Complex Effects of Dietary Manipulation on Metabolic Function, Inflammation and Health
NCT ID: NCT02706262
Last Updated: 2026-01-27
Study Results
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Basic Information
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ACTIVE_NOT_RECRUITING
NA
180 participants
INTERVENTIONAL
2016-02-29
2027-12-31
Brief Summary
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Detailed Description
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In people that do develop the typical "complications" associated with obesity weight loss has profound therapeutic effects. Currently, there are three distinctly different types of diets that have demonstrated considerable benefits in improving cardiometabolic health in both lean and obese people: 1) a Mediterranean diet, 2) a low-carbohydrate, ketogenic diet, and 3) a plant-based, very-low-fat diet. However, there is considerable inter-individual variability in body weight loss among people in response to any given diet, and it is not known why some people lose more weight with one diet than another. The mechanisms responsible for the different weight and metabolic responses to specific types of diets and the independent effects of weight loss and dietary macronutrient composition on cardiometabolic health are unclear.
The overarching goal of this project is therefore to fill these gaps in knowledge by conducting a careful cross-sectional characterization of metabolically normal lean, metabolically normal obese and metabolically abnormal obese individuals to compare body composition, body fat distribution, the plasma metabolome, systemic and adipose tissue inflammation and immune system function, adipose tissue and muscle biological function, the gut microbiome, the brain's structure, cognitive function and central reward mechanisms, and taste sensation between groups. . Metabolically abnormal obese participants will then be randomized to follow a Mediterranean, a low-carbohydrate ketogenic or a plant-based, very-low-fat diet to examine the different effects of these diets on the above outcomes with the purpose to determine the beneficial or potentially harmful effects of these different diets.
Conditions
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Study Design
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RANDOMIZED
PARALLEL
OTHER
NONE
Study Groups
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Metabolically normal lean - Baseline testing only
Metabolically normal lean - Lean individuals that have good glucose (sugar) control, normal plasma triglyceride (fat) levels and a low liver fat content.
Dietary intervention - None.
No interventions assigned to this group
Metabolically normal obese - Baseline testing only
Metabolically normal obese - Persons with obesity that have good glucose (sugar) control, normal plasma triglyceride (fat) levels and a low liver fat content.
Dietary intervention - None.
No interventions assigned to this group
Metabolically abnormal obese - Mediterranean diet
Metabolically abnormal obese - Persons with obesity with glucose levels higher than recommended and a moderate to high amount of fat in the liver.
Dietary intervention - A nutritionally balanced diet that includes fruits, vegetables, fish, beans, whole grains, and olive oil with approximately 50% of daily calories coming from complex carbohydrates, 30% of calories from fat, and 20% of calories from protein.
Metabolically abnormal obese - Mediterranean diet
The effect of consuming a Mediterranean diet will be examined over 3 different phases: (i) weight maintenance for 4 to 8 weeks, with all meals provided; (ii) controlled 7-10% weight loss with caloric intake reduced by 25% to achieve the desired amount of weight loss in about 4 to 5 months with all meals provided; and (iii) Independent weight loss for about 4 months. During the independent weight loss phase of the study subjects will be asked to continue to consume a Mediterranean diet but will prepare all their food at home. No food will be provided during this portion of the study.
Annual Follow-up Visits
Metabolic health will be assessed 1 and 2-years after competing the diet intervention study. No intervention will be performed during the time.
Metabolically abnormal obese - Low carbohydrate ketogenic diet
Metabolically abnormal obese - Persons with obesity with glucose levels higher than recommended and a moderate to high amount of fat in the liver.
Dietary intervention - A very-low-carbohydrate, adequate protein, high-fat diet containing 20 grams of carbohydrate or less per day (about 5% of calories), derived mainly from vegetables.
Metabolically abnormal obese - Low carbohydrate ketogenic diet
The effect of consuming a low-carbohydrate, ketogenic diet will be examined over 3 different phases: (i) weight maintenance for 4 to 8 weeks, with all meals provided; (ii) controlled 7-10% weight loss with caloric intake reduced by 25% to achieve the desired amount of weight loss in about 4 to 5 months with all meals provided; and (iii) Independent weight loss for about 4 months. During the independent weight loss phase of the study subjects will be asked to continue to consume a low carbohydrate ketogenic diet but will prepare all their food at home. No food will be provided during this portion of the study.
