Bariatric diet: What to eat and drink before and after weight loss surgery

Key Points

• Your diet matters for the success of bariatric surgery and shapes long-term results.
• Before surgery, your doctor may switch you to a high-protein, low-carb diet to shrink your liver and prepare your body for the procedure.
• After surgery, your diet transitions through careful stages over 8-12 weeks. It starts with clear liquids, then pureed foods, soft foods, and finally regular foods.
• Working with a bariatric dietitian can help prevent nutritional gaps and build lasting healthy eating habits that work for you.

If you’re considering weight loss surgery, your diet plays a significant role in how well you recover. However, getting used to a new way of eating can feel overwhelming. 

You may be wondering what foods are safe to eat or when you can enjoy your favorite meals again. You're not alone. Many people have successfully adopted a bariatric diet with the right support.

Let's explore what to eat before and after bariatric surgery, step by step. These guidelines apply to all bariatric surgeries, including gastric