Discover Your True Weight Loss Potential with Our Bariatric Surgery Calculator!

Bariatric surgery is a transformative option for individuals struggling with morbid obesity, offering solutions to excess weight, related health issues, and overall quality of life. Procedures like gastric sleeve and gastric bypass can be a crucial turning point for those who have found long-lasting and significant weight loss unattainable through other methods. A common question among those considering bariatric surgery is, "How much weight will I lose?" This article explores the factors influencing weight loss after bariatric surgery and introduces the concept of a bariatric surgery weight loss calculator as a tool for setting realistic expectations.

Bariatric Surgery: A Path to Improved Health

Metabolic/bariatric surgery (MBS) is currently the most effective measure to treat morbid obesity and obesity-related comorbidities. It has proven effective not only in terms of short-term weight loss, but also in maintaining the lower body weight for several decades, improving patient quality of life and extending life expectancy.

The prevalence of obesity, defined as a body mass index (BMI) higher than 30 kg/m2, has gradually increased around the globe. Obesity and its related diseases are expected to reduce life expectancy. For these reasons, the Korean National Health Insurance plan began to cover MBS. Patients with a BMI above 35 kg/m2 or a BMI above 30 kg/m2 with obesity-related comorbidities now qualify for insurance coverage for MBS.

MBS is now undisputedly the most effective measure to treat morbid obesity and obesity-related comorbidities. Many clinical trials have shown that surgical treatment achieves significantly better weight loss outcomes than medical treatment, as well as better resolution or improvement of obesity-related comorbidities, such as type 2 diabetes, dyslipidemia, and hypertension.

Factors Influencing Weight Loss After Bariatric Surgery

Weight loss after metabolic/bariatric surgery is influenced by many clinical variables, including initial body mass index, age, gender, ethnicity, and type of surgery.

Read also: Diet Before Bariatric Surgery

Type of Surgery: Different bariatric procedures lead to varying degrees of weight loss.
Commitment to Lifestyle Changes: Sustained weight loss depends on adopting new habits related to diet, activity, and behavior.
Individual Factors: Surgeons' technique, age, genetics, gender, starting weight, diabetes, and hypertension also determine the amount of weight reduction.

Weight Loss Reporting Systems

To understand the literature reporting weight loss after MBS, it is necessary to understand the weight loss reporting systems commonly used. The percentage of excess weight loss (%EWL) is calculated from the excess weight beyond the ideal body weight. Traditionally, many surgeons have reported weight loss outcomes as %EWL or %EBMIL and change in BMI. When the dynamic percentile charts of nadir BMI, %EWL, and %TWL are plotted against initial BMI using bariatric weight loss outcomes, the absolute BMI values and %EWL results are significantly influenced by initial BMI, unlike %TWL.

Weight loss outcomes show wide variability across patients, even using the %TWL metric, which is the least likely to be influenced by baseline BMI. It is important to understand what causes the weight-loss differences among bariatric patients so that individual patients can be given realistic weight loss goals.

Preoperative Factors

Preoperative BMI can greatly influence weight loss outcomes. Previous studies have demonstrated a clear correlation between initial BMI before surgery and final BMI after surgery.

Age at surgery also affects weight loss outcomes. Still et al. retrospectively reviewed 109 RYGB and 228 SG patients and divided them into two age groups, those younger than 45 years and those older than 45 years. They compared the 1-year weight loss outcomes between those age groups and demonstrated that patient age was negatively associated with weight loss, with the older group showing a significantly higher incidence of insufficient weight loss (14.9% vs. 2.6%), defined as %EWL <50%.

Gender is another clinical factor that might affect weight loss outcomes. Many have reported that being a woman was a favorable factor for greater weight loss. The effects of ethnicity on postoperative weight loss have been the subject of constant discussion. Differences in weight loss outcomes after MBS occur even among Asian ethnicities.

Read also: Bariatric Surgery Outcomes

Many studies have shown that type 2 diabetes is a prognostic factor for poor weight loss after MBS. Mental health conditions, particularly those related to eating behaviors, could be another preoperative predictor of weight loss after MBS.

Surgical Technique

The type of surgery also plays a crucial role in weight loss outcomes. According to two representative randomized controlled trials, SG and RYGB produced comparable weight loss in the early postoperative period. However, the difference tended to increase over time, favoring RYGB in terms of sustained weight loss.

Understanding the Bariatric Surgery Weight Loss Calculator

A bariatric surgery weight loss calculator is a tool designed to estimate potential weight loss outcomes after different bariatric procedures. It takes into account factors like:

Gender: The calculator uses gender to predict weight loss outcomes.
Height: The calculator uses height to predict weight loss outcomes.
Current Weight: The calculator uses your current weight to predict weight loss outcomes.
Type of Procedure: The calculator uses the type of procedure you wish to undergo to predict weight loss outcomes.

By inputting these variables, the calculator provides an estimate of:

Estimated Weight Loss: How much weight a patient should expect to lose after their procedure.
Procedure Comparison: Which procedure will likely lead to the most amount of weight loss.
Motivation: Seeing the possibilities for their weight loss may make patients more likely to embark on the journey.

Important Considerations:

Estimates Only: Calculator results are only estimates and not guarantees.
Individual Variation: Actual weight loss can vary significantly based on individual factors and adherence to post-operative guidelines.
Professional Guidance: Calculators should not replace consultations with a doctor or healthcare provider.

Types of Bariatric Surgery and Expected Weight Loss

There are three common types of bariatric surgery: gastric bypass, sleeve gastrectomy, and the gastric band. Choosing the most suitable type of bariatric surgery depends on factors such as the patient’s overall health, body mass index (BMI), and individual preferences.

Gastric Bypass (Roux-en-Y)

In gastric bypass, also known as a Roux-en-Y, a small pouch is created at the top of the stomach, limiting the amount of food it can hold. The small intestine is then rearranged to connect to this pouch, reducing the absorption of calories and nutrients. This surgery both restricts food intake and alters the digestion process, leading to significant weight loss.

Weight Loss Expectations: In less than a year, gastric bypass patients can lose 60 to 80% of their excess weight on average. After 3 to 5 years, RNY patients have reported 30% of their total body weight reduced. At 10 years, patients maintain a consistent loss of 28.6% of their total body weight.

Sleeve Gastrectomy (Vertical Sleeve Gastrectomy)

Sleeve gastrectomy involves the removal of a large portion of the stomach, leaving a smaller, banana-shaped "sleeve." This reduces the stomach's capacity and limits the production of the hunger hormone ghrelin. The surgery primarily restricts the amount of food that can be consumed and reduces feelings of hunger, contributing to weight loss.

Weight Loss Expectations: 12 months after gastric sleeve, patients can shed 23.4% of their baseline weight or 63% of their excess weight. 3 years patients can expect to lose at least 50% of their excess weight. More than 4 years after their surgery, patients normally lose 17.8% of their total body weight or 43.0% of their excess weight.

Duodenal Switch (Biliopancreatic Diversion with Duodenal Switch)

A duodenal switch, also known as a biliopancreatic diversion with duodenal switch (BPD-DS), is a complex type of bariatric surgery designed for patients who need aggressive weight loss and have exceptionally high BMIs of over 45. While the average weight loss timeline after the duodenal switch has stronger and faster results, it is important to follow strict vitamin and diet guides to avoid not losing enough weight. Within the first year, 84% of DS patients lose at least 50% of their excess body weight and up to 80%+. Over 2 years, patients usually lose 60% to 80% of their excess body weight. 84.2% of these patients maintain this weight loss 3 years after the surgery.

Adjustable Gastric Band (LAP-BAND)

The Gastric Band, or Lap-Band, is an adjustable silicone ring that creates a small pouch at the top of the stomach. This temporarily blocks food, slowing down the digestive process and making the patient feel full faster. Based on the patient, the pouch is tightened or loosened for maximum weight loss success.

Weight Loss Expectations: While it moderately restricts the patient’s food consumption, the lap-band weight loss results are almost half as effective as other procedures. After the 1st year, gastric band patients are expected to lose 20% to 60% of excess body weight. By the 5th year after the surgery, 46% of excess weight loss. 10 years after surgery, patients maintain 65% of excess weight loss.

Gastric Balloon

If a bariatric patient wants to avoid an invasive procedure or needs to lose weight extensively before another surgery, they can opt for a non-surgical Intragastric Balloon. The gastric balloon weight loss system is inserted through the esophagus into the stomach, making it uncomfortable to overeat. Based on the gastric balloon system, such as Spatz and Orbera, it is then deflated and removed endoscopically after 6 to 12 months.

Weight Loss Expectations: While the balloon can have positive side effects, it sheds fewer pounds compared to nearly all other procedures and unfortunately, patients can easily go back to bad habits afterward. Within 6 months, 30-47% excess weight loss is expected with Orbera when it is removed. By 6 months with Spatz, 26.4% excess weight loss. After 12 months, 48.8% excess weight loss with Spatz when it is removed.

Lifestyle Changes: The Key to Long-Term Success

With bariatric surgery, lifestyle changes have to be made for effective and long-lasting weight loss success. The most significant adjustments for bariatric patients are the new dietary and medical arrangements.

Dietary Adjustments and Portion Control: Bariatric surgery often involves reducing the size of the stomach or altering the digestive tract, which can impact nutrient absorption. Following a prescribed diet ensures that patients receive the necessary nutrients in appropriate amounts to prevent deficiencies and support overall health. Portion control is crucial to avoid overeating, maximize nutrient absorption, and facilitate weight loss. Certain foods, particularly those high in calories and low in nutritional value, can impede weight loss progress.
Regular Physical Activity: Regular physical activity contributes to weight loss and overall well-being. It does this by helping burn calories, contributing to a negative energy balance that promotes weight loss. Exercise can boost the metabolic rate, even during periods of rest. This increase in metabolic activity supports ongoing calorie expenditure, making it easier for individuals to maintain weight loss over time.
Stress Management and Sleep Prioritization: Combining stress management and prioritizing sleep with dietary changes and regular exercise creates a holistic and sustainable approach to weight loss after bariatric surgery. Stress often leads to emotional eating, where individuals use food as a coping mechanism. Adopting stress management techniques such as mindfulness, deep breathing, meditation, or yoga can help patients develop healthier coping mechanisms. These practices enhance self-awareness and empower individuals to make mindful food choices. Additionally, inadequate sleep disrupts hormonal balance, leading to an increase in ghrelin (hunger hormone) and a decrease in leptin (satiety hormone). This hormonal imbalance can result in heightened cravings and overeating.
Building a Support System: Bariatric surgery is a life-changing experience that can bring about various emotions, including excitement, anxiety, and sometimes even stress. Having a support system, comprising friends, family, or support groups, provides emotional reassurance during the post-surgery period. Knowing that others are aware of the weight loss goals creates a sense of accountability.
Nutritional Supplementation: The procedures involved, such as gastric bypass or sleeve gastrectomy, often lead to reduced food intake and altered nutrient absorption. As a result, patients may face challenges in meeting their nutritional needs through regular dietary intake alone. Protein is a critical component for maintaining muscle mass and promoting healing after surgery. Supplemental protein shakes or powders may be recommended to help patients achieve their protein goals. Bariatric surgery can lead to deficiencies in vitamins and minerals, such as vitamin B12, iron, calcium, and vitamin D.

Beyond the Numbers: Non-Scale Victories

Bariatric surgery is not a cosmetic procedure. You will lose weight and may look better. But the success of bariatric surgery should be based on a reduction of co-morbidities, improved longevity, and an improved quality of life, not numbers on a scale. Are you happier, healthier, and going to live longer?

Let’s take a look at some non-scale victories:

When you don’t need the extender belt on an airplane.
When you can shave your legs without a struggle or mirror.
When you make it up the stairs without breaking a sweat.
When you are not embarrassed to take a picture.
When you get to wear that dress that you’ve had in your closet for years.
When you can cross your legs.
When you aren’t the biggest person in the room.
When you fit comfortably in a seat.
When you can wrap a standard bath towel around your body.
When you don’t have to shop at plus size stores.
When you can get in and out of booths easily at restaurants.
When your joints don’t hurt at the end of the day.
When you are not the ‘fat’ member of your group of friends.

The list can go on and will be different for everyone. Losing weight does so much more than just improving medical conditions and lowering the number on your scale. But you have to stay focused, and you have to change. Celebrate your non-scale victories. Make a list of the things you want to do that your weight has prevented you from doing and reward yourself when you reach those goals. Don’t reward yourself with food.

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