Article Review: Metabolic remission precedes possible weight regain after gastric bypass surgery
Roux-en-Y gastric bypass surgery (RYGB) is a surgical intervention that creates a small pouch in the upper stomach and connects that directly to the jejunum (a part of the large intestine). This in turn bypasses the lower stomach and the upper portion of the large intestine which creates a smaller area for food digestion, resulting in people feeling full faster and reducing their overall caloric intake.
Gastric bypass, specifically RYGB is marketed to help lose excessive weight and reduce risk of cardiovascular disease, cancer, and type 2 diabetes. However, it is also known that people who receive gastric bypass surgery do regain weight after surgery.
"87% regain weight within 5 years post surgery, though not reaching preoperative levels."
One of the major benefits of RYGB is that 80% of cases have remission of their type 2 diabetes and another 10% of cases have improved glycemic control. The question on many researchers minds is when do the metabolic changes occur and do they last.
A recent study from March of 2023 has new evidence that supports the beneficial metabolic changes produced after gastric bypass surgery do come prior to weight regain. The majority of metabolic effects occur within 6 weeks post surgery, at this time they tend to level off.
What the data shows-
Diabetes Specific Findings:
HbA1c levels decreased during the first 12 months, but did increase slightly in the following 12 months.
Blood glucose levels decreased during the first 2 months post surgery and remained at this new level for the rest of the study.
88% of participants with type 2 diabetes prior to surgery no longer required glucose-lowering medications 1 year post surgery.
Other Findings-
Changes in Lipid levels were observed in the first 2 months, but then reversed in the following 10 months; overall little effects observed 1 year post surgery.
Medium and long-chain acetylcarnitines (a type of lipid) increased 2 months post surgery, but reversed in the next 10 months; again little overall change was observed.
It is known that longer-chain acetylcarnitines that are unsaturated are protective against diabetes, so it does seem like the increased numbers should remain long-term. However, in this study it is believed that the increased numbers are not from a general shift or changes in processing, but instead the increased lipolysis related to the rapid weight loss causing an overload in the body.
Reduction in sugars and sugar-related metabolites and increased levels of ketone bodies 2 months post surgery.
This is likely due to the fact that fat stores are being used as the main energy source during this time rather than ingested carbs. It is expected to see these changes soon after surgery.
Overall, the studies findings do support the protective role of RYGB on diabetes risk, but it is suggested that the protection levels off after as little as 1 year post surgery. This emphasizes the need for continued support with diet and exercise to maintain the protective factors. The surgery can not be the only intervention, it needs to be the starting block. Working with a dietitian throughout the post surgical phase to create and maintain healthy habits can be key to maintaining metabolic remission and reducing weight regain in the long-run.
Written by: Meghan Hawley, RD. Ellen Byron and Associates.
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