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Respiratory Quotient in Post Roux-en-Y Gastric Bypass Patients (RQ)

This study has been completed.
Information provided by (Responsible Party):
Silvia Leite Faria, Gastrocirurgia, Brazil Identifier:
First received: July 15, 2011
Last updated: September 7, 2012
Last verified: September 2012

Through the values of respiratory quotient (RQ) it is possible to estimate the utilization of energy substrates by the body, or if there is a higher or lower fat oxidation. Experimental and clinical studies have shown that after Roux-en-Y Gastric Bypass (RYGBP) there is a decrease in the values of RQ, which may be associated with increased lipid oxidation in the postoperative period.

Diet Induced Thermogenesis (DIT) is an important part of Total Energy Expenditure. We would like to know how it functions among RYGBP patients.

The purpose of this study is to evaluate the RQ and DIT of patients in the post operative phase and compare the result with a control group consisting of morbid obese population.

Condition Intervention
Morbid Obesity Other: breakfast (a chicken sandwich with juice)

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Cross-Sectional
Official Title: Respiratory Quotient in Post Roux-en-Y Gastric Bypass Patients

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

Primary Outcome Measures:
  • Diet Induced Thermogenesis [ Time Frame: 20min after standard meal ]
    To examine the possible changes in the thermic effect of food, the patients received a standard meal. They then repeated the test 20 minutes after eating to obtain a reading of the metabolic rate by considering the DIT and RQ in the postprandial period. DIT was calculated as the difference between post prandial metabolic rate and RMR.

Enrollment: 69
Study Start Date: May 2011
Study Completion Date: July 2011
Primary Completion Date: June 2011 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
bariatric patients
Bariatric post operative patients were compared with morbid obese population
Other: breakfast (a chicken sandwich with juice)
patients received a breakfast after de initial measurement
control group
morbid obese population


Ages Eligible for Study:   20 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
Bariatric post operative population

Inclusion Criteria (bariatric patients post-op)

  • With more than 1 year after surgery
  • Consent given to participate

Exclusion Criteria:

  • Pregnant women
  • Malnourished patients (anemia)
  • Tiroid disorders without treatment
  Contacts and Locations
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Please refer to this study by its identifier: NCT01396460

Gastrocirurgia de Brasilia
Brasilia, Distrito Federal, Brazil, 70390108
Sponsors and Collaborators
Gastrocirurgia, Brazil
  More Information

Responsible Party: Silvia Leite Faria, Silvia Leite Faria , MSc, RD, Gastrocirurgia, Brazil Identifier: NCT01396460     History of Changes
Study First Received: July 15, 2011
Last Updated: September 7, 2012

Keywords provided by Silvia Leite Faria, Gastrocirurgia, Brazil:
respiratory quotient
fat oxidation
morbid obesity
Bariatric Surgery

Additional relevant MeSH terms:
Obesity, Morbid
Nutrition Disorders
Body Weight
Signs and Symptoms processed this record on September 21, 2017