Water Intake and Weight Control in Older Adults

Study Overview
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Brief Summary
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This study is a randomized controlled intervention trial in adults aged 50+ years with overweight or obesity, which will compare three groups with different diet prescriptions: 1) pre-meal water consumption (500 ml, before each main meal) with a hypocaloric diet; 2) 1500 ml water consumed throughout the day with a hypocaloric diet; 3) hypocaloric diet with no instructions regarding water consumption. Smart water bottles will objectively assess water intake timing and volume. Urine osmolality, urine volume, and serum osmolality will be used as objective indicators of compliance with the water intake prescription. We will investigate changes in perceived hunger and fullness and appetite-regulating hormones as potential mechanisms by which premeal water could improve appetite regulation. We will also investigate the impact of water consumption and hydration on executive function capabilities, which may influence intervention adherence. Although increasing water intake could be an effective weight management strategy, no evidence-based recommendations exist for the timing of water intake needed for this benefit.

Official Title
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Water Intake and Weight Control in Older Adults

Conditions
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Overweight and Obesity

Intervention / Treatment
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* Behavioral: Water intake and weight control in older adults - Premeal Water + hypocaloric diet
* Behavioral: Water intake and weight control in older adults - Total Daily Water + hypocaloric diet
* Behavioral: Water Intake and weight control in older adults - hypocaloric diet alone


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: aged 50+ years BMI 25-40 weight stable (+/- 2 kg) in past 6 months willing to provide consent and comply with study protocol Exclusion Criteria: usual plain drinking water intake >1500 ml/d uncontrolled hypertension (>159/99 mmHg) medical condition requiring specialized diet prescription (eg, T2D, CHF wih fluid restriction) medical condition that precludes participating in a physical activity program (eg, orthopedic injury) current or history of GI disease (eg, Crohn's), GI surgery, or medications which impact GI function allergies or aversions to foods included in the test meals

Ages Eligible for Study
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Minimum Age: 50 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Pre-meal water + Hypocaloric diet<br>premeal water ( 500 ml) before each main meal, three times per day + hypocaloric diet | Behavioral: Water intake and weight control in older adults - Premeal Water + hypocaloric diet<br>* Individuals will be randomly assigned to one of three groups. All individuals will receive counseling in a structured hypocaloric meal plan (1200-1500 kcal) that is consistent with a healthy dietary pattern as described by the Dietary Guidelines for Americans. This group will receive specific instructions for daily water intake timing and volume.<br>|
| Experimental: Daily water + Hypocaloric diet<br>total daily water prescription (1500 ml/d) + hypocaloric diet | Behavioral: Water intake and weight control in older adults - Total Daily Water + hypocaloric diet<br>* Individuals will be randomly assigned to one of three groups. All individuals will receive counseling in a structured hypocaloric meal plan (1200-1500 kcal) that is consistent with a healthy dietary pattern as described by the Dietary Guidelines for Americans. This group will receive specific instructions for total daily water intake.<br>|
| Active Comparator: Hypocaloric Diet alone<br>hypocaloric diet with not instructions regarding water intake | Behavioral: Water Intake and weight control in older adults - hypocaloric diet alone<br>* Individuals will be randomly assigned to one of three groups. All individuals will receive counseling in a structured hypocaloric meal plan (1200-1500 kcal) that is consistent with a healthy dietary pattern as described by the Dietary Guidelines for Americans. This group will receive instructions in the hypocaloric diet, without specific fluid intake recommendations.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body weight change | Body weight change in weight loss and weight loss maintenance phases | weeks 0 to 12 in the weight loss phase, month 0 to 12 post weight loss phase | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in appetite sensations | Changes in hunger and fullness, assessed using 100mm Visual Analog Scales (VAS), in weight loss and weight loss maintenance phases. These changes may mediate adherence to the hypocaloric diet and weight loss outcomes. | weeks 0 to 12 in the weight loss phase, month 0 to 12 post weight loss phase | 
| Change in hydration status | Changes in hydration status, assessed using urine and serum osmolality, urine specific gravity, and serum sodium, in weight loss and weight loss maintenance phases. These changes may mediate intervention adherence. | weeks 0 to 12 in the weight loss phase, month 0 to 12 post weight loss phase | 
| Change in executive function (EF) | Changes in EF (attention, inhibition) assessed using ePRIME computerized tasks, in weight loss and weight loss maintenance phases. These changes may mediate intervention adherence. | weeks 0 to 12 in the weight loss phase, month 0 to 12 post weight loss phase |