Annual Follow-up Visits
Metabolic health will be assessed 1 and 2-years after competing the diet intervention study. No intervention will be performed during the time.
Metabolically abnormal obese - Plant-based very-low-fat diet
Metabolically abnormal obese - Persons with obesity with glucose levels higher than recommended and a moderate to high amount of fat in the liver.
Dietary intervention - A plant-based diet high in complex carbohydrates and low in fat, protein, and sodium, with approximately 70% of daily calories from carbohydrates, 15% from fat, and 15% from protein.
Metabolically abnormal obese - Plant-based, very-low-fat diet
The effect of consuming a plant-based, very-low-fat diet will be examined over 3 different phases: (i) weight maintenance for 4 to 8 weeks, with all meals provided; (ii) controlled 7-10% weight loss with caloric intake reduced by 25% to achieve the desired amount of weight loss in about 4 to 5 months with all meals provided; and (iii) Independent weight loss for about 4 months. During the independent weight loss phase of the study subjects will be asked to continue to consume a plant-based, very-low-fat diet but will prepare all their food at home. No food will be provided during this portion of the study.
Annual Follow-up Visits
Metabolic health will be assessed 1 and 2-years after competing the diet intervention study. No intervention will be performed during the time.
Interventions
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Metabolically abnormal obese - Mediterranean diet
The effect of consuming a Mediterranean diet will be examined over 3 different phases: (i) weight maintenance for 4 to 8 weeks, with all meals provided; (ii) controlled 7-10% weight loss with caloric intake reduced by 25% to achieve the desired amount of weight loss in about 4 to 5 months with all meals provided; and (iii) Independent weight loss for about 4 months. During the independent weight loss phase of the study subjects will be asked to continue to consume a Mediterranean diet but will prepare all their food at home. No food will be provided during this portion of the study.
Metabolically abnormal obese - Low carbohydrate ketogenic diet
The effect of consuming a low-carbohydrate, ketogenic diet will be examined over 3 different phases: (i) weight maintenance for 4 to 8 weeks, with all meals provided; (ii) controlled 7-10% weight loss with caloric intake reduced by 25% to achieve the desired amount of weight loss in about 4 to 5 months with all meals provided; and (iii) Independent weight loss for about 4 months. During the independent weight loss phase of the study subjects will be asked to continue to consume a low carbohydrate ketogenic diet but will prepare all their food at home. No food will be provided during this portion of the study.
Metabolically abnormal obese - Plant-based, very-low-fat diet
The effect of consuming a plant-based, very-low-fat diet will be examined over 3 different phases: (i) weight maintenance for 4 to 8 weeks, with all meals provided; (ii) controlled 7-10% weight loss with caloric intake reduced by 25% to achieve the desired amount of weight loss in about 4 to 5 months with all meals provided; and (iii) Independent weight loss for about 4 months. During the independent weight loss phase of the study subjects will be asked to continue to consume a plant-based, very-low-fat diet but will prepare all their food at home. No food will be provided during this portion of the study.
Annual Follow-up Visits
Metabolic health will be assessed 1 and 2-years after competing the diet intervention study. No intervention will be performed during the time.
Eligibility Criteria
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Inclusion Criteria
* Metabolically normal lean and obese subjects must have intrahepatic triglyceride (IHTG) content ≤5%; plasma triglyceride (TG) concentration \<150 mg/dl; fasting plasma glucose concentration \<100 mg/dl, 2-hr oral glucose tolerance plasma glucose concentration \<140 mg/dl, and hemoglobin A1C ≤5.6%
* Metabolically abnormal obese subjects must have intrahepatic triglyceride (IHTG) content ≥5.6%; HbA1C ≥5.7%, or fasting plasma glucose concentration ≥100 mg/dl, or 2-hr oral glucose tolerance test (OGTT) plasma glucose concentration ≥140 mg/dl.
