The Effect of a Short-term Very Low Calorie Diet on Heart Rate Variability in Obese Individuals

Study Overview
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Brief Summary
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The purpose of this study is to determine whether short-term adherence to a very low calorie diet is effective in improving heart rate variability in obese individuals.

Official Title
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The Effect of Short-term Adherence to a Very Low Calorie Diet on Heart Rate Variability: a Pilot Randomised Controlled Trial in Obese Men and Women

Conditions
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Obesity

Intervention / Treatment
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* Dietary Supplement: Very low calorie diet
* Other: Standard weight loss diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy, non-smoking men and women Aged 32-65 years BMI 30-42 kg/m2 Exclusion Criteria: History of cardiovascular disease, diabetes, cancer, renal or liver disease or chronic gastrointestinal disorder Epileptic or history of fainting Adhered to a VLCD in the past 6 months History of drug or alcohol abuse including heavy drinking. Pregnancy, planning to get pregnant or breastfeeding Currently taking medications to control blood pressure Weight change of over 3kg in the past two months

Ages Eligible for Study
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Minimum Age: 32 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

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
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Very low calorie diet<br> | Dietary Supplement: Very low calorie diet<br> <br> * Other names: Lighterlife Total;|
| Active Comparator: Standard weight loss diet<br> | Other: Standard weight loss diet<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in 24 h SDNN (mean of the standard deviations of the normal-to-normal intervals) at day 7 | SDNN is a time domain parameter of overall heart rate variability | Baseline, day 7 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in night-time SDNN (mean of the standard deviations of the normal-to-normal intervals) at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime SDNN (mean of the standard deviations of the normal-to-normal intervals) at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h mean IBI (interbeat interval) at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time mean IBI (interbeat interval) at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime mean IBI (interbeat interval) at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h SDANN (standard deviations of the average normal-to-normal intervals calculated over periods of 5-minutes) at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time SDANN (standard deviations of the average normal-to-normal intervals calculated over periods of 5-minutes) at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime SDANN (standard deviations of the average normal-to-normal intervals calculated over periods of 5-minutes) at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h triangular index at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time triangular index at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime triangular index at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h RMSSD (root mean square of successive differences of normal-to-normal differences) at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time RMSSD (root mean square of successive differences of normal-to-normal differences) at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime RMSSD (root mean square of successive differences of normal-to-normal differences) at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h pNN50 (% differences between adjacent normal-to-normal intervals that are >50 ms) at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time pNN50 (% differences between adjacent normal-to-normal intervals that are >50 ms) at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime pNN50 (% differences between adjacent normal-to-normal intervals that are >50 ms) at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h LF (low frequency power) at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time LF (low frequency power) at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime LF (low frequency power) at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h HF (high frequency power) at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time HF (high frequency power) at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime HF (high frequency power) at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h LF/HF at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time LF/HF at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime LF/HF at day 7 |  | Baseline, day 7 | 
| Change from baseline in 24 h VLF (very low frequency power) at day 7 |  | Baseline, day 7 | 
| Change from baseline in night-time VLF (very low frequency power) at day 7 |  | Baseline, day 7 | 
| Change from baseline in daytime VLF (very low frequency power) at day 7 |  | Baseline, day 7 |