In a previous post I have discussed the reasons that it can be so hard to answer questions about weight regain after sleeve gastrectomy and gastric bypass, however a recently published study gives us some of the best information we know so far about this question. The study reviewed a large number of Dutch patients undergoing bariatric surgery between 2015 and 2018, who’s outcomes were followed in a national registry. As they were looking at weight regain they firstly excluded all participants who lost less than 20% of their starting body weight during the first year. The groups were matched using a statistical method called propensity scoring that is able to match for other factors that can influence the outcome, so long as they are known and measured. The main outcomes the researchers looked at was the risk of people regaining more than 10% of their lost body weight. What they found was:
- 3.9% of patients undergoing Roux-en-Y gastric bypass and 11.1% of patients undergoing sleeve gastrectomy were excluded due to losing less than 20% of their starting body weight during the first year after surgery.
- Of those that lost at least 20% of their starting body weight, the risk of regaining at least 10% of their lost weight increased with time. i.e. weight after surgery tends to increase slowly with time.
- Of those that lost at least 20% of their starting body weight, 12.7% of people undergoing Roux-en-Y gastric bypass and 22.1% of people undergoing sleeve gastrectomy gained at least 10% of their lost weight by their last follow-up visit, up to five years after their surgery.
Overall this study provides some of the best evidence to date on the rates of weight regain after weight loss surgery. It is important to remember that the researchers were looking for people who gained more than 10% of their lost weight, which is still often a small amount of weight regain overall. Nevertheless this study does support the observation that weight regain after bariatric surgery is probably more common in people who have a sleeve gastrectomy than those who have a Roux-en-Y gastric bypass. Although risk of regaining weight is only one of a number of outcomes that are important to consider when choosing which operation to pick, if it is an important risk for you then please discuss this with your surgeon when making the choice of operation.