Weight loss surgery can curb alterations in brain activity associated with obesity and improve cognitive function involved in planning, strategizing and organizing, according to a new study. Bariatric surgery is used to help people who are dangerously obese lose weight. Bariatric surgery procedures are designed to restrict the amount of food you can eat before you feel full by reducing the stomach's size or limit the absorption of nutrients by removing part of the small intestine from the path food takes through the digestive tract.