The ability to walk to a nearby grocery store may be a crucial factor in determining how much weight a patient loses over the long run after bariatric surgery.

Nevertheless, researchers discovered that merely residing near a food shop isn't a surefire route to long-term weight loss, especially if the market serves largely processed convenience foods. The findings were published in Surgery for Obesity and Related Diseases and Obesity Surgery.

Overall, the analysis of data from hundreds of bariatric surgery patients in central Ohio showed an association between close proximity to food stores and better weight loss two years after the surgery.

A closer look at store products affected whether that proximity was beneficial, showing that living within a five-minute walk of a store with a low-quality selection of foods was actually linked to less weight loss at the two-year post-operative point.

"Being in closer proximity to lower-quality stores predicted less weight loss, but being in closer proximity to higher-quality stores didn't predict more weight loss," said Keeley Pratt, associate professor of human sciences at The Ohio State University and the lead author of two studies detailing these findings. "So the lower-quality stores were really driving poor outcomes."

The research team examined neighbourhood characteristics and other social determinants of health that may help or hinder continued weight loss in the two years after bariatric surgery.

The analysis included select data from the electronic health records of all patients who received bariatric surgery at The Ohio State University Wexner Medical Center from 2015 to 2019 in Franklin County, Ohio. Data included race, insurance type, procedure and percentage of total weight loss from two to 24 months after surgery.

Researchers combined health records with census and county data, which enabled the team to count not just the number of food stores, parks/recreational areas and fitness facilities in the county, but precisely where they were relative to patients' home addresses.

Bariatric surgery reduces the size of the stomach and leads to rapid weight loss, which requires patients to initially eat a soft diet in small quantities and gradually transition back to a more varied diet, being coached for six months by a dietitian and nurse practitioner.

"What we see then is from six months to a year and after a year, if that volume of food increases because of not maintaining healthy behaviours or returning to previously eaten foods that weren't as healthy, that weight can come back on," said Pratt, who also has a faculty appointment in general surgery.

"That being said, that doesn't mean that what patients can eat is readily available to them where they live - that's the link we're trying to figure out. Our patients know what to eat, so it's not an education or a knowledge issue, but it could be an access issue."