[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-study-detail:100656710":3},{"organization":4,"outcomesModule":7,"designInfo":29,"detailedDescription":39,"studyPopulation":28,"armGroups":40,"interventions":58,"overallOfficials":72,"centralContacts":76,"locations":84,"responsibleParty":103,"collaborators":28,"id":105,"slug":106,"hasResults":107,"nctId":108,"briefTitle":109,"officialTitle":110,"acronym":111,"eligibilityCriteria":112,"healthyVolunteers":113,"sex":114,"minAge":115,"maxAge":116,"enrollmentInfo":117,"targetDuration":28,"studyType":120,"phases":121,"briefSummary":123,"conditions":124,"keywords":126,"overallStatus":87,"whyStopped":28,"lastUpdateSubmitDate":133,"lastUpdatePostDateStruct":134,"startDateStruct":137,"completionDateStruct":139,"leadSponsor":141,"locationsCount":142},{"fullName":5,"class":6},"University of Toronto","OTHER",{"primaryOutcomes":8,"secondaryOutcomes":23,"otherOutcomes":28},[9,13,17,20],{"measure":10,"description":11,"timeFrame":12},"Whole-body carbohydrate oxidation","Whole-body carbohydrate oxidation will be calculated from oxygen consumption (VO2) and carbon dioxide production (VCO2) measured by indirect calorimetry during 90 minutes of moderate-intensity cycling. Carbohydrate oxidation will be compared between the carbohydrate, protein, and fasted conditions and between females and males.","During the 90-minute exercise bout",{"measure":14,"description":15,"timeFrame":16},"Whole-body fat oxidation","Whole-body fat oxidation will be calculated from VO2 and VCO2 measured by indirect calorimetry during 90 minutes of moderate-intensity cycling. Fat oxidation will be compared between the carbohydrate, protein, and fasted conditions and between females and males.","During the 90-min exercise bout",{"measure":18,"description":19,"timeFrame":16},"Exogenous glucose oxidation","Exogenous glucose oxidation will be determined during the carbohydrate condition using breath 13CO2 enrichment following ingestion of \\[U-13C6\\]-D-glucose. Breath samples will be analyzed by isotope ratio mass spectrometry, and exogenous glucose oxidation will be calculated using 13CO2 enrichment and carbon dioxide production.",{"measure":21,"description":22,"timeFrame":16},"Exogenous leucine oxidation","Exogenous leucine oxidation will be determined during the protein condition using breath ¹³CO₂ enrichment following ingestion of L-\\[1-¹³C\\]leucine. Breath samples will be analyzed by isotope ratio mass spectrometry, and exogenous leucine oxidation will be calculated using breath ¹³CO₂ enrichment and carbon dioxide production.",[24],{"measure":25,"description":26,"timeFrame":27},"Time to task failure","Exercise performance will be assessed as time to volitional exhaustion during a cycling time-to-task-failure test performed at 85% of maximal work rate following the 90-minute moderate-intensity cycling bout.","Immediately following the 90-min exercise bout",null,{"allocation":30,"interventionModel":31,"interventionModelDescription":32,"primaryPurpose":33,"observationalModel":28,"timePerspective":28,"maskingInfo":34},"RANDOMIZED","CROSSOVER","Each participant will complete three pre-exercise nutrition conditions (carbohydrate, protein, and fasted\u002Fplacebo) in a randomized, counterbalanced order, with a minimum 3-day washout period between conditions.","BASIC_SCIENCE",{"masking":35,"maskingDescription":28,"whoMasked":36},"DOUBLE",[37,38],"PARTICIPANT","INVESTIGATOR","Sex differences in substrate utilization during fasted endurance exercise are well established, with females generally demonstrating greater reliance on fat oxidation and lower carbohydrate utilization than males. However, exercise is frequently performed following nutrient ingestion, and it remains unclear whether sex differences in substrate utilization persist when carbohydrate or protein is consumed before exercise.\n\nThis randomized, counterbalanced crossover study will compare three pre-exercise nutritional conditions: carbohydrate (CHO), protein (PRO), and fasted\u002Fplacebo (FAST). Participants will complete each condition separated by a minimum three-day washout. Following an overnight fast, participants will consume the assigned beverage and rest for 30 minutes before completing 90 minutes of cycling at 65% of VO2peak. This will be followed by a two-minute rest and a cycling time-to-task-failure test at 85% of maximal work rate.\n\nThe primary objective is to determine whether pre-exercise nutrition modifies sex differences in whole-body carbohydrate and fat oxidation and exogenous substrate oxidation during exercise. A secondary objective is to determine the effects of pre-exercise nutrition and sex on subsequent exercise performance.",[41,47,52],{"label":42,"type":43,"description":44,"interventionNames":45},"Carbohydrate (CHO)","EXPERIMENTAL","Participants will consume a carbohydrate beverage following an overnight fast. Thirty minutes after beverage consumption, participants will complete 90 minutes of cycling at 65% of VO2peak, followed by a 2-minute rest and a cycling time-to-task-failure test at 85% of maximal work rate.",[46],"Dietary Supplement: Pre-exercise carbohydrate beverage",{"label":48,"type":43,"description":49,"interventionNames":50},"Protein (PRO)","Participants will consume a protein-based beverage following an overnight fast. Thirty minutes after beverage consumption, participants will complete 90 minutes of cycling at 65% of VO2peak, followed by a 2-minute rest and a cycling time-to-task-failure test at 85% of maximal work rate.",[51],"Dietary Supplement: Pre-exercise protein beverage",{"label":53,"type":54,"description":55,"interventionNames":56},"Fasted (FAST)","PLACEBO_COMPARATOR","Participants will remain fasted and consume a non-caloric, flavour-matched beverage. Thirty minutes after beverage consumption, participants will complete 90 minutes of cycling at 65% of VO2peak, followed by a 2-minute rest and a cycling time-to-task-failure test at 85% of maximal work rate.",[57],"Other: Fasted control beverage",[59,64,68],{"type":60,"name":61,"description":62,"armGroupLabels":63,"otherNames":28},"DIETARY_SUPPLEMENT","Pre-exercise carbohydrate beverage","A carbohydrate beverage providing 1 g glucose\u002Fkg body mass, enriched with 1 mg\u002Fkg body mass \\[U-13C6\\]-D-glucose for assessment of exogenous carbohydrate oxidation, with calorie-free flavouring. The beverage will be consumed within 5 minutes, 30 minutes before exercise.",[42],{"type":60,"name":65,"description":66,"armGroupLabels":67,"otherNames":28},"Pre-exercise protein beverage","A protein-based beverage providing 0.45 g protein\u002Fkg body mass and supplemented with 0.24 g fat\u002Fkg body mass to match the energy content of the carbohydrate condition. The beverage is enriched with L-\\[1-13C\\]leucine and flavour-matched to the carbohydrate beverage. It will be consumed within 5 minutes, 30 minutes before exercise.",[48],{"type":6,"name":69,"description":70,"armGroupLabels":71,"otherNames":28},"Fasted control beverage","A non-caloric beverage consisting of water and sugar-free flavouring, flavour-matched to the carbohydrate beverage. The beverage will be consumed within 5 minutes following an overnight fast, 30 minutes before exercise.",[53],[73],{"name":74,"affiliation":5,"role":75},"Jenna Gillen, PhD","PRINCIPAL_INVESTIGATOR",[77,81],{"name":74,"role":78,"phone":79,"phoneExt":28,"email":80},"CONTACT","4169783244","jenna.gillen@utoronto.ca",{"name":82,"role":78,"phone":79,"phoneExt":28,"email":83},"Victoria Bennett","victoria.bennett@mail.utoronto.ca",[85],{"facility":86,"status":87,"city":88,"state":89,"zip":90,"country":91,"countryCode":92,"cosmosGeoPoint":93,"geoPoint":98,"contacts":99},"Goldring Centre for High Performance Sport","RECRUITING","Toronto","Ontario","M5S 2C9","Canada","CA",{"type":94,"coordinates":95},"Point",[96,97],-79.39864,43.70643,{"lat":97,"lon":96},[100,102],{"name":101,"role":78,"phone":79,"phoneExt":28,"email":80},"Jenna Gillen",{"name":82,"role":78,"phone":79,"phoneExt":28,"email":83},{"type":75,"investigatorFullName":101,"investigatorTitle":104,"investigatorAffiliation":5,"oldNameTitle":28,"oldOrganization":28},"Associate Professor","100656710","fuel-use-during-exercise-in-males-and-females-100656710",false,"NCT07829237","FueL Use During eXercise in Males and Females","Influence of Pre-exercise Nutrition on Exercise Fuel Use in Males and Females","FLUX","Inclusion Criteria:\n\n* Participating in ≥150 minutes of moderate-to-vigorous physical activity per week\n* VO₂peak classified as \"good\" or above based on American College of Sports Medicine normative values: \\>35.0 mL\u002Fkg\u002Fmin for females and \\>39.0 mL\u002Fkg\u002Fmin for males\n* Body mass index (BMI) between 18 and 27 kg\u002Fm²\n* Participating in 3-5 structured exercise sessions per week\n* Weight stable, defined as within ±2 kg for at least 6 months\n* Non-smoker\n* Females must be eumenorrheic\n\nExclusion Criteria:\n\n* Polycystic ovarian syndrome (PCOS) or endometriosis Current use of oral contraceptives or oral contraceptive use within the previous 3 months Diagnosed cardiovascular or metabolic disease Hypergonadism or hypogonadism Use of medications for management of blood glucose or lipid metabolism Pregnant or \\\u003C12 months postpartum Lactating or breastfeeding within 3 months of study commencement Menopausal Recreational tobacco smoking Inability to complete the study exercise protocols or comply with pre-trial dietary or physical activity controls Use of medications that may affect substrate metabolism, including corticosteroids or non-steroidal anti-inflammatory drugs (NSAIDs) Currently following a low-carbohydrate diet, such as a ketogenic or Atkins diet",true,"ALL","18 Years","35 Years",{"count":118,"type":119},24,"ESTIMATED","INTERVENTIONAL",[122],"NA","This study will investigate whether pre-exercise nutrition influences sex differences in fuel utilization during endurance exercise. Twenty-four recreationally active adults (12 females and 12 males) will complete three experimental exercise trials in a randomized, counterbalanced crossover design. Before each trial, participants will consume either a carbohydrate beverage, a protein-based beverage, or a flavour-matched non-caloric beverage representing the fasted condition. Thirty minutes later, participants will complete 90 minutes of moderate-intensity cycling followed by a cycling time-to-task-failure test. Whole-body carbohydrate and fat oxidation, exogenous substrate oxidation, blood metabolites, and exercise performance will be assessed.",[125],"Healthy Adults",[127,128,129,130,131,132],"exercise metabolism","substrate oxidation","exercise","nutrition","protein","carbohydrate","2026-09-14",{"date":135,"type":136},"2026-09-18","ACTUAL",{"date":138,"type":119},"2026-09-30",{"date":140,"type":119},"2027-06-30",{"name":5,"class":6},1]