Bariatric Surgery FAQ

How Much Weight Loss to Expect With a Gastric Bypass

How Much Weight Loss to Expect With a Gastric Bypass - Bariatric Fusion

If you qualify for bariatric surgery, then you’re probably wondering how much weight loss a gastric bypass procedure can provide. Weight loss surgery results can differ.

Gastric Bypass surgery is a tool for weight loss and a successful tool at that. However, it’s important that to understand exactly how much weight loss typically occurs following surgery in order to maintain realistic expectations.

There are various factors that influence how much weight loss gastric bypass procedures result in. We will explore this in more detail below to provide a clear understanding of what weight loss post-surgery will look like.

What This Article Covers:

How Much Weight Can You Lose in the First Month After Gastric Bypass?

While weight loss after gastric bypass surgery differs on an individual basis,

the first few months are typically when significant weight changes are seen. On average, weight loss within the first 30 to 60 days post-surgery is between 5 to 15 pounds per week. This will continue to slow down to about 1 to 2 pounds per week after the first six months.

There are many factors that affect weight loss after gastric bypass surgery. A consistent multivitamin regimen, meal replacement shakes for bariatric patients, dietary change and exercise will assist in maintaining healthy weight loss after surgery while providing the proper nutrients.

Looking at long-term expectations, successful weight loss at about 1 year out from surgery would be more than 40% of excess weight. Overall, average weight loss after gastric bypass surgery can be up to 70% of excess body weight.

Weight loss will differ on an individual basis due to medical conditions, medications, dietary habits, lifestyle change, and environmental factors.

Mini Gastric Bypass Weight Loss

A mini gastric bypass still yields highly effective results in terms of weight loss and carries a lower complication rate. A mini gastric bypass procedure can still produce similar weight loss outcomes compared to a regular gastric bypass procedure. Weight loss will still slow around 6 months after surgery.

The downside to this surgery is that it is usually not covered by most insurance carriers. There are a limited number of surgeons qualified to perform this procedure.

Do You Lose More Weight With a Gastric Bypass or a Gastric Sleeve?

Again, the results after bariatric surgery will differ with each case and patient. In most cases, a gastric bypass will result in patients losing between 50% to 90% of excess body weight 5 years after surgery.

Gastric sleeve patients tend to lose slightly less than this over the same period of time. The excess weight loss percentage is around 40% to 80%.

Regardless of the amount of weight loss, bariatric patients need to always remember the importance of a bariatric specific multivitamin for life after any bariatric procedure. This is essential in preventing common deficiencies and long-term complications.

Is it Possible to Not Lose Weight After Gastric Bypass?

Weight loss will happen in varying amounts after bariatric surgery. Even after the correct surgical approach and the proper follow-up procedures, some patients do not end up losing the desired amount of weight. This is a rare case and only occurs between 5% - 15% of patients.

If you’re concerned about weight loss after bariatric surgery, consult with a registered dietitian on how to restart weight loss after gastric bypass.

How Much Weight Do You Have to Lose Before Weight Loss Surgery?

Pre-surgery weight loss is not always a requirement, but there can be benefits to weight loss before bariatric surgery. Some patients will need to lose weight in order to reach a certain goal before undergoing bariatric surgery. This can help to reduce the risk of complications that could occur during surgery.

In some cases, patients are put on a liver reduction diet in order to reduce the size of the liver. This diet will usually result in some weight loss as well. It is commonly recommended because Non-Alcoholic Fatty Liver Disease (NAFD) is seen in one-third of individuals who are severely obese and can cause complications during surgery. The bariatric guide to the liver reduction diet can provide some insight on this topic.

Make sure you understand the weight requirement for gastric bypass in order to have an idea of what you may need to do before surgery.

Understanding Recovery After Gastric Bypass Surgery

As a result of major surgery combined with rapid weight loss, recovery after gastric bypass surgery needs to be taken seriously. Patients are generally required to remain in the hospital for around 2 to 3 days after surgery. Recovery will require patience and time in order to get back to performing daily activities without requiring assistance.

When the body experiences significant weight loss during the recovery period, it is vital to continue taking bariatric multivitamins in order to keep the body functioning at an optimal level.

Gastric Bypass Revision and Weight Loss

Many people forget that bariatric surgery is only a tool for weight loss. The procedure will only be successful in the long-term if you maintain a healthy lifestyle change, including exercise and dietary habits.

For bariatric patients that do not reach desired weight loss goals, a gastric bypass revision or gastric sleeve revision may be necessary after the initial gastric bypass procedure. However, gastric bypass revision patients must not expect to achieve the same weight loss that was achieved from the initial gastric bypass procedure.

The percentage of weight loss will usually differ based on the revision option that is chosen. It is important to discuss weight loss expectancy and complication rate with your surgeon for any kind of bariatric revision surgery.


Bariatric surgeries are highly effective for weight loss, but amount of weight loss will differ on an individual basis. It is important to have a full understanding of the bariatric procedure you are undergoing in order to prepare for the post-op experience.

Of course, weight loss will fluctuate between each operation and scenario. Be prepared for anything to happen and utilize bariatric resources when needed.

Did you find our blog helpful? Then consider checking:

**This blog is for information and education purposes only. This information is not intended to substitute professional medical advice, diagnosis, or treatment. Please consult with your physician or another qualified health provider with any questions in regards to a medical condition. A qualified healthcare professional can best assist you in deciding whether a dietary supplement is suitable based on your individual needs.

Enjoy our recipe and articles?