Effect of Ketogenic and Carbohydrate Diet in Crossfit

Not Applicable

Active, not recruiting

• Conditions: Ketogenic Dieting; Low Glycemic Index Diet; Nutrition; Sport; Crossfit

• Registration Number: NCT03665948
• Lead Sponsor: Poznan University of Physical Education

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.

Study Timeline

• Study Start: 2017-01-09
• Study First Submitted: 2018-09-05
• Study First Submitted QC: 2018-09-07
• Study First Posted: 2018-09-11
• Status Verified: 2024-05
• Last Update Submitted: 2024-05-14
• Last Update Posted: 2024-05-16
• Primary Completion: 2024-11-01
• Study Completion: 2024-12-20

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 70

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Changes in energy substrates utilization following dietary intervention	Baseline and after 4 weeks	Fats (g/min) and carbohydrates (g/min) oxidation analysis
Changes in aerobic capacity following dietary intervention	Baseline and after 4 weeks
Changes in CrossFit-specific performance capacity (Fight Gone Bad test) following dietary intervention	Baseline and after 4 weeks	The number of correctly performed repetitions of exercises (reps)

Secondary Outcome Measures

Name	Time	Method
Changes in blood glucose and hemoglobin concentration following dietary intervention	Baseline and after 4 weeks	Hemoglobin (Hb) \[g/dl\] and glucose \[g/dl\] concentration analysis
Changes of testosterone, cortisol, urea, lactate and pyruvate concentration in blood following dietary intervention	Baseline and after 4 weeks	Testosterone \[mmol/L\], cortisol \[mmol/L\], urea \[mmol/L\], lactate \[mmol/L\] and pyruvate \[mmol/L\] concentration analysis
Changes in fat mass and fat free mass following dietary intervention	Baseline and after 4 weeks	Fat mass (kg) and fat free mass (kg) analysis
Changes of red and white blood cell concentration in blood following dietary intervention	Baseline and after 4 weeks	Red blood cells (RBC) \[mln/mm³\] and white blood cells (WBC) \[mln/mm³\] concentration analysis
Changes in blood hematocrit levels following dietary intervention	Baseline and after 4 weeks	Hematocrit (HCT) \[%\] level analysis
Changes of creatine kinase, lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase activity in blood after following dietary intervention	Baseline and after 4 weeks	Creatine kinase \[U/L\], lactate dehydrogenase \[U/L\], alanine aminotransferase \[U/L\] and aspartate aminotransferase \[U/L\] activity analysis

Trial Locations

Locations (1)

Institute of Human Nutrition and Dietetics, Poznan University of Life Sciences; 🇵🇱 Poznań, Poland