Exclusion Criteria
* Previous bariatric surgery where the gastrointestinal tract is reconstructed such as Roux-en-Y, sleeve gastrectomy and biliopancreatic diversion surgeries
* Laparoscopic adjustable gastric band (lab band) surgery within the last 3 years
* Structured exercise ≥250 min per week (e.g., brisk walking)
* Unstable weight (\>4% change during the last 2 months before entering the study)
* Significant organ system dysfunction (e.g., diabetes requiring medications, severe pulmonary, kidney or cardiovascular disease)
* Polycystic ovary syndrome
* Cancer or cancer that has been in remission for \<5 years
* Major psychiatric illness
* Conditions that render subject unable to complete all testing procedures (e.g., severe ambulatory impairments, limb amputations, or metal implants that interfere with imaging procedures; coagulation disorders)
* Use of medications that are known to affect the study outcome measures (e.g., steroids, non-statin lipid-lowering medications) or increase the risk of study procedures (e.g., anticoagulants) and that cannot be temporarily discontinued for this study
* Use of antibiotics in last 60 days
* Smoke cigarettes \> 10 cigarettes/week
* Use marijuana \>2 x/week, or use of illegal drugs
* Men who consume \>21 units (e.g. glass of wine or bottle of beer) of alcohol per week and women who consume \>14 units of alcohol per week
* Pregnant or lactating women
* Vegans, vegetarians, those with lactose intolerance and/or severe aversions/sensitivities to eggs, fish, nuts, wheat and soy, and/or any individuals with food allergies that induce an anaphylactic response
* Persons who are not able to grant voluntary informed consent
* Persons who are unable or unwilling to follow the study protocol or who, for any reason, the research team considers not an appropriate candidate for this study, including non-compliance with screening appointments or study visits
18 Years
55 Years
ALL
Yes
Sponsors
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Washington University School of Medicine
OTHER
Responsible Party
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Principal Investigators
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Samuel Klein, MD
Role: PRINCIPAL_INVESTIGATOR
Washington University School of Medicine
Locations
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Washington University School of Medicine
St Louis, Missouri, United States
Countries
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References
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Stern JH, Smith GI, Chen S, Unger RH, Klein S, Scherer PE. Obesity dysregulates fasting-induced changes in glucagon secretion. J Endocrinol. 2019 Nov;243(2):149-160. doi: 10.1530/JOE-19-0201.
Eisenstein SA, Black KJ, Samara A, Koller JM, Dunn JP, Hershey T, Klein S, Smith GI. Striatal Dopamine Responses to Feeding are Altered in People with Obesity. Obesity (Silver Spring). 2020 Apr;28(4):765-771. doi: 10.1002/oby.22753. Epub 2020 Feb 21.
Petersen MC, Smith GI, Palacios HH, Farabi SS, Yoshino M, Yoshino J, Cho K, Davila-Roman VG, Shankaran M, Barve RA, Yu J, Stern JH, Patterson BW, Hellerstein MK, Shulman GI, Patti GJ, Klein S. Cardiometabolic characteristics of people with metabolically healthy and unhealthy obesity. Cell Metab. 2024 Apr 2;36(4):745-761.e5. doi: 10.1016/j.cmet.2024.03.002.
Mittendorfer B, van Vliet S, Smith GI, Petersen MC, Patterson BW, Klein S. Impaired plasma glucose clearance is a key determinant of fasting hyperglycemia in people with obesity. Obesity (Silver Spring). 2024 Mar;32(3):540-546. doi: 10.1002/oby.23963. Epub 2024 Jan 16.
Seo JB, Riopel M, Cabrales P, Huh JY, Bandyopadhyay GK, Andreyev AY, Murphy AN, Beeman SC, Smith GI, Klein S, Lee YS, Olefsky JM. Knockdown of Ant2 Reduces Adipocyte Hypoxia And Improves Insulin Resistance in Obesity. Nat Metab. 2019 Jan;1(1):86-97. doi: 10.1038/s42255-018-0003-x. Epub 2018 Nov 19.
Ding X, Iyer R, Novotny C, Metzger D, Zhou HH, Smith GI, Yoshino M, Yoshino J, Klein S, Swaminath G, Talukdar S, Zhou Y. Inhibition of Grb14, a negative modulator of insulin signaling, improves glucose homeostasis without causing cardiac dysfunction. Sci Rep. 2020 Feb 25;10(1):3417. doi: 10.1038/s41598-020-60290-1.
Smith GI, Polidori DC, Yoshino M, Kearney ML, Patterson BW, Mittendorfer B, Klein S. Influence of adiposity, insulin resistance, and intrahepatic triglyceride content on insulin kinetics. J Clin Invest. 2020 Jun 1;130(6):3305-3314. doi: 10.1172/JCI136756.
Smith GI, Shankaran M, Yoshino M, Schweitzer GG, Chondronikola M, Beals JW, Okunade AL, Patterson BW, Nyangau E, Field T, Sirlin CB, Talukdar S, Hellerstein MK, Klein S. Insulin resistance drives hepatic de novo lipogenesis in nonalcoholic fatty liver disease. J Clin Invest. 2020 Mar 2;130(3):1453-1460. doi: 10.1172/JCI134165.
Cifarelli V, Beeman SC, Smith GI, Yoshino J, Morozov D, Beals JW, Kayser BD, Watrous JD, Jain M, Patterson BW, Klein S. Decreased adipose tissue oxygenation associates with insulin resistance in individuals with obesity. J Clin Invest. 2020 Dec 1;130(12):6688-6699. doi: 10.1172/JCI141828.
Beals JW, Smith GI, Shankaran M, Fuchs A, Schweitzer GG, Yoshino J, Field T, Matthews M, Nyangau E, Morozov D, Mittendorfer B, Hellerstein MK, Klein S. Increased Adipose Tissue Fibrogenesis, Not Impaired Expandability, Is Associated With Nonalcoholic Fatty Liver Disease. Hepatology. 2021 Sep;74(3):1287-1299. doi: 10.1002/hep.31822. Epub 2021 Jun 22.
Fuchs A, Samovski D, Smith GI, Cifarelli V, Farabi SS, Yoshino J, Pietka T, Chang SW, Ghosh S, Myckatyn TM, Klein S. Associations Among Adipose Tissue Immunology, Inflammation, Exosomes and Insulin Sensitivity in People With Obesity and Nonalcoholic Fatty Liver Disease. Gastroenterology. 2021 Sep;161(3):968-981.e12. doi: 10.1053/j.gastro.2021.05.008. Epub 2021 May 15.
Farabi SS, Smith GI, Schweitzer GG, Stein RI, Klein S. Do lifestyle factors and quality of life differ in people with metabolically healthy and unhealthy obesity? Int J Obes (Lond). 2022 Oct;46(10):1778-1785. doi: 10.1038/s41366-022-01180-6. Epub 2022 Jul 11.
Mittendorfer B, Patterson BW, Smith GI, Yoshino M, Klein S. beta Cell function and plasma insulin clearance in people with obesity and different glycemic status. J Clin Invest. 2022 Feb 1;132(3):e154068. doi: 10.1172/JCI154068.
Dunn JP, Lamichhane B, Smith GI, Garner A, Wallendorf M, Hershey T, Klein S. Dorsal striatal response to taste is modified by obesity and insulin resistance. Obesity (Silver Spring). 2023 Aug;31(8):2065-2075. doi: 10.1002/oby.23799.
Beals JW, Kayser BD, Smith GI, Schweitzer GG, Kirbach K, Kearney ML, Yoshino J, Rahman G, Knight R, Patterson BW, Klein S. Dietary weight loss-induced improvements in metabolic function are enhanced by exercise in people with obesity and prediabetes. Nat Metab. 2023 Jul;5(7):1221-1235. doi: 10.1038/s42255-023-00829-4. Epub 2023 Jun 26.
Other Identifiers
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PSQ-201512086
Identifier Type: -
Identifier Source: org_study_id
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