Clinical trial NCT06381908: The Effects of Combined Energy and Carbohydrate Restriction on Exercise Capacity
Official title: The Effects of Combined Energy and Carbohydrate Restriction on Exercise Capacity and Health in Overweight Women
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Overweight and Obesity
Keywords: Physical activity
Metabolism
Physical capacity
Macronutrients
Carbohydrate
Diet
Lead sponsor: University of Aarhus
Sponsor class: OTHER
Collaborators: name: University of Southern Denmark
name: University Ghent
First posted: 2024-04-24
Enrollment: 40
Sex: FEMALE
Minimum age (years): 20
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: The study is performed as a randomized single-blinded parallel group design. Randomization is performed into two groups using minimization based on a predetermined estimated VO2max middle value of 30.
Primary purpose: TREATMENT

Brief summary: The effect of calorie restriction combined with low or moderate carbohydrate availability on exercise capacity, metabolism and metabolic health indicators will be measured in a randomized parallel group design. Forty overweight (BMI 25-30) and relatively inactive women (20-35 of age) will be included. These will be randomized into one of two experimental groups both receiving a calorie-restricted diet (-1000 kcal) combined with either low carbohydrate availability or moderate carbohydrate availability across a 10 day period. Laboratory-based physical capacity tests and blood and muscle sampling will be performed before and after the intervention. In addition, an additional follow-up test day will be performed after continuing the diet for another 48 h and then standardizing the pre-testing carbohydrate availability before repeating the tests of physical capacity.

Detailed description: Overweight (BMI 25-30), but healthy premenopausal women aged 20-35 years (n=40) will be included in the trial, which is structured as a randomized, parallel group design where participants are randomized to either consume a hypocaloric diet (-1000 kcal) with concurrent carbohydrate restriction (low carbohydrate, L-CHO, n=20) or a similar hypocaloric diet with moderate carbohydrate availability (moderate carbohydrate, M-CHO, n=20). The trial will be single-blinded since it might be transparent to the participants which diet they are consuming, whereas the test personnel collecting and processing test results will be blinded to diet allocation. Diet handling will be managed by specific individuals in the research group who do not partake in executing the physical capacity tests. Additionally, the direction of the trial's primary hypothesis will not be disclosed to the participants to avoid creating preconceived expectations about the effects.

After an initial screening interview and two familiarization visits, participants will complete the intervention period consisting of 10 days with the allocated diet manipulation with preceding and subsequent test days with a series of tests. The tests before and after each test period include measurements of the participants' physical capacity level and energy metabolism in the laboratory as well as blood and muscle sampling. In addition, resting metabolism and body composition will be measured. During each test period, participants' habitual activity level will be monitored with an accelerometer attached to the wrist (Axivity). There will also be monitoring of the activity level with an accelerometer in a 7-day cycle before the start of the trial as a baseline measurement.

Similarly, a glucose monitor will be placed on the upper arm for continuous glucose readings via a Freestyle Libre2 sensor during the trial period.

Eligibility criteria: Inclusion Criteria:

* Age: 20-35
* BMI: 25-30

Exclusion Criteria:

* Irregular menstruation within the last 6 months (shorter end 24 days or longer end 35 days cycle)
* Injuries / pain in the lower body, which prevents participation in intense cycling
* Medication consumption that may affect primary outcome measures.
* Smoking
* Pregnancy
* Systematic physical activity more than 2 hours per week

Primary outcomes:
measure: Time to exhaustion
timeFrame: Pre, post (day 11 of the intervention) and follow-up (day 2 after the post measurement)
measure: Sprint performance
timeFrame: Pre, post (day 11 of the intervention) and follow-up (day 2 after the post measurement)
measure: Exercise tolerance
timeFrame: Pre, post (day 11 of the intervention) and follow-up (day 2 after the post measurement)
measure: Muscle glycogen levels
timeFrame: Pre and post (day 11 of the intervention)
Secondary outcomes:
measure: Physical activity level
timeFrame: During the intervention (days 1 to 11 of the intervention)
measure: Maximal fat oxidation capacity
timeFrame: Pre, post (day 11 of the intervention) and follow-up (day 2 after the post measurement)
measure: Muscle metabolic enzyme activity
timeFrame: Pre and post (day 11 of the intervention)
measure: Blood lipid profile
timeFrame: Pre and post (day 11 of the intervention)
measure: Continuous glucose levels
timeFrame: 14 days from the day before the intervention, throughout the intervention (days 1 to 11) and 2 days after the intervention (follow-up)
measure: Fasting blood glucose and insulin
timeFrame: Pre and post (day 11 of the intervention)
measure: Long-term glycemic control (HbAc1)
timeFrame: Pre and post (day 11 of the intervention)
Other outcomes:
Locations:
city: Aarhus C
country: Denmark
facility: Section for Sport Science, Department of Public Health, Aarhus University
Study officials:
References: