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Completed

NCT Number: NCT00939679

Effect of Gastric Bypass Surgery on Energy Metabolism

The purpose of this study is to investigate the short term and long term effects of Roux-en-Y gastric bypass (RYGB) surgery on energy expenditure, gastrointestinal and appetite regulating hormone levels, and appetite sensation. We hypothesize that following RYGB surgery, metabolism will be elevated in comparison to patients who have not yet had RYGB but who are losing weight simultaneously using a low calorie diet. We further hypothesize that this higher metabolism will be associated with alterations in fasting and postmeal levels of gastrointestinal and appetite regulating hormones. Long term (1.5 years after RYGB), we hypothesize that differences in metabolism, body composition, and hormone levels will distinguish between patients who have maintained their weight loss after RYGB vs those who have regained weight.

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Key information

Conditions

Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, Copenhagen, Denmark

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18-65
  • BMI ≥40, or ≥35 with concomitant obstructive sleep apnea, or hypertension
  • scheduled for RYGB surgery at Hvidovre Hospital, Copenhagen, Denmark
  • Must have lost between 1-4% body weight after 3 months of dietary counselling

Exclusion criteria

  • Deemed ineligible for RYGB surgery by patient's own physician(s)
  • Diabetes Mellitus
  • Non Caucasian
  • Weight >160kg (due to DEXA scanner limitations), or morphologically unable to accommodate in DEXA scanner (>40cm in maximum supine anterior-posterior dimension, or >60cm in maximum supine body width)
  • Hemoglobin <7.0 mmol/L
  • Psychiatric illness under the care of a psychiatrist
  • Eating disorder such as bulimia
  • Patients on special diets (eg vegetarian, Atkins)
  • Any history of thyroid dysfunction, or use of thyroid medication (with the exception of transient thyroiditis)
  • Hypothalamic or genetic etiology of obesity
  • A current diagnosis of cancer
  • Any surgery other than RYGB planned in the ensuing 3 months
  • Substance abuse or smoking
  • Use of prescription medications or over-the-counter drugs affecting metabolism
  • Excessive intake of alcohol (>7 drinks/week)
  • Excessive intake of caffeine (>300 mg/day)
  • Presence of any contraindication to use of a low calorie powder diet, including:
  • Past history of ventricular arrhythmias (even if treated)
  • Renal dysfunction (creatinine clearance <60 mL/min)
  • Liver enzymes (ALT or AST) >3x upper limit of normal
  • Milk protein allergy, or lactose intolerance
  • Porphyria or phenylketonuria
  • History of gout
  • Breastfeeding
  • Concomitant use of monoamine oxidase inhibitors or non potassium sparing diuretics
  • Inability or unwillingness to comply with a low calorie diet protocol
  • Patients who find the powder diet products to be unpalatable
  • Do not enjoy yogurt, carrots, or milk (as these are essential elements of the low calorie diet)

Treatment and study plan

Roux-en-Y gastric bypass surgery

Procedure

Briefly, RYGB is characterized first by creation of a small stomach pouch. The small intestine is then divided approximately 75 cm distal to the ligament of Treitz, creating a proximal intestinal limb that transports the secretions from the stomach remnant, liver, and pancreas, and a 'Roux' limb, that is attached to the new stomach pouch to drain consumed food. The distal end of the proximal limb is then reattached approximately 100 cm distal to the new stomach drainage site, creating a common channel where digestive enzymes mix with ingested food.

low calorie diet (1,000 kcal/day)

Dietary Supplement

Patients will consume a daily diet composed of:

  • 4 powder diet portions (Cambridge Diets, UK)
  • plain yogurt (100-125g)
  • skim milk (1L)
  • a limited variety of vegetables

The diet will be consumed by both groups for a 10 week period.

Other names: Cambridge Weight Plan, Northants, UK.

Primary outcomes

  1. Change in 24 hour energy expenditure

    Time frame: 7 weeks, 10 weeks (short term); 1.5 years (long term)

Secondary outcomes

  1. change in fasting bile acids and lipid profile

    Time frame: 7 weeks, 10 weeks (short term); 1.5 years (long term)

  2. changes in fasting levels of leptin, adiponectin, and visfatin

    Time frame: 7 weeks, 10 weeks (short term); 1.5 years (long term)

  3. change in body composition

    Time frame: 7 weeks, 10 weeks (short term); 1.5 years (long term)

  4. Change in appetite sensation

    Time frame: 7 weeks, 10 weeks (short term); 1.5 years (long term)

  5. change in fasting and postprandial levels of GLP-1, PYY, oxyntomodulin, glucose, insulin, C peptide, GIP, ghrelin, cholecystokinin

    Time frame: 7 weeks, 10 weeks (short term); 1.5 years (long term)

Sponsors and collaborators

Lead sponsor

University of Copenhagen

Other

Collaborators

  • Cambridge Weight Plan Limited

Registry information

Official study title

ERGEM: Effect of Roux-en-Y Gastric Bypass Surgery on Energy Metabolism.

Acronym: ERGEM

Important dates

Study start
2009
Primary completion
2013
Study completion
2013
First posted
Jul 15, 2009
Registry last updated
Aug 2, 2013

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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