The purpose of the operation is to drastically decrease the amount of food eaten without causing hunger. Appetite is dramatically controlled by the restrictive effect of the new stomach, leading to an early feeling of fullness.

Candidates for laparoscopic sleeve gastrectomy must be at least 45 kg (100 lb) overweight, which is equivalent to having a BMI (Body Mass Index) of 40. Less overweight individuals, with a BMI of 35, may be considered candidates for surgery if they suffer from obesity-related comorbid conditions, such as diabetes, heart disease, hypertension, sleep apnea, pain in weight-bearing joints that interferes with daily life, etc.

Major surgical complications requiring a second operation to fix occur in about 1% of patients and include bleeding, infection, leakage, organ injury and intestinal obstruction. Risks from developing blood clots in the deep veins of the legs and the lungs are minimized by prophylactic blood thinner, leg pumps and early ambulation.
 
After surgery eating habits need to be adjusted to the smaller stomach capacity. Failure to control eating behaviors and repeated overeating may cause excessive vomiting, but usually only in the first few months following surgery.

When the degree of excess weight reaches the level of morbid obesity (BMI over 35-40), nonsurgical attempts at weight control fail 95% of the time. Surgical weight loss is currently the only effective and long-lasting method of weight control, with 85% success rate for laparoscopic gastric bypass operation. Other less effective operations, including laparoscopic gastric banding and sleeve gastrectomy, are not recommended.