NutritionNCT03665948
Effect of Ketogenic and Carbohydrate Diet in Crossfit
A study testing Dietary Intervention - Ketogenic Diet (KD) and Dietary Intervention - Low-Glycemic Index Diet (CHO-LGI) in people with Nutrition and Ketogenic Dieting, run by Poznan University of Physical Education at 1 site in Poland.
Trial summary
The purpose of the presented study was to assess the influence of Ketogenic (KD) and a carbohydrate diet with a low glycemic index (CHO-LGI) of a 4-week diet on physical and specific performance capacity, exercise metabolism, as well as concentrations of the selected biochemical blood markers in Crossfit- trained… Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Nutrition, Ketogenic Dieting, Low Glycemic Index Diet
- What is being tested?
- Dietary Intervention - Ketogenic Diet (KD) and Dietary Intervention - Low-Glycemic Index Diet (CHO-LGI)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 70 participants
- Where
- 1 sitePoland
- Study dates
- 9 Jan 2017to 20 Dec 2024
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- written consent to participate,
- a current medical clearance to practice sports,
- training experience: at least 2 years,
- minimum of 4 workout sessions (Crossfit) a week.
Who cannot join
- current injury,
- any health-related contraindication,
- declared general feeling of being unwell,
- unwilling to follow the study protocol,
- smoking, illicit drug use, alcohol consumption greater than 1-2 drinks/week, dietary supplements use less than 3 weeks before the study,
- females- being pregnant or planning to become pregnant during the study.
Trial locations and contacts
1 site in 1 country.
Poland1 site
Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences
Poznan, 60-624
About this study
Official title: The Effect of Ketogenic and Carbohydrate, Low-Glycemic Index Diet on Physical and Specific Performance Capacity, and Exercise Metabolism in Crossfit- Trained Athletes
The purpose of the presented study was to assess the influence of Ketogenic (KD) and a carbohydrate diet with a low glycemic index (CHO-LGI) of a 4-week diet on physical and specific performance capacity, exercise metabolism, as well as concentrations of the selected biochemical blood markers in Crossfit- trained athletes, in a randomised and parallel trial.
Read the detailed description
The impact of various dietary strategies, including the alternative ketogenic diet - recently popular among strength athletes, has not been unequivocally assessed in the high-intensity sport disciplines that Crossfit belongs to. There is also a lack of data in these disciplines about the potential longer adaptation of athletes to the very low carbohydrate intake resulting from the ketogenic diet and its impact in high-intensity Crossfit training. Therefore, the purpose of this study was the assessment of the influence of a 4-week KD and a CHO-LGI diet on physical and specific performance capacity, exercise metabolism, as well as concentrations of the selected biochemical blood markers in Crossfit- trained athletes, in a randomised and parallel trial.
- Conditions
- Nutrition, Ketogenic Dieting, Low Glycemic Index Diet, Sport, Crossfit
- Being tested
- Dietary Intervention - Ketogenic Diet (KD), Dietary Intervention - Low-Glycemic Index Diet (CHO-LGI)
- Keywords
- Sports Nutrition, Ketogenic Diet, Low Glycemic Index Diet, Crossfit, Physical capacity, Performance, Exercise metabolism, Training support
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dietary Intervention - Ketogenic Diet (KD)Other
The experimental procedure for each randomly assigned participant included a 4-week of KD diet.
Dietary Intervention - Low-Glycemic Index Diet (CHO-LGI)Other
The experimental procedure for each randomly assigned participant included a 4-week of CHO-LGI diet.
| Study group | Role | What they receive |
|---|---|---|
| Ketogenic Diet (KD) | Experimental | Group consuming very low carbohydrate ketogenic diet. The ketogenic diet model was energetically normalized (covered the estimated energy expenditure) and assumed coverage of the daily energy requirement up to 5% of energy from carbohydrates. Proteins were administered in the amount of 1.7 g per kilogram of body mass. The remaining energy needs were covered with fats (fats covered more than 75% of the daily energy requirement). Each of the subjects in this group received 10-day menus. Receives: Other: Dietary Intervention - Ketogenic Diet (KD) |
| Low-Glycemic Index Diet (CHO-LGI) | Active comparator | Group consuming carbohydrate, low-glycemic index diet. The carbohydrate diet model with a low glycemic index was energetically normalized (covered the estimated energy expenditure) and assumed coverage of the daily energy requirement of 25% of fat. Proteins were administered in the amount of 1.7 g per kilogram of body mass. The remaining energy needs were covered with carbohydrates (carbohydrates covered about ~55% of the daily energy requirement). The glycemic index of individual meals as well as the daily diet was calculated in accordance with the appropriate recommendations. Each of the subjects in this group received 10-day menus. Receives: Other: Dietary Intervention - Low-Glycemic Index Diet (CHO-LGI) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in aerobic capacity following dietary intervention
Measured: Baseline and after 4 weeks
Changes in CrossFit-specific performance capacity (Fight Gone Bad test) following dietary intervention
The number of correctly performed repetitions of exercises (reps)
Measured: Baseline and after 4 weeks
Changes in energy substrates utilization following dietary intervention
Fats (g/min) and carbohydrates (g/min) oxidation analysis
Measured: Baseline and after 4 weeks
Secondary outcomes (6)
Changes in fat mass and fat free mass following dietary intervention
Fat mass (kg) and fat free mass (kg) analysis
Measured: Baseline and after 4 weeks
Changes of red and white blood cell concentration in blood following dietary intervention
Red blood cells (RBC) [mln/mm³] and white blood cells (WBC) [mln/mm³] concentration analysis
Measured: Baseline and after 4 weeks
Changes in blood glucose and hemoglobin concentration following dietary intervention
Hemoglobin (Hb) [g/dl] and glucose [g/dl] concentration analysis
Measured: Baseline and after 4 weeks
Changes in blood hematocrit levels following dietary intervention
Hematocrit (HCT) [%] level analysis
Measured: Baseline and after 4 weeks
Changes of testosterone, cortisol, urea, lactate and pyruvate concentration in blood following dietary intervention
Testosterone [mmol/L], cortisol [mmol/L], urea [mmol/L], lactate [mmol/L] and pyruvate [mmol/L] concentration analysis
Measured: Baseline and after 4 weeks
Changes of creatine kinase, lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activity in blood after following dietary intervention
Creatine kinase [U/L], lactate dehydrogenase [U/L], alanine aminotransferase [U/L] and aspartate aminotransferase [U/L] activity analysis
Measured: Baseline and after 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Sep 2018
- Study start9 Jan 2017
- Primary completion1 Nov 2024 (estimated)
- Study completion20 Dec 2024 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for NutritionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 70 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Poznan University of Physical Education
- Sponsor type
- University, hospital or other
- Collaborators
- Poznan University of PhysED, Poznan University of Life Sciences
- Responsible party
- Principal investigator, Krzysztof Durkalec-Michalski, Poznan University of Physical Education
- Investigators
- Jan Jeszka, Professor, Study chair, Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03665948
- Sponsor's protocol ID
- ULS00004
- Status last verified
- May 2024
- First submitted
- 5 Sep 2018
- Last updated
- 16 May 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: Shared data will be exclusively related to the level recorded indicators (anaerobic capacity and specific performance capacity indicators, exercise metabolism, levels of biochemical markers, and body composition), without personal data. The data obtained will be attached to scientific publications, depending on the requirements of the journal.
Publications
Durkalec-Michalski K, Nowaczyk PM, Siedzik K. Effect of a four-week ketogenic diet on exercise metabolism in CrossFit-trained athletes. J Int Soc Sports Nutr. 2019 Apr 5;16(1):16. doi: 10.1186/s12970-019-0284-9.
PubMed 30953522