Clinical trial NCT03665948: Effect of Ketogenic and Carbohydrate Diet in Crossfit
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
Study type: INTERVENTIONAL
Overall status: ACTIVE_NOT_RECRUITING
Phase: NA
Conditions: Nutrition
Ketogenic Dieting
Low Glycemic Index Diet
Sport
Crossfit
Keywords: Sports Nutrition
Ketogenic Diet
Low Glycemic Index Diet
Crossfit
Physical capacity
Performance
Exercise metabolism
Training support
Lead sponsor: Poznan University of Physical Education
Sponsor class: OTHER
Collaborators: name: Poznan University of PhysED
name: Poznan University of Life Sciences
First posted: 2018-09-11
Enrollment: 70
Sex: ALL
Minimum age (years): 18
Maximum age (years): 40
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief 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 athletes, in a randomised and parallel trial.

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.

Eligibility criteria: Inclusion Criteria:

* 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.

Exclusion Criteria:

* 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.

Primary outcomes:
measure: Changes in aerobic capacity following dietary intervention
timeFrame: Baseline and after 4 weeks
measure: Changes in CrossFit-specific performance capacity (Fight Gone Bad test) following dietary intervention
timeFrame: Baseline and after 4 weeks
measure: Changes in energy substrates utilization following dietary intervention
timeFrame: Baseline and after 4 weeks
Secondary outcomes:
measure: Changes in fat mass and fat free mass following dietary intervention
timeFrame: Baseline and after 4 weeks
measure: Changes of red and white blood cell concentration in blood following dietary intervention
timeFrame: Baseline and after 4 weeks
measure: Changes in blood glucose and hemoglobin concentration following dietary intervention
timeFrame: Baseline and after 4 weeks
measure: Changes in blood hematocrit levels following dietary intervention
timeFrame: Baseline and after 4 weeks
measure: Changes of testosterone, cortisol, urea, lactate and pyruvate concentration in blood following dietary intervention
timeFrame: Baseline and after 4 weeks
measure: Changes of creatine kinase, lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activity in blood after following dietary intervention
timeFrame: Baseline and after 4 weeks
Other outcomes:
Locations:
city: Poznań
country: Poland
facility: Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences
Study officials:
affiliation: Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences
name: Jan Jeszka, Professor
role: STUDY_CHAIR
References:
citation: 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.