DIT After RYGB - A Prospective Study

Study Overview
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Brief Summary
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Bariatric surgery is the only satisfactory treatment for loss and weight maintenance in obese patients. This loss is a result of several factors that go beyond the simple anatomical abnormality of the gastrointestinal tract and may be the product of post-op energy expenditure changes. The respiratory quotient (RQ) and diet-induced thermogenesis (DIT) are important components of energy expenditure and possible changes in them can perform an important role in weight loss after Roux-en-Y Gastric Bypass (RYGB). Previously, we conducted a cross-sectional study where we measured the RQ and DIT in pre and post-op RYGB patients, which was published in the Surgery of Obesity and Related Diseases (SOARD) journal. The objective of this study is to perform a prospective analysis of these same variables (RQ and DIT), evaluating them in the same patients, when pre and postoperatively.

Official Title
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Diet-induced Thermogenesis After Roux-en-Y Gastric Bypass - A Prospective Study

Conditions
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Obesity, Morbid Obesity, Bariatric Surgery

Intervention / Treatment
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* Other: A standard mixed Meal


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pre-op: Body mass index (BMI) ≥ 40 kg/m2 or BMI ≥ 35 kg/m2 with associated co-morbidities. Age > 18 years Post-op: Patients who underwent surgery ≥ 12 months by the Head Surgeon of the Gastrocirurgia de Brasilia Clinic; Exclusion Criteria: Patients aged > 65 years. Severe heart and/or respiratory problems; Pregnant women.

Ages Eligible for Study
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Minimum Age: 18 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: Diagnostic
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: A standard mixed Meal<br>The standard mixed meal was composed of a chicken salad sandwich and 200ml of coconut water, totalling 260 kcal, distributed among carbohydrates (62%), proteins (12%) and lipids (26%). | Other: A standard mixed Meal<br>* All patients underwent an indirect calorimetry test, after a 12-h period of fasting from food and water, avoiding intake of alcohol or coffee, and avoiding physical exercise and cigarettes the day before the examination. To examine possible changes in the thermogenic effect of food, patients received a standard mixed meal (200 ml coconut water and a chicken salad sandwich using whole wheat bread). They then repeated the test 20 min and 60 min after eating to obtain a reading of the metabolic rate by considering DIT and the RQ in the postprandial period.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Post-op DIT increase | A post-op increase in DIT is expected to be greater than in pre-op period and may be a positive predictor for weight loss during the post-op phase. | 2 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Post-op RQ increase | A postprandial increase in RQ greater than that in the pre-op phase is expected showing improvement in carbohydrate metabolism after RYGB. | 2 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Diet-induced Thermogenesis;, Respiratory Quotient;, Roux-en-Y Gastric Bypass;, Energy Expenditure.