Metabolic and Endocrine Effects of Bariatric Surgery

  • End date
    Jun 30, 2023
  • participants needed
  • sponsor
    Columbia University
Updated on 22 October 2022
bariatric surgery
gastric bypass
sleeve gastrectomy
calorie diet
Accepts healthy volunteers


The purpose of this study is to determine if diet-induced weight loss causes different changes in hormones that control appetite and glucose control than surgery-induced weight loss. The overall research plan is a non-randomized prospective study of 3 different weight loss (WL) interventions and a lean and an obese healthy control group.


Weight loss (WL) improves obesity-related co-morbidities such as type 2 diabetes mellitus (DM). Unfortunately, WL through life-style interventions has a high degree of relapse and the lack of safe, effective and affordable therapies together with an increase in the prevalence of morbid obesity has led to a rise in bariatric procedures. Clinical trials in patients with DM show that improvements in glycemia vary between procedures and occur in the following order: Roux-en-Y gastric bypass (RYGB) > sleeve gastrectomy (SG) > laparoscopic adjustable gastric banding (LAGB) > medical/life-style therapy. This order mirrors the amount of WL with each intervention and is a major driver of glycemic improvement. The investigators have shown profound changes unique to RYGB and SG in levels of hormones that make up the "gut-brain" and "enteroinsular" axes. The association of some of these hormones with insulin sensitivity (IS) and glycemia, independent of WL strongly suggests that glycemic improvements after surgery occur in part through pathways that are distinct from just calorie restriction. This study builds on results showing that levels of fibroblast growth factor 19 (FGF19), a protein secreted by intestinal cells, are increased after RYGB and SG but not after low calorie diet (LCD). This difference may affect hormones that control the stress response to weight loss. The investigators will explore differences in hormones of the gut that affect appetite, body weight, and stress response in healthy lean and obese individuals. Obese individuals will also be studied before and after 15% body weight loss induced by LCD, RYGB or SG, and again at 1 year after study enrollment.

Condition Insulin Resistance, Obesity
Treatment Very low calorie diet, Roux-en-Y Gastric Bypass, sleeve gastrectomy, Very low calorie diet (VLCD), Sleeve Gastrectomy (SG), Roux-en-Y Gastric Bypass (RYGBP)
Clinical Study IdentifierNCT03371368
SponsorColumbia University
Last Modified on22 October 2022


Yes No Not Sure

Inclusion Criteria

Men and women Ages 18-65 Years Old

Exclusion Criteria

Altered Sleep-wake Cycle
Type 1 or 2 Diabetes
Previous Bariatric Surgery
Lactose Intolerance
Any Special Diet restrictions
Use of medications that may affect body weight at screening or during a 3-month period prior
Untreated thyroid disease
Other medical conditions like Cushing's, acromegaly, Hearth failure, Crohn's disease, etc
Tobacco or opioid use
Alcohol dependence
> 3% weight change over the 3month period prior to screening
Unwillingness to maintain current level of physical activity over duration of study period
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