From here, biology can reassert itself. Courcoulas says the tiny pouch that serves as the new stomach expands slightly in most patients, perhaps increasing in size between 10 percent and 15 percent. If a stretch of intestine has been removed through surgery, the remaining portion may become more efficient in absorbing calories. For most, these changes result in just a slight "bounce" to a modestly higher weight.
But for some, this plateau period represents a danger zone. If a patient's eating and exercise habits have evolved, they can maintain this new weight. But if they have not, excess eating can cause what remains of the stomach to stretch significantly to accommodate more food -- thus leading to weight gain.
"If you tend to keep pushing yourself, taking one extra bite with every meal, then you can stretch the pouch," Jones said. "Over time you will eat more and more."
But Jones notes that more of a threat than the re-expansion of the stomach is simply eating too much of the wrong foods -- high-sugar, high-fat treats that pack a caloric punch sufficient to bring the weight back.
For this reason, counseling and other forms of psychological support are often seen as key to reaping the long-term health gains of weight loss surgery.
These benefits go far beyond a more attractive figure. For many morbidly obese patients, having such surgeries and maintaining a more normal weight can have a significant impact on their overall health and risk of early death.
"It is very important for these patients to receive behavioral therapy, as well as time with a nutritionist and a physical therapist," Jones said. "I can cut and sew, but it's really the nutritional and behavioral programs that help with patient success."
And along with professional help, maintaining personal motivation to keep the weight off is crucial.
"These are people who feel that they have failed at everything they tried in their lives," Courcoulas said. "If they feel that they are failing surgery, they're embarrassed and they don't want to come back for help."
"Regaining weight down the road is a common phenomenon for weight loss patients. These patients need to be educated and prepared for it if it happens."