This is a relatively new approach. It is the first component of the duodenal switch operation and involves removing the lateral 2/3rds of the stomach with a stapling device. It can be done laparoscopically ( keyhole surgery) but is not reversible. It basically leaves a stomach tube instead of a stomach sack.
This is the first component of a BPD-DS where the stomach is reduced in size by removing the lateral 2/3rds leaving the stomach in the shape of a tube.
Sometimes it is offered to patients as part of a two stage Bypass operation particularly if they are super obese ( BMI>60) because it allows good weight loss until the patient gets down to a safe weight and the more radical bypass can then be offered laparoscopically when they are at a safer weight.
The residual stomach capacity is about 200mls so a generous entree should be possible.