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DIT After RYGB - A Prospective Study (DIT RYGB)

This study has been completed.
Information provided by (Responsible Party):
Silvia Leite Faria, Gastrocirurgia, Brazil Identifier:
First received: December 14, 2012
Last updated: December 27, 2012
Last verified: December 2012
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.

Condition Intervention
Obesity Morbid Obesity Bariatric Surgery Other: A standard mixed Meal

Study Type: Interventional
Study Design: Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Diagnostic
Official Title: Diet-induced Thermogenesis After Roux-en-Y Gastric Bypass - A Prospective Study

Further study details as provided by Silvia Leite Faria, Gastrocirurgia, Brazil:

Primary Outcome Measures:
  • Post-op DIT increase [ Time Frame: 2 months ]
    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.

Secondary Outcome Measures:
  • Post-op RQ increase [ Time Frame: 2 months ]
    A postprandial increase in RQ greater than that in the pre-op phase is expected showing improvement in carbohydrate metabolism after RYGB.

Enrollment: 13
Study Start Date: August 2012
Study Completion Date: October 2012
Primary Completion Date: October 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: A standard mixed Meal
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
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.


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

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.
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Please refer to this study by its identifier: NCT01759667

Gastrocirurgia de Brasilia
Brasilia, Distrito Federal, Brazil, 70390-108
Sponsors and Collaborators
Silvia Leite Faria
Principal Investigator: Silvia L Faria, M.Science Gastrocirurgia de Brasilia
  More Information

Responsible Party: Silvia Leite Faria, Nutritionist, Master of Science in Human Nutrition, Gastrocirurgia, Brazil Identifier: NCT01759667     History of Changes
Other Study ID Numbers: 002
Study First Received: December 14, 2012
Last Updated: December 27, 2012

Keywords provided by Silvia Leite Faria, Gastrocirurgia, Brazil:
Diet-induced Thermogenesis;
Respiratory Quotient;
Roux-en-Y Gastric Bypass;
Energy Expenditure.

Additional relevant MeSH terms:
Obesity, Morbid
Nutrition Disorders
Body Weight
Signs and Symptoms processed this record on August 16, 2017