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Post-Surgery Weight Regain: Hormonal and Metabolic Factors



sharma-obesity-guthormones2In yesterday’s post, I discussed the importance of dietary factors in weight regain after bariatric surgery.

In this post, I will discuss the role of hormonal and metabolic factors identified in our systematic review of post-surgical weight regain published in Obesity Surgery.

It is now widely assumed that the efficacy of bariatric surgery is not solely dependent on causing a “restriction” or simply “malabsorbtion” of calories.

Rather, there is now growing consensus that the key reason why bariatric surgery works is through its impact on gut hormones and neurological signals from the gut that significantly reduce hunger and/or satiety.

Thus, it is not surprising that in our review we found several studies that noted a significant relationship between post-surgical levels of the “hunger hormone” ghrelin and post-surgical weight regain. Patients who experienced less weight loss or greater weight regain after sleeve gastrectomy and/or roux-en-y bypass surgery demonstrated higher fasting and post-prandial ghrelin levels. Elevated ghrelin levels were also found to correlate with a return of hunger in patients with regain.

Other evidence points to the role of hypoglycaemia in promoting weight regain in some patients. Reactive hypoglycaemia after bariatric surgery may result from the rapid transit of ingested carbohydrates into the small intestine thereby generating an early and significant insulin surge which results in a reactive hypoglycaemia shortly after a meal. This would in turn prompt snacking and increased caloric ingestion resulting in weight regain.

While there is currently no medical treatment to deal with ghrelin elevations, the latter problem can potentially be managed by dietary measures, including the avoidance of high-glycemic index foods.

Given that there are many gut hormones that may be altered by bariatric surgery and their individual roles are still poorly understood, it is clear that we will need further studies to better understand how these factors may explain why some patients failure to lose weight after surgery or show a greater tendency for weight regain.

@DrSharma
Chicago, IL

ResearchBlogging.org
Karmali S, Brar B, Shi X, Sharma AM, de Gara C, & Birch DW (2013). Weight Recidivism Post-Bariatric Surgery: A Systematic Review. Obesity surgery PMID: 23996349

 

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4 Comments

  1. This is what exactly Dr Sharon Molaem discussed in his classical book” Survival of the sickest”.He had vehemently argued how any sickness has a survival value, including Diabetes and obesity .According to him in the present world of heavy food processing , obesity and diabetes are the price one has to pay for survival.I am glad that his theoretical assumption has been proved correct by this study..

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  2. Let’s also keep in mind that ghrelin does a lot more than simply affect appetite and hunger cues. It blocks the leptin receptor at the arcuate nucleus and also increases the metabolism-blocking neuropeptide, AGRP. It also blocks the MC4 receptor that regulates weight. So the metabolic impact of chronically elevated ghrelin and also low leptin that occurs post surgery effectively reduces the power of other pro-metabolism hormones, such as alpha-MSH needed for both appetite and weight control. Remember that chronic restrictive diets alter the metabolic hormones exactly in the way we are trying to avoid in these patients, i.e. increasing ghrelin and reducing leptin. This eventually leads to a diet-induced ‘defense of body weight’ and is ultimately not helpful with long term weight regulation.

    There actually are medical strategies that when used clinically do help create an improved balance between the metabolism blocking hormones, AGRP and Ghrelin and the pro-metabolism hormones leptin and MSH and in my experience clinically this does result in appetite and weight changes that are very favorable in post bariatric surgery patients. This involves targeting physiologic factors specifically.

    More published clinical research in this area is critically needed. Now that the physiology of obesity and appetite has become so much clearer over the past decade, it’s time to take findings from the research lab and apply what we know clinically. We have tools now that when applied thoughtfully are safe and effective and can help patients tremendously. Clinical research will help physicians understand how they can apply existing medications and the potential of key medications currently in the pipeline. This hopefully will bring surgeons and medical practitioners together to combine treatments where appropriate for even better long term results.

    As physicians, we can’t continue to ignore the importance/ requirement of balancing metabolic hormones medically rather than continuing to feel as though the patient’s only option is to further restrict diet and ramp up exercise loads which is known to be less than effective for most patients.

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  3. Very interesting and would love to hear more about this subject!!!!

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  4. @ Dr. Cooper…. what strategies?

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