Gastric Bypass Surgery and Weight Loss

Gastric Bypass Surgery and Weight Loss

Figure 1: Gastric Bypass Surgery and Weight Loss. 161 teens who underwent Roux-en-Y gastric bypass surgery lost an average of 79 pounds over 5 years. 301 adults who underwent the same surgery lost an average of 88 pounds over 5 years. Teen participants weighed 324 pounds on average before the surgery. Adult participants weighed 326 pounds on average before surgery.

Being obese is not easy. There are many negative physical and psychological consequences that come with it. For the most part, no one chooses to be obese and no one enjoys it.

However, losing weight can be very challenging. Diet and exercise can be notoriously difficult to stick to. Many people never manage to achieve "normal weight" despite a lifetime of efforts.

A new study shows that gastric bypass surgery, while invasive, can be extremely effective for teens and adults.

In a study following 161 teens and 301 adults, teens were on average 79 pounds lighter 5 years after their surgery. Adults were 88 pounds lighter.

What is Gastric Bypass Surgery?

Gastric bypass surgery, also known as Bariatric Surgery, is a type of procedure intended to help people lose weight. There are multiple types of gastric bypass surgery, but generally they all work to reduce the size of the stomach. A smaller stomach gets filled faster, causing patients who receive the surgery to feel "full" with less food. Over time, this can help patients lose a lot of weight, alongside a good diet and exercise regimen.

Evidence Score:


Sample Size - This study used large sample sizes among teens and adults to estimate findings.


Effect Size - This study found a significant and relevant effect sizes for diabetes and high blood pressure


Study Type - This study used an observational study design. These studies are generally less preferred compared to clinical trials given the potential for bias.

Source: Five-Year Outcomes of Gastric Bypass in Adolescents as Compared with Adults

Gastric Bypass Surgery and Diabetes

Gastric Bypass Surgery and Diabetes

Figure 2: Gastric Bypass Surgery and Diabetes. Gastric Bypass is highly effective in “curing” diabetes among teens and adults. Over 80% of teens who had diabetes initially became diabetes free after their surgery. Nearly all remained diabetes free over 4 years.

One key benefit of losing weight the potential "remission" of diabetes. Diabetes is a very common but potentially deadly disease that can cause patients to lose their sight and potentially lose toes as well. Patients in the later stages of diabetes have to inject themselves with insulin to keep their diabetes under control.

This study showed that for teens in particular, gastric bypass can reverse diabetes for the majority of patients. 80% of teen patients who underwent gastric bypass surgery were diabetes free 4 years later.

The Connection between Weight and Type 2 Diabetes

Type 2 Diabetes is caused by high blood sugar. Normally, the pancreas produces insulin to manage blood sugar and move it inside cells. When blood sugar levels are too high, it can overwhelm the body's ability to transport and manage blood sugar, leading to diabetes. The same factors that lead to weight gain also drive diabetes. Likewise, significant weight loss in some cases can cause diabetes to go into remission.

Diabetes "Remission" vs Cure

The term remission is the medically preferred term for the reversal of diabetes, as diabetes always carries the risk of relapse. Even if you test negative for diabetes, and you're off all medication, you would still be in remission despite not meeting any diagnostic criteria for diabetes.

Diabetes + Weight Loss

Gastric Bypass should generally be used only after diet and exercise have failed to control weight. As with any surgery, it is an invasive procedure that carries risks.

Diet alone can be very effective in treating diabetes if done correctly. Nearly half of patients in this one-year study managed to cure their diabetes. Meal replacement shakes and weight loss was all that they needed.

Weight Loss and Diabetes Remission

Gastric Bypass and High Blood Pressure

Gastric Bypass Surgery and High Blood Pressure

Figure 3: Gastric Bypass and High Blood Pressure. Gastric Bypass Surgery was effective in reversing high blood pressure in adults and teens. Over 60% of teens who had high blood pressure were in remission after four years. Similarly, around 40% of adults who had high blood pressure were in remission 4 years later.

Similar to diabetes, high blood pressure is another potentially deadly medical condition driven by the same factors as weight gain. In this study, teens actually benefitted more from gastric bypass surgery than adults when it came to blood pressure. Over 60% of teens were "cured" of their high blood pressure 4 years after their surgery, compared to around 40% of adults.

Roux-en-Y: How It's Done

Roux-en-Y: How It's Done

Figure 4: Roux-en-Y: How It's Done. Roux-en-Y surgery involves attaching the small intestine directly to a small stomach pouch. After this surgery, food bypasses most of the stomach and much of the small intestine. The remaining stomach pouch holds less food and the skipped section of the small intestine absorbs less fat.

This study used a Roux-en-Y procedure on all patients. This type of surgery bypasses most of the stomach and part of the small intestine by attaching part of the small intestine directly to a small section of the stomach.

After this surgery, food bypasses most of the stomach and part of the small intestine. This reduces the amount of food the stomach can hold as well as fat absorption in the bypassed segment of the small intestine.

Key Takeaways

This study adds to a growing body of evidence that shows the effectiveness of gastric bypass surgery.

Diet and exercise are of course the best treatment for obesity. However, we need to acknowledge that these do not work for everyone. Gastric bypass surgery can be a good option for those who have failed to lose weight with diet and exercise.

Gastric Bypass surgery has traditionally only been offered for older adults. This is one of the first studies to show significant benefits for gastric surgery in teenagers.