In 2022, nearly 280,000 bariatric surgeries were performed in the United States. Gastric bypass surgery is a life-changing procedure designed for significant, long-term weight loss. After undergoing a gastric bypass surgery, you may find yourself wondering if it’s possible to gain weight again. The short answer is yes, although there are several strategies for managing weight after surgery.

For many, bariatric surgery offers hope for treating obesity and its impact on physical health, mental well-being, and life expectancy. One member of MyObesityTeam wrote, “I have gained about 80 pounds (and maybe a little more) more than once. … It has been a constant struggle. The surgery is merely a tool to help us lose it and keep it off. We still have to be aware of calories and nutrition every day.”

Understanding why and how weight gain happens can help people maintain their weight loss and improve their overall well-being, so read on to learn more.

How Gastric Bypass Changes Your Body

There are a few types of weight loss surgeries, or bariatric surgeries. The most common types are gastric sleeve (sleeve gastrectomy) and Roux-en-Y gastric bypass (RYGB). Keep in mind that a gastric sleeve surgery is permanent, while a Roux-en-Y gastric bypass is reversible. Both surgeries will require lifelong vitamin supplementation, including fat-soluble vitamins, as well as iron in some cases.

People lose an average of 70 percent of their excess weight within the first two years after gastric bypass surgery. The average long-term weight loss is 50 percent of excess weight, maintained through healthy habits and regular follow-ups.

Gastric sleeve surgery is the most common type of bariatric surgery, and it involves removing about 80 percent of the stomach. Food will continue to travel through the stomach to the intestines after surgery.

During a Roux-en-Y gastric bypass surgery, doctors staple the stomach to create a small stomach pouch about the size of an egg and connect it directly to the small intestine, forming a “Y” shape. The procedure is a laparoscopic surgery, which means it’s minimally invasive and only has small incisions.

The Roux-en-Y changes how your body and digestive system handle food in two main ways:

• The smaller stomach pouch means you feel full after eating less food, reducing overall food intake.
• Food bypasses part of the small intestine, reducing calorie and nutrient absorption.

According to Cleveland Clinic, people lose an average of 70 percent of their excess weight in the first year or two following gastric bypass surgery. While weight changes over time after surgery, the average long-term weight loss is 50 percent of excess weight, especially with consistent follow-up, healthy eating habits, and regular physical activity.

Why Weight Gain Happens

In a 2024 meta-analysis study, researchers found that 49 percent of people regained weight after gastric bypass surgery, and 42 percent of people regained weight following a Roux-en-Y gastric bypass. There are a few factors that can contribute to weight regain.

Stretched Stomach Pouch

The stomach pouch can stretch over time if individuals regularly eat large portions. One study found that gastric pouch enlargement, or stretching, occurred in about 28 percent of people who regained weight after a gastric bypass procedure. This stretching allows individuals to eat more food before feeling full, essentially “retraining” their stomachs to consume more calories.

A 2024 study found that 49 percent of people regained weight after gastric bypass surgery, with 42 percent regaining weight specifically after Roux-en-Y gastric bypass.

A MyObesityTeam member shared, “I had Roux-en-Y bypass surgery in September 2010. By January of 2011, I had lost 100 pounds. I gained back 30 pounds and have lost 10 again. I definitely should have lost more weight, but I think I may have stretched my pouch again.”

Changes in Eating Habits

Common habits that lead to weight gain after surgery can include:

• Consuming high-calorie foods and sugary drinks
• Frequent snacking between meals or grazing throughout the day instead of eating structured meals
• Eating larger portions than recommended or binge eating
• Consuming liquid calories through sodas, alcohol, or sweetened beverages

Hormonal Changes

Your body naturally tries to regain lost weight by adjusting your hormone levels, such as ghrelin, which is known as the “hunger hormone.” A study found that some of these hormonal changes can be noticed shortly after surgery, while others are more long term and occur over the course of a year. These changes to hormones can actually lead to an increase in appetite and food cravings, causing you to consume more.

Preventing Weight Regain After Bariatric Surgery

Keep in mind that everyone’s body is different, so what works for one person might not work for another. Work with your healthcare team to figure out the best approach for you after bariatric surgery.

Generally, the following strategies can be used to help minimize weight regain or complications after surgery.

1. Follow Your Diet Plan

After surgery, you’ll have to follow a specific diet and monitor your food intake for a set period of time while your body heals. This usually consists of a liquid diet followed by blended or softer foods for the first six to eight weeks after your operation.

Once you get your doctor or dietitian’s OK, try to:

• Eat protein-rich foods before other foods at every meal.
• Choose whole foods over processed foods.
• Avoid liquid calories from sodas, alcohol, and sweetened drinks.
• Opt for smaller, more frequent meals throughout the day rather than a couple of larger meals.
• Stop eating when you begin to feel full, even if food remains on your plate.
• Use small plates and measure portions when needed.
• Completely chew your food to prevent blockages in your intestine.
• Drink enough water, around 8 cups a day.

Following a structured post-surgery diet — prioritizing protein-rich, nutrient-dense foods and avoiding liquid calories — is essential for minimizing weight regain and maintaining long-term results.

Incorporating recipes for obesity management into your diet plan can also help ensure you meet nutritional needs while maintaining variety and satisfaction.

2. Stay Active

Exercising has a number of benefits, such as minimizing feelings of hunger and reducing stress levels. Try to get in 150 minutes of exercise per week, including a mix of cardio and strength training.

As you increase your physical activity levels, there are a number of exercise options you can incorporate:

• Daily walks or light jogs
• Yoga or stretching for flexibility
• Low-impact workouts, like Pilates, swimming, or water aerobics
• Cycling
• Strength training with guidance

You’ll be much more likely to complete workouts if they fit into your current schedule instead of planning your whole day around them. If you miss a workout, don’t be hard on yourself, and try your best to get back on track the next day.

3. Attend Regular Checkups

See your healthcare team regularly to monitor your nutritional status and vitamin levels. Your doctor can also identify and address potential issues, such as weight regain after bariatric surgery, stomach pouch changes, or complications like a fistula or dilation.

If you notice weight regain after surgery, your doctor may recommend medications using glucagon-like peptide 1 (GLP-1) receptor agonists, like semaglutide (Wegovy) or tirzepatide (sold under the brands Mounjaro and Zepbound). These medications can be used before or after bariatric surgery to prevent weight gain or to increase weight loss.

4. Join Support Groups

Many people have found success through peer support groups. Support groups can be beneficial for building resilience, providing emotional support during challenges, and offering accountability and motivation. Group members may also share practical tips, recipes, and meal-planning ideas you can adopt.

When To Contact Your Doctor

Remember, your healthcare team is here to help you achieve your goals. Don’t hesitate to consult your doctor right away if you notice:

• You aren’t losing weight anymore or are gaining significant weight back.
• You feel nauseated, or you vomit after meals.
• You’re unusually sweaty or dizzy.
• You frequently have diarrhea.
• You’re experiencing new digestive issues.
• You have overwhelming food cravings.
• You’re struggling with emotional eating or binging.

Keep in mind that it’s not uncommon to gain weight after gastric bypass, and it’s manageable with the right approach. Work closely with your healthcare team to address any challenges early, so you can maintain your weight loss in the long term.

Remember that gastric bypass is a tool, not a cure. Sustainable weight loss requires ongoing commitment to lifestyle changes and regular medical follow-ups.

Talk With Others Who Understand

MyObesityTeam is the social network for people with obesity and their loved ones. On MyObesityTeam, more than 56,000 members come together to ask questions, give advice, and share their stories with others who understand life with obesity.

Have you had gastric bypass surgery? Did you notice any weight gain following the procedure? Share your experience in the comments below, or start a conversation by posting on your Activities page.