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

Study Overview
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Brief Summary
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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
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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.

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

Conditions
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Obesity, Diet Modification

Intervention / Treatment
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* Behavioral: Ketogenic diet
* Behavioral: Exercise HIIT


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The study subjects will be randomized into four study groups, one of which will be the control group.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ketogenic diet<br>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<br>* The study subjects randomized for this intervention will observe the ketogenic diet, as prescribed by the protocol.<br>|
| Experimental: Exercise HIIT (High-Intensity Interval Training)<br>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<br>* The study subjects randomized for this intervention will observe the HIIT exercise programme, as prescribed by the protocol.<br>|
| Experimental: Ketogenic diet + Exercise HIIT<br>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<br>* The study subjects randomized for this intervention will observe the ketogenic diet, as prescribed by the protocol.<br>Behavioral: Exercise HIIT<br>* The study subjects randomized for this intervention will observe the HIIT exercise programme, as prescribed by the protocol.<br>|
| No Intervention: Control Group<br>The study subjects in this arm will undergo no dietary changes and no exercise intervention. | |

What is the study measuring?
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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) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ketogenic diet, carbohydrates, chronic diseases, physical activity, fatigue, mood, wellbeing