How Effective is Weight Loss Surgery?

Weight loss surgery is the most effective and lasting treatment currently available for treating severe obesity. The condition of severe obesity causes metabolic changes that makes the body resistant to meaningful and maintainable weight loss, yet surgical treatment has proven to be a successful option. It has helped hundreds of thousands of patients achieve significant, lasting weight loss results and substantial improvements to overall health and quality of life.

Bariatric Surgery Results
Choosing to undergo weight loss surgery is a big decision. It is important for you to learn about your options and have realistic expectations.

If you are considering weight loss surgery, the following information will highlight the factors affecting weight loss surgery results, expected outcomes of the various types of weight loss surgery, and briefly explain how these weight loss procedures will help you lose excess weight.

Proven Results

The successful results that can be achieved with weight loss surgery has been proven in numerous studies. Surgery alone is not a miracle solution to losing weight, but it is a tool that can be used to make success possible.

Studies have shown:

  • Diets, exercise, behavioral modification, and drugs are not effective in individuals with severe obesity; on average, long-term weight loss is only 5-10% with these methods.
  • The vast majority of individuals previously affected by severe obesity are able to maintain an excess weight loss of 50% or more (i.e. success) following weight loss surgery.
  • Bariatric surgery produces durable weight loss exceeding 100 pounds.
  • Bariatric surgery leads to remission of type 2 diabetes in 4 out of 5 patients.
  • Bariatric surgery improves health, improves quality of life, and extends longevity.

Excess weight loss (i.e. current weight - ideal body weight = excess weight) is the preferred method of reporting results because of gender variations and great variations in weight among operated individuals. It also allows for some comparison between bariatric procedures.

The ample evidence to date has lead the National Institutes of Health (NIH) to conclude:

  • The most effective means currently available to induce substantial weight loss, with long-term maintenance of that weight loss, is through bariatric surgery.

Factors Affecting Results of WLS

The effectiveness and durability of weight loss surgery is something which will vary among individuals. Some of the primary factors affecting both short and long-term results include:

  • patient age, gender, race, and body composition
  • pre-operative weight/body mass index
  • pre-operative health status/medical conditions
  • type of weight loss surgery performed
  • adherence to dietary and nutritional guidelines
  • amount of physical activity following surgery
  • participation in a multi-disciplinary bariatric program
  • keeping scheduled follow-up appointments

A study released in 2008 examining the effects of bariatric surgery made the following observations about patients factors and weight loss results:

  • "In general, younger patients, females, Caucasians, muscular and highly motivated individuals who follow an exercise program, patients who return for scheduled follow-up, and those who comply with the recommendations for vitamin/mineral supplements and do not snack will lose the most weight."

(Source Reference: Pories WJ. Bariatric Surgery: Risks and Rewards. The Journal of Clinical Endocrinology and Metabolism. 2008;93(11 Suppl 1):S89-S96. doi:10.1210/jc.2008-1641.)

Results VS Choice of Surgeon

The surgeon you choose for your surgery can have an effect on surgical outcomes and weight loss results, based on technical skill and level of care before and after surgery. It is important to choose a bariatric surgeon that will provide both expertise in the operating room and a multi-disciplinary bariatric program for appropriate patient care.

Average Weight Loss

Most patients reach peak weight loss within 1 to 2 years after surgery. The average rate of weight loss and percentage of excess weight loss (EWL) varies between procedures. It is not uncommon to have slight weight regain after the initial weight loss period.

The following weight loss results are average weight loss results observed in studies; individual measurements vary across a wide range and may be more or less than the average:

  • Gastric Bypass - Works through a combination of restriction and malabsorption; Rapid weight loss in first 6 months, settling at maximum weight loss 18 to 24 months after surgery; 70% EWL at 1 year and 60% EWL at 5 years.
  • Gastric Band - Works by restricting food intake and slowing digestion; Weight loss with laparoscopic adjustable gastric banding is slow and steady (1-2 pounds per week), settling out at maximum weight loss 3 to 4 years after surgery; 55% EWL (range 28-87%) at 5 years.
  • Gastric Sleeve - Works by reducing stomach capacity and reducing hunger cravings; Quick rate of weight loss, reaching 60 to 70% EWL at 2 years.
  • Duodenal Switch - Works primarily through malabsorption with some restriction; Most drastic procedure, used only in cases of super severe obesity; produces lasting 60-80% EWL.

Weight Regain & Revisions

Revisional bariatric surgery is performed to correct or modify a previous bariatric surgery. The top reasons for revisions are: adverse events from original procedure, inadequate weight loss, weight regain, unresolved comorbidities, and nutritional complications.

Results of bariatric surgery revisions can vary widely depending on the original procedure and the reason for the revision.

  • In cases of inadequate weight loss or weight regain, revisional surgery is usually successful if the failure can be attributed to a technical problem of the original procedure, such as a popped staple line, ulcers, or hernia.
  • If the failure is due to behavioral problems, such as unhealthy eating habits, then a revision alone is usually not an effective long-term approach. Success will take a renewed commitment, aided by behavioral therapy and follow-up care.

Obesity is a chronic condition, a long-lasting disease that may be managed with appropriate treatment but never really cured. If the first bariatric procedure does not succeed, a revision offers a second chance of getting your weight and health back to a healthier level.

Achieving a Successful Outcome

One of the primary criteria used to determine whether or not a patient's weight loss surgery reached a successful outcome is percentage of excess weight loss. Generally, from a medical perspective, a successful outcome is one in which the patient is able to achieve a loss of 50% or more of excess body weight and then maintain that level of weight loss over the course of 5 years. Depending on the pre-operative health status of the patient, a successful outcome may also include improvements to obesity comorbidities, especially the resolution or improvement of type 2 diabetes.