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

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.

Study Overview

• Status: Completed
• Conditions: Obesity; Diet Modification
• Intervention / Treatment: Behavioral: Ketogenic diet; Behavioral: Exercise HIIT

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 Type: Interventional
• Enrollment (Actual): 100
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Czechia
  • Moravian-Silesian Region
    • Ostrava, Moravian-Silesian Region, Czechia, 70103
      • University of Ostrava

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Ketogenic diet; Ketogenic diet: < 50 g carbohydrates - CHO/d (based on the 1-week pre-intervention habitual diet monitoring); protein restriction ≤ 1.5 g/kg free-fat mass (FFM)/day.; fat type intake recommendation:; natural fats; trans-FA reduction	Behavioral: Ketogenic diet; The study subjects randomized for this intervention will observe the ketogenic diet, as prescribed by the protocol.
Experimental: Exercise HIIT (High-Intensity Interval Training); Exercise intervention: - HIIT: 5 min warm-up - slow walking, 3 min interval of high-intensity walking (above VT2), 3 min interval of low-intensity walking (40 % VO2peak); 5 min cool-down - slow walking: Cycle 1; week 1-3 - 3 sessions/week, total time 31 min/session (4 intervals); week 4 - regeneration: only 2 sessions with 2 intervals, keep total time 31 min/session, (+ GXT) Cycle 2; week 5-7 - 3 sessions/week, total time 43 min/session (6 intervals); week 8 - regeneration: only 2 sessions with 4 intervals, total time 31 min/session, (+ GXT) Cycle 3; week 9-11 - 3 sessions/week, total time 55 min/session (8 intervals); week 12 - regeneration: only 2 sessions with 6 intervals, total time 43min/session, (+GXT)	Behavioral: Exercise HIIT; The study subjects randomized for this intervention will observe the HIIT exercise programme, as prescribed by the protocol.
Experimental: Ketogenic diet + Exercise HIIT; Ketogenic diet: < 50 g carbohydrates - CHO/d (based on the 1-week pre-intervention habitual diet monitoring); protein restriction ≤ 1.5 g/kg free-fat mass (FFM)/day.; fat type intake recommendation:; natural fats; trans-FA reduction Exercise intervention: - HIIT: 5 min warm-up - slow walking, 3 min interval of high-intensity walking (above VT2), 3 min interval of low-intensity walking (40 % VO2peak); 5 min cool-down - slow walking: Cycle 1; week 1-3 - 3 sessions/week, total time 31 min/session (4 intervals); week 4 - regeneration: only 2 sessions with 2 intervals, keep total time 31 min/session, (+ GXT) Cycle 2; week 5-7 - 3 sessions/week, total time 43 min/session (6 intervals); week 8 - regeneration: only 2 sessions with 4 intervals, total time 31 min/session, (+ GXT) Cycle 3; week 9-11 - 3 sessions/week, total time 55 min/session (8 intervals); week 12 - regeneration: only 2 sessions with 6 intervals, total time 43min/session, (+GXT)	Behavioral: Ketogenic diet; The study subjects randomized for this intervention will observe the ketogenic diet, as prescribed by the protocol.; Behavioral: Exercise HIIT; The study subjects randomized for this intervention will observe the HIIT exercise programme, as prescribed by the protocol.
No Intervention: Control Group; The study subjects in this arm will undergo no dietary changes and no exercise intervention.

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Biochemical analysis - capillary blood	All study subjects will undergo biochemical analysis of capillary blood - βHB and fasting glukose in mmol/L.	12 weeks (2 times/week)
Biochemical analysis - venous blood	All study subjects will undergo biochemical analysis of venous blood - oxidative stress, inflammation, total CHO, HDL, LDL, TG, FFA, GL, homocysteine, measured in mmol/L.	12 weeks (2 times/week)
Biochemical analysis - venous blood	All study subjects will undergo biochemical analysis of venous blood - HBA1c in mmol/mol.	12 weeks (2 times/week)
Anthropometrics - body height	All study subjects will undergo anthropometric assessment of the body height, measured in cm.	12 weeks (baseline + every four weeks)
Anthropometrics - body weight	All study subjects will undergo anthropometric assessment of the body weight, measured in kg.	12 weeks (baseline + every four weeks)
Anthropometrics - waist circumference	All study subjects will undergo anthropometric assessment of the waist circumference, measured in cm.	12 weeks (baseline + every four weeks)
Anthropometrics - DXA	All study subjects will undergo anthropometric assessment of DXA - total abdominal fat, measured in kg.	12 weeks (baseline + outcome)
InBody (bioimpedance)	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.	12 weeks (baseline + every four weeks)

Collaborators and Investigators

• Sponsor: University of Ostrava
• Investigators: Principal Investigator: Lukáš Cipryan, Ass.Prof.,PhDr.,PhD, University of Ostrava

Publications and helpful links

General Publications

• Cipryan L, Plews DJ, Ferretti A, Maffetone PB, Laursen PB. Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses. J Sports Sci Med. 2018 May 14;17(2):259-268. eCollection 2018 Jun.
• Cipryan L, Litschmannova M, Maffetone PB, Plews DJ, Dostal T, Hofmann P, Laursen PB. Very Low-Carbohydrate High-Fat Diet Improves Risk Markers for Cardiometabolic Health More Than Exercise in Men and Women With Overfat Constitution: Secondary Analysis of a Randomized Controlled Clinical Trial. Front Nutr. 2022 May 23;9:867690. doi: 10.3389/fnut.2022.867690. eCollection 2022.
• Cipryan L, Dostal T, Litschmannova M, Hofmann P, Maffetone PB, Laursen PB. Effects of a Very Low-Carbohydrate High-Fat Diet and High-Intensity Interval Training on Visceral Fat Deposition and Cardiorespiratory Fitness in Overfat Individuals: A Randomized Controlled Clinical Trial. Front Nutr. 2021 Dec 21;8:785694. doi: 10.3389/fnut.2021.785694. eCollection 2021.

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2018
• Primary Completion (Actual): December 31, 2019
• Study Completion (Actual): December 31, 2020

Study Registration Dates

• First Submitted: February 15, 2019
• First Submitted That Met QC Criteria: April 30, 2019
• First Posted (Actual): May 1, 2019

Study Record Updates

• Last Update Posted (Actual): January 25, 2021
• Last Update Submitted That Met QC Criteria: January 22, 2021
• Last Verified: January 1, 2020

More Information

Terms related to this study

• Keywords: physical activity; fatigue; ketogenic diet; carbohydrates; mood; wellbeing; chronic diseases
• Other Study ID Numbers: OU-PdF-GACR-LCHF diet; 18-08358S (Other Grant/Funding Number: GACR)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: The investigators have not decided to share the individual participant data with other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No