Gastric Bypass vs Gastric sleeve: What are the Similarities and Differences?

Although most people immediately think of gastric bypass when they hear bariatric weight loss surgery, there are in fact many options for those considering bariatric surgery: gastric bypass, gastric sleeve, gastric band, etc. Each one of these surgeries has its own properties, its own way to induce weight loss, and its own advantages and disadvantages. 

Two surgeries that often get compared are gastric bypass and gastric sleeve, with many patients not being clear on their differences, relative performance, potential complications, etc. Here, we’ll explain both operations and then compare and contrast them, so you, as a patient, can make a more informed decision.

What’s Gastric Bypass and How Does It Work?

Gastric bypass, as its name suggests, is an operation where a small poach is created at the top of your stomach and connected to your small intestine. The food enters that small poach first and then moves directly to your small intestine ‘bypassing’ the rest of your stomach.

This has a few side effects: it makes you feel ‘full’ quicker than you did before. It makes you extract less energy (calories) from the food you eat, and subsequently, because weight loss is all about calories in, calories out, it makes you lose weight.

Gastric bypass is not an operation for everyone who is overweight: to qualify, you have to either be severely obese (a body mass index (BMI) of over 40) or obese (BMI>35) with major obesity-related health problems. Gastric bypass helps with heart disease, type-2 diabetes, high cholesterol, high blood pressure, etc.

What’s Gastric Sleeve and How Does It Work?

Gastric sleeve surgery, also known as sleeve gastrectomy or vertical sleeve gastrectomy, is a common weight loss surgery that involves vertically slicing the stomach and removing around 75% to 80% of it so it is much smaller.

Gastric sleeve patients’ much smaller stomach directly impacts their eating habits: the patient will feel fuller quicker, and this makes them eat less throughout the day inducing weight loss over time. Gastric sleeve is also used to treat many diseases related to obesity: sleep apnea, fatty liver disease, type 2 diabetes, hyperlipidemia, etc.

How Does Gastric Bypass Surgery Compare to Gastric Sleeve Surgery?

Now that we’ve laid down how each operation is carried out, we have covered the necessary ground to start comparing them and delve into their many similarities and many differences.

Similarity Between Gastric Bypass and Gastric Sleeve

Both bariatric surgeries are similar:

• Target demographic

Both surgeries are broadly suitable for the same kind of patients: obese people with a BMI over 35 that suffer from weight-related health complications. Although gastric bypass is generally prescribed to people with a BMI of over 45 (due to its better weight loss effects) if you’re suitable for one of the operations, it is likely you’re suitable for the other.

• Results of the operation

Although there are some key differences, the results of the operation and the recovery broadly follow the same pattern for both procedures: you’ll start losing weight progressively for a 12-18 month period after both procedures, you’ll have to follow a strict diet for months after surgery, and you’ll be facing fairly similar risk profiles during either surgery.

Difference Between Gastric Bypass and Gastric Sleeve

• How each procedure is carried out

How a gastric bypass procedure is carried out, how you need to prepare, and how much you need to spend in the operation room are all different from a gastric sleeve procedure.

• How your body handles food

Although the end effect of both procedures are broadly similar, the way your body handles food after each procedure and how weight loss is induced are starkly different.

In the case of gastric bypass surgery, the operation helps you lose weight through two primary mechanisms: firstly, the smaller poach makes you feel full quicker, which forces you to eat less food, and secondly, due to the fact the food ‘bypasses’ most of your stomach and some of your intestine, your body is mechanically unable to extract as much nutrition from the food as it did before: this means you consume fewer calories for the same amount of food you eat.

In the case of gastric sleeve surgery, the primary weight loss mechanism is the far smaller stomach the patient has after the surgery. Similar to gastric bypass, this makes the patient eat less food and progressively lose excess weight. Unlike gastric bypass, however, a gastric sleeve doesn’t substantially influence how many calories the patient’s body consumes from food.

Gastric Bypass vs Gastric Sleeve: What are the Advantages of Each Operation?

The Advantages of Gastric Bypass over Gastric Sleeve

• The gastric bypass procedure is a more established bariatric surgery than the gastric sleeve. This doesn’t mean gastric sleeve is unsafe or experimental. It just means that there are more studies into the effects of gastric bypass, and there are more surgeons with experience carrying it out.
• As we’ve mentioned before, gastric bypass surgery impacts how your body extracts nutrition from food. This not only makes gastric bypass surgeries more potent weight loss procedures, but it means they can alleviate metabolic syndrome conditions.
• If you suffer from gastroesophageal reflux disease (GERD), gastric bypass surgery is the better option, since gastric sleeve risks exasperating the disease’s symptoms.

The Advantages of Gastric Sleeve over Gastric Bypass

• Gastric sleeve surgery is associated with less hunger, contrary to what people commonly believe. Hunger isn’t just about the mechanical elements of having your stomach feel full or empty, it is also about hormones (released primarily by your stomach) that send signals to your brain that you’re indeed hungry. So, despite gastric bypass patients having a smaller poach for food, since most of their stomach is still intact, the patients’ ability to release hunger hormones remain. While in the gastric sleeve’s case, because around 80% of the stomach is removed, less of the hormone is released. Feeling less hunger is not always an advantage, but for people who want to consistently lose excess weight, it definitely is.
• The weight loss after a gastric sleeve procedure happens more gradually than gastric bypass, and although this might sound like a disadvantage at first, studies are reporting some psychological and physiological benefits of a slower weight loss process (from less soggy skin to higher muscle retention).