Bariatric surgeries are considered to be the most effective treatment for obesity today. Individuals undergoing such surgeries can expect significant weight loss, up to 50-70% of their excess weight in the first 2 years after the procedure.

It is not possible to predict exactly how much each individual will lose, as factors such as the type of surgery, preoperative weight, overall health, and adherence to lifestyle change recommendations play a crucial role.

Gastric bypass surgery usually leads to more weight loss than sleeve gastrectomy in the long term. Research has shown that patients undergoing gastric bypass can expect to lose about 60-70% of their excess weight. On the other hand, those opting for sleeve gastrectomy may hope to lose around 50-60% of their excess weight.

The first year after the surgery is when weight loss is most pronounced. For those undergoing sleeve gastrectomy, most reach their lowest body weight around 12 -18 months after the procedure. For those undergoing gastric bypass, weight loss tends to slow down or stabilize after 18-24 months. It is crucial to note that there is a significant variation among individuals, and the figures mentioned above are based on averages. Predicting how much each person will lose after surgery remains uncertain.

It’s important to remember that weight loss itself is not always the primary goal of these surgeries, as health improvements can be multifaceted. For instance, conditions like high blood pressure may improve, and some individuals may even discontinue blood pressure medications. Individuals with diabetes may reduce or stop diabetes medications. Sleep apnea can improve, and generally, most people experience better sleep quality. Losing weight reduces strain on joints, making physical activity easier, and decreases musculoskeletal pain.

Metabolic surgery is not a cure for obesity; it helps you get back to a new starting point. Everyone needs to work on lifestyle changes after surgery, improve their diet, increase physical activity, manage stress, and ensure adequate sleep.

Usually, the Body Mass Index (BMI) is used to determine ideal weight and excess weight. Here you can calculate your BMI and get your ideal weight.


Person 1. Is 135 kg and height 175cm, calculated BMI is 44,08, and ideal weight would be 77kg. The person has about 58 kg in overweight (135-77).

50% weight loss would result in loss of 29 kg, and weighing 106 kg.

70% weight loss would result in loss of 40,6kg, and weighing 94,4kg.

Person 2 . Is 98kg and height 162cm, calculated BMI is 37,34, and ideal weight would be 66kg. The person has about 32 kg in overweight (98-66).

50% weight loss would result in loss of 16 kg, and weighing 82 kg.

70% weight loss would result in loss of 22,4kg, and weighing 75,6kg.


O’Brien, P.E., Hindle, A., Brennan, L. et al. Long-Term Outcomes After Bariatric Surgery: a Systematic Review and Meta-analysis of Weight Loss at 10 or More Years for All Bariatric Procedures and a Single-Centre Review of 20-Year Outcomes After Adjustable Gastric Banding. OBES SURG 29, 3–14 (2019).

Golzarand, M., Toolabi, K. & Farid, R. The bariatric surgery and weight losing: a meta-analysis in the long- and very long-term effects of laparoscopic adjustable gastric banding, laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy on weight loss in adults. Surg Endosc 31, 4331–4345 (2017).


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