Clinical Trials Logo

Clinical Trial Summary

The present study is a parallel group design with randomised allocation to either a 1) reduced protein diet (RP) or a 2) normal protein diet (NP). The two groups will be pair-matched based on habitual dietary protein intake, endurance training, endurance performance, and sex. The aim of the study is to investigate the effects of reducing dietary protein (~1g protein/kg body mass) compared to an eucaloric normal protein diet (~2g protein/kg body mass) for 6 weeks in well-trained endurance athletes on endurance performance, body composition, skeletal muscle protein synthesis, and health-related outcomes. The hypothesis is that endurance performance will maintain or even be improved in well-trained endurance athletes after a 6-week dietary intervention of an eucaloric, protein reduced diet compared to a normal protein rich diet.


Clinical Trial Description

Design: The present study will include two phases: a 3-week run-in period, and a 6-week intervention of controlled diets containing either a reduced dietary protein (RP) or normal (habitual) protein (NP). The run-in period serves as a period for obtaining general activity data and habitual dietary and training habits in order to match the groups before entering the dietary intervention period. Subjects and dietary goals: The study is aiming at including 20 male endurance athletes exercising ~15hrs+/week. The 20 males will be pair-matched based on habitual endurance training, habitual dietary protein intake, and endurance performance, and allocated in a randomised order to: 1) a reduced-protein diet (RP) or 2) a normal-protein diet (NP). 3-weeks run-in period: After a minimum of 7 days after written consent has been obtained, the run-in period will begin. Habitual endurance training volumes will be registered in an online platform (TrainingPeaks) and daily activity level will be monitored using an accelerometer (SENS) throughout the run-in and diet intervention period. "Heavy water" (D2O) will be ingested in a large bolus (3.5ml/kg LBM) upon beginning of the run-in period and plasma enrichments will be maintained throughout the study period by ingesting small daily boluses. This serves to determine skeletal muscle protein synthesis throughout the study. 6-weeks dietary intervention: The diets will be eucaloric and the estimated energy percentages for macronutrients will be as follows: RP - Protein ~7E%, Carbohydrate ~63E%, Fat ~29E%. NP - Protein ~16E%, Carbohydrate ~53E%, Fat ~30E%. Weekly urine and faeces samples will be collected during the run-in period and dietary intervention and the controlled diets will be supplied weekly for the participants. Testing: Extensive endurance performance and metabolic testing will be performed prior to-, and during the intervention on weeks -1, 0 (Pre), 3 (Mid), and 6 (Post). The tests include: Body composition by DXA-scanning, resting metabolic rate by online respirometry using a Vyntus (Jaeger, PCX), venous blood-, and skeletal muscle biopsy sampling from m. Vastus Lateralis, a standardised breakfasts, endurance cycling on an electro-magnetically braked bike (Lode Excalibur) or running on a motorised treadmill (Woodway), and haemoglobin mass measuring using a modified version of the CO-rebreathing method. The body mass will be kept unchanged during the 6-weeks dietary intervention. ;


Study Design


Related Conditions & MeSH terms


NCT number NCT05426447
Study type Interventional
Source University of Copenhagen
Contact Bente Kiens, Professor
Phone +4535321619
Email bkiens@nexs.ku.dk
Status Recruiting
Phase N/A
Start date February 23, 2021
Completion date December 31, 2025

See also
  Status Clinical Trial Phase
Recruiting NCT06111040 - Nurturing Needs Study: Parenting Food Motivated Children N/A
Completed NCT06299072 - A Cross-sectional Online Survey Among Saudi Arabian Population in the Age Group 18-40 Years to Assess Whole Grain (WG) Awareness, Consumption Levels, and Dietary Habits Around Breakfast
Recruiting NCT05863559 - Super Chef - an Online Program Promoting the Mediterranean Dietary Pattern to Lower Income Families N/A
Active, not recruiting NCT04583683 - Effects of Very Low Calorie Diet vs Metabolic Surgery on Weight Loss and Obesity Comorbidities N/A
Not yet recruiting NCT06298253 - Behavioral Economics to Implement a Traffic Light Nutrition Ranking System: Study 2 N/A
Not yet recruiting NCT05783141 - Prebiotic Effects in Healthy Toddlers N/A
Not yet recruiting NCT05934968 - Mad Dog Cooking Class Series: Effects on Dietary Self-efficacy, Eating Behaviors and Health Outcomes N/A
Not yet recruiting NCT05526846 - Introducing a Plant-Based Diet for Patients Recovering From Colorectal Surgery N/A
Active, not recruiting NCT05544461 - Piloting a Web-based Personalised Nutrition App (eNutri) With UK University Students N/A
Active, not recruiting NCT04991142 - Models of Nutrition From Continuous Glucose Monitors
Recruiting NCT04946448 - COmbinAtion Therapy of dieT With biologicalS for Crohn's Disease: the OATS Study N/A
Recruiting NCT06318377 - Peanuts and Neurocognitive / Cardiovascular Health in Black Individuals N/A
Completed NCT04084028 - Cooking as a Health Behavior in College Students N/A
Terminated NCT04067362 - Chicory Fiber Effect on Satiety and GI Tolerance N/A
Recruiting NCT05512247 - Hearty Meals for Mom- Pilot Study of Meal Delivery for Cardiometabolic Health During Pregnancy N/A
Recruiting NCT06145009 - Time Restricted Eating, Eating Behaviors, and Cardiometabolic Risk in Emerging Adult Women N/A
Recruiting NCT06022302 - Effects of Changing Intestinal Transit Time on Gut Microbial Composition and Metabolism N/A
Completed NCT05173376 - SEP and the Impact of Portion Size on Daily Energy Intake N/A
Recruiting NCT04374747 - Fruit and Vegetable Intervention in Lactating Women to Reduce Breast Cancer Risk N/A
Recruiting NCT04876053 - Home Food Delivery for Diabetes Management in Patients of Rural Clinics N/A