protocolSection identificationModule nctId: NCT06325722, orgStudyIdInfo id: 10001680, secondaryIdInfos id: 001680-DK, briefTitle: Diet Order Effects of Low Fat vs. Low Carb Diets on Body Fat Change, statusModule overallStatus: NOT_YET_RECRUITING, startDateStruct date: 2024-05-01, primaryCompletionDateStruct date: 2026-07-31, completionDateStruct date: 2026-07-31, studyFirstPostDateStruct date: 2024-03-22, lastUpdatePostDateStruct date: 2024-04-26, sponsorCollaboratorsModule leadSponsor name: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), class: NIH, descriptionModule briefSummary: Background:In a previous study, participants were lived at the NIH and randomly received either a low-fat or a low-carbohydrate diet for 2 weeks and then switched to the other diet for 2 more weeks. Participants who received the low-carbohydrate diet first lost more body fat at the end of the study than those who received the low-fat diet first. Researchers want to see if they can repeat that result in a longer weight loss study when participants live at home.Objective:To test the effects of diet order in people receiving either a low-fat or low-carbohydrate diet first for 4 weeks and then immediately switched to the other diet for another 4 weeks.Eligibility:Adults aged 19 to 50 years with a body mass index of 25 or more.Design:Participants will complete the study at their homes, but there will be 3 required visits to the NIH. Participants will drink a special type of water 2 weeks before the baseline NIH visit and collect urine samples at home to measure how many calories they burn. Before the diets begin, participants will visit the NIH for baseline testing when they will have a metabolism test while relaxing in a bed with a plastic hood over their head to collect the air they breathe out. They will have scans to measure their bone density and how much muscle and body fat they have. They will give stool, blood, and urine samples.Participants will be asked to eat a specific diet for 4 weeks followed by a different diet for 4 weeks. All meals will be delivered to the participants homes. They will eat only the foods delivered.Participants will weigh themselves daily. They will wear a monitor to track their physical activity and a sensor to measure their glucose levels. They will prick their finger each morning to test a drop of blood for ketones. Participants will meet virtually as a group with the study team weekly. Participants will have two more NIH visits towards the end of each diet period...., conditionsModule conditions: Overweight, conditions: Obesity, designModule studyType: INTERVENTIONAL, phases: NA, designInfo allocation: RANDOMIZED, interventionModel: CROSSOVER, primaryPurpose: BASIC_SCIENCE, maskingInfo masking: SINGLE, whoMasked: PARTICIPANT, enrollmentInfo count: 100, type: ESTIMATED, armsInterventionsModule interventions name: Low-carbohydrate Diet, interventions name: Low-fat Diet, outcomesModule primaryOutcomes measure: Change in total fat mass, secondaryOutcomes measure: Rate of body weight change from baseline to week 8, secondaryOutcomes measure: Rate of body weight change during low-carbohydrate diet, secondaryOutcomes measure: Rate of body weight change during low-fat diet, eligibilityModule sex: ALL, minimumAge: 18 Years, maximumAge: 50 Years, stdAges: ADULT, contactsLocationsModule locations facility: National Institutes of Health Clinical Center, city: Bethesda, state: Maryland, zip: 20892, country: United States, contacts name: Kevin Hall, Ph.D., role: CONTACT, phone: 301-402-8248, email: kevinh@niddk.nih.gov, geoPoint lat: 38.98067, lon: -77.10026, hasResults: False