Physiology of Weight Loss Surgery

https://doi.org/10.1016/j.suc.2011.08.009Get rights and content

Section snippets

Why (are people so fat?)

Several hypotheses and theories have been introduced to explain the origins of the current obesity epidemic. In 1962, a geneticist by the name of James V. Neel1 presented his theory of how the progress of natural human evolution favored the perpetuation of obesity and diabetes promoting “thrifty genes.”1 He proposed that those individuals who had thrifty genes were better able to extract nutrients from ingested food and were more efficient in accumulating fat during times of abundance, and this

How (does it all work?)

One of the earliest studies reporting on the effectiveness of surgery in treating obesity-related diseases (ie, diabetes) was first published in 1955. In this study, Friedman and colleagues9 reported observing “the amelioration of diabetes mellitus following subtotal gastrectomy.” Several decades later, Pories and colleagues10 reviewed their experience with gastric bypass surgery performed on obese patients and showed effective and durable weight loss (in a 14-year period) along with an 83%

Summary

Although the root cause of the current obesity epidemic has not been discovered, it warrants considerable attention and the appropriate use of all the treatment options available. As shown in Fig. 1, bariatric surgery is a proven and unrivaled treatment of obesity and the management of obesity-related diseases. Gastric bypass produces profound physiologic and metabolic changes in many organs as a result of surgical anatomic manipulation, as shown by the many studies available in the literature.

First page preview

First page preview
Click to open first page preview

References (78)

  • T.M. Barber et al.

    The incretin pathway as a new therapeutic target for obesity

    Maturitas

    (2010)
  • J.V. Neel

    Diabetes mellitus: a “thrifty” genotype rendered detrimental by “progress”?

    Am J Hum Genet

    (1962)
  • A.M. Prentice et al.

    Evolutionary origins of the obesity epidemic: natural selection of thrifty genes or genetic drift following predation release?

    Int J Obes

    (2008)
  • J.B. Speakman

    Thrifty genes for obesity, an attractive but flawed idea, and an alternative perspective: the ‘drifty gene’ hypothesis

    Int J Obes

    (2008)
  • K.M. Flegal et al.

    Prevalence and trends in obesity among US adults, 1999-2008

    JAMA

    (2010)
  • L. Sjöström et al.

    Effects of bariatric surgery on mortality in Swedish obese subjects

    N Engl J Med

    (2007)
  • H. Buchwald et al.

    Bariatric surgery: a systematic review and meta-analysis

    JAMA

    (2004)
  • D.R. Flum et al.

    Perioperative safety in the longitudinal assessment of bariatric surgery

    N Engl J Med

    (2009)
  • M.N. Frideman et al.

    The amelioration of diabetes mellitus following subtotal gastrectomy

    Surg Gynecol Obstet

    (1955)
  • W.J. Pories et al.

    Who would have thought it? An operation proves to be the most effective therapy for adult-onset diabetes mellitus

    Ann Surg

    (1995)
  • C.N. Ochner et al.

    Selective reduction in neural responses to high calorie foods following gastric bypass surgery

    Ann Surg

    (2011)
  • I. Sakata et al.

    Ghrelin cells in the gastrointestinal tract

    Int J Pept

    (2010)
  • D.E. Cummings et al.

    A preprandial rise in plasma ghrelin levels suggests a role in meal initiation in humans

    Diabetes

    (2001)
  • F. Diniz Mde et al.

    Bariatric surgery and the gut-brain communication–the state of the art three years later

    Nutrition

    (2010)
  • D.E. Cummings et al.

    Gastrointestinal regulation of food intake

    J Clin Investig

    (2007)
  • T.K. Hansen et al.

    Weight loss increases circulating levels of ghrelin in human obesity

    Clin Endocrinol

    (2002)
  • A.M. Wren et al.

    Gut hormones and appetite control

    Gastroenterology

    (2007)
  • P. Marzullo et al.

    The relationship between active ghrelin levels and human obesity involves alterations in resting energy expenditure

    J Clin Endocrinol Metab

    (2004)
  • T. Shiiya et al.

    Plasma ghrelin levels in lean and obese humans and the effect of glucose on ghrelin secretion

    J Clin Endocrinol Metab

    (2002)
  • P.J. English et al.

    Food fails to suppress ghrelin levels in obese humans

    J Clin Endocrinol Metab

    (2002)
  • N.A. Tritos et al.

    Serum ghrelin levels in response to glucose load in obese subjects post-gastric bypass surgery

    Obes Res

    (2003)
  • D.E. Cummings et al.

    Plasma ghrelin levels after diet-induced weight loss or gastric bypass surgery

    N Engl J Med

    (2002)
  • B. Oliván et al.

    Effect of weight loss by diet or gastric bypass surgery on peptide YY3-36 levels

    Ann Surg

    (2009)
  • R. Kelishadi et al.

    Short- and long-term relationships of serum ghrelin with changes in body composition and the metabolic syndrome in prepubescent obese children following two different weight loss programmes

    Clin Endocrinol

    (2008)
  • R. Morínigo et al.

    Short-term effects of gastric bypass surgery on circulating ghrelin levels

    Obes Res

    (2004)
  • G. Frühbeck et al.

    Fasting plasma ghrelin concentrations 6 months after gastric bypass are not determined by weight loss or changes in insulinemia

    Obes Surg

    (2004)
  • J.R. Shak et al.

    The effect of laparoscopic gastric banding surgery on plasma levels of appetite-control, insulinotropic, and digestive hormones

    Obes Surg

    (2008)
  • M. Faraj et al.

    Plasma acylation-stimulating protein, adiponectin, leptin, and ghrelin before and after weight loss induced by gastric bypass surgery in morbidly obese subjects

    J Clin Endocrinol Metab

    (2003)
  • C. Holdstock et al.

    Ghrelin and adipose tissue regulatory peptides: effect of gastric bypass surgery in obese humans

    J Clin Endocrinol Metab

    (2003)
  • Cited by (24)

    • Evidence for Neurocognitive Improvement After Bariatric Surgery: A Systematic Review

      2017, Psychosomatics
      Citation Excerpt :

      BS is more effective than medical treatment and lifestyle interventions for moderate and severe obesity, both in short- and long-term follow-up studies.51,52 Potential mechanisms for BS-related weight loss have included hypotheses related to changes in leptin, ghrelin, and insulin sensitivity.53,54 In general with weight loss, regardless of the method by which it is achieved, leptin levels seem to increase and there is some evidence that obese subjects may regain some leptin sensitivity, changing their neural response to food.45,53

    • Metabolic Predictors of Weight Loss After Bariatric Surgery

      2017, Metabolism and Pathophysiology of Bariatric Surgery: Nutrition, Procedures, Outcomes and Adverse Effects
    View all citing articles on Scopus

    Dr Alfonso Torquati is supported by National Institute of Health grant K23 DK075907.

    View full text