The Effects of Lowering Dietary Carbohydrates on Health, Exercise Performance and Wellbeing-related Outcomes

Not Applicable

Completed

• Conditions: Diet Modification; Obesity

• Registration Number: NCT03934476
• Lead Sponsor: University of Ostrava

Brief Summary

The aim of the study is to investigate the long-term effects of the ketogenic diet and exercise (including interactions) on health markers, exercise performance and wellbeing outcomes in sedentary overweight individuals.

Detailed Description

Intentional nutritional ketosis induced by the low carbohydrate diet is an intensively discussed topic of many scientific as well as non-scientific discussions throughout the areas of healthy living, the sports sciences and often used now for the prevention and treatment of chronic diseases. It has been demonstrated that long-term low-carbohydrate diet is more effective for weight loss and cardiovascular and metabolic risk factor reduction than a low-fat diet. In light of conflicting theories of best practice surrounding a polarized topic that impacts human health and daily work performance, the primary aim of this research project is to examine how low-carbohydrate ketogenic diets affect health markers, exercise performance and wellbeing outcomes in sedentary overweight individuals. Each study subject will be randomized into one of the four arms of the study and will undergo a 12-week intervention, with the exception of the study subjects in the control group, who will undergo no intervention for the period of 12 weeks.

The project outcomes are of immense importance for the investigator's global human health, focus on a unique holistic perspective and have the potential to contribute towards much-needed adjustments in public health recommendations.

Study Timeline

• Study Start: 2018-09-01
• Study First Submitted: 2019-02-15
• Study First Submitted QC: 2019-04-30
• Study First Posted: 2019-05-01
• Primary Completion: 2019-12-31
• Status Verified: 2020-01
• Study Completion: 2020-12-31
• Last Update Submitted: 2021-01-22
• Last Update Posted: 2021-01-25

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

• BMI 25.00 - 40.00 kg/m2
• non-smokers
• non-excessive alcohol intake (self-reported, ≥ to 2 drinks/day for men or ≥1 drink/day for women)
• willing to accept random assignment
• low active individuals over the last 1 year, i.e. no specific sports training or regular exercise (up to once a week) and self-reported physical activity < 150 min/week (IPAQ)
• no evidence of liver, renal, metabolic, and cardiopulmonary disease and dis-eases contraindicating physical activity, no cancer, no psychiatric illness
• Physical Activity Readiness Questionnaire (PAR-Q) pass
• body weight stable for the last 2 months and not actively on a weight loss plan
• prediabetes state allowed (impaired fasting glucose level, i.e. 5.6 - 6.9 mmol/l; HbA1c 5.7 - 6.4 %)

Exclusion Criteria

• pregnancy, lactation
• any specific diet (e.g. vegetarian)
• use of hypoglycemic, lipid-lowering, antihypertensive, psychiatric medications or medications known to affect body weight or energy expenditure; any medication not noted allowed if the individual had been stable while taking such medication for at least 3 months prior to baseline data collection

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Change in the time to exhaustion	12 weeks (baseline + every four weeks)	All study subjects will undergo the Graded Exercise Test, with measuring of the time to exhaustion in minutes.
Change in cardiorespiratory variables - oxygen consumption	12 weeks (baseline + every four weeks)	All study subjects will undergo the Graded Exercise Test, with measuring of the oxygen consumption (L/min).
Change in cardiorespiratory variables - heart rate	12 weeks (baseline + every four weeks)	All study subjects will undergo the Graded Exercise Test, with measuring of the heart rate (beats per minute).

Secondary Outcome Measures

Name	Time	Method
Biochemical analysis - capillary blood	12 weeks (2 times/week)	All study subjects will undergo biochemical analysis of capillary blood - βHB and fasting glukose in mmol/L.
Anthropometrics - body weight	12 weeks (baseline + every four weeks)	All study subjects will undergo anthropometric assessment of the body weight, measured in kg.
Anthropometrics - DXA	12 weeks (baseline + outcome)	All study subjects will undergo anthropometric assessment of DXA - total abdominal fat, measured in kg.
Biochemical analysis - venous blood	12 weeks (2 times/week)	All study subjects will undergo biochemical analysis of venous blood - HBA1c in mmol/mol.
InBody (bioimpedance)	12 weeks (baseline + every four weeks)	All study subjects will undergo antrhropometric assessment of bioimpedance using the InBody device showing the percentage of water and fat in the organism, measured in % of total body weight.
Anthropometrics - body height	12 weeks (baseline + every four weeks)	All study subjects will undergo anthropometric assessment of the body height, measured in cm.
Anthropometrics - waist circumference	12 weeks (baseline + every four weeks)	All study subjects will undergo anthropometric assessment of the waist circumference, measured in cm.

Trial Locations

Locations (1)

University of Ostrava; 🇨🇿 Ostrava, Moravian-Silesian Region, Czechia