Low Carbohydrate Diets: a Settled Question or Still Controversial? Curr Obes Rep 2021; 10:409-422. [PMID: 34297345 PMCID: PMC9621749 DOI: 10.1007/s13679-021-00451-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/31/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW The purpose of this review was to provide an update on the available data on the benefits of low-carbohydrate (low-carb) diets for weight management and type 2 diabetes (T2DM) and determine if low-carb diets were a settled question or still controversial. RECENT FINDINGS Most of the recent published literature in this area consists of reviews of past trials, with a relatively smaller number of recent trials. Low-carb is most commonly compared to low-fat, with problematically inconsistent definitions of both. There are numerous challenges in trying to draw clear conclusions about efficacy and effectiveness. Short-term vs. long-term effects can differ, which is likely impacted by adherence. Adherence is very different between metabolic chamber or feeding studies vs. free-living. Body weight alone is a crude measure that fails to capture potentially important differences in lean-mass, fat-mass, and body water. Benefits for glycemic control need to be balanced with impacts on non-glycemic outcomes such as LDL-cholesterol, the microbiome, and inflammation. It is important to differentiate between low-carb and very-low carbohydrate diets (VLCD). To date no large-scale long-term clinical trials have been conducted testing whether low-carb diets can prevent T2DM. Many issues regarding benefits and risks of low-carb diets remain controversial or unresolved, particularly for VLCD. Some of the recent, better studies highlighted in this review suggest strategies for resolving these controversies.
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Affiliation(s)
- Matthew J Landry
- Stanford Prevention Research Center, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Anthony Crimarco
- Stanford Prevention Research Center, School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Christopher D Gardner
- Stanford Prevention Research Center, School of Medicine, Stanford University, Palo Alto, CA, USA.
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Ludwig DS, Ebbeling CB. Letter to the Editor: Reply to Guyenet and Hall. J Nutr 2021; 151:2497-2498. [PMID: 34363483 DOI: 10.1093/jn/nxab215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- David S Ludwig
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Cara B Ebbeling
- New Balance Foundation Obesity Prevention Center, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
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Abstract
PURPOSE OF REVIEW Precision nutrition and personalized diets are gaining popularity in nutritional science and medicine. To fully appreciate their potential benefits, a deep understanding of both macronutrients and nutrient-microbe interactions is required. RECENT FINDINGS Microbiome science has reaffirmed the importance of dietary fiber in microbial and host health. Additional macronutrients, digestible carbohydrate, protein and fat also influence the composition and diversity of the microbiome and, therefore, microbial response to dietary intervention. Attention to macronutrient source, dose, microbial effect and metabolite production allows the development of more established links between diet and health. SUMMARY The degree to which human diets need to be personalized for optimal health is still uncertain but a one-size-fits-all diet seems unlikely. However, for personal or precision nutrition to fulfill its promise, greater attention to the details of nutrient-microbe interactions will be required.
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Affiliation(s)
- John O'Grady
- APC Microbiome Ireland and Department of Medicine, University College Cork, National University of Ireland, Cork, Ireland
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Dent R, McPherson R, Harper ME. Factors affecting weight loss variability in obesity. Metabolism 2020; 113:154388. [PMID: 33035570 DOI: 10.1016/j.metabol.2020.154388] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/19/2020] [Accepted: 09/23/2020] [Indexed: 12/25/2022]
Abstract
Current obesity treatment strategies include diet, exercise, bariatric surgery, and a limited but growing repertoire of medications. Individual weight loss in response to each of these strategies is highly variable. Here we review research into factors potentially contributing to inter-individual variability in response to treatments for obesity, with a focus on studies in humans. Well-recognized factors associated with weight loss capacity include diet adherence, physical activity, sex, age, and specific medications. However, following control for each of these, differences in weight loss appear to persist in response to behavioral, pharmacological and surgical interventions. Adaptation to energy deficit involves complex feedback mechanisms, and inter-individual differences likely to arise from a host of poorly defined genetic factors, as well as differential responses in neurohormonal mechanisms (including gastrointestinal peptides), metabolic efficiency and capacity of tissues, non-exercise activity thermogenesis, thermogenic response to food, and in gut microbiome. A better understanding of the factors involved in inter-individual variability in response to therapies will guide more personalized approaches to the treatment of obesity.
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Affiliation(s)
- Robert Dent
- Department of Medicine, Division of Endocrinology and The Ottawa Hospital, University of Ottawa, 210 Melrose Ave, Ottawa, ON K1Y 4K7, Canada
| | - Ruth McPherson
- Atherogenomics Laboratory, Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON K1Y 4W7, Canada
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, Ottawa Institute of Systems Biology, University of Ottawa, 451 Smyth Rd., Ottawa, ON K1H 8M5, Canada.
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Ludwig DS. Reply to S Joshi. J Nutr 2020; 150:2836-2837. [PMID: 33044523 DOI: 10.1093/jn/nxaa214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- David S Ludwig
- From the New Balance Foundation Obesity Prevention Center, Boston Children's Hospital and Harvard Medical School, Boston, MA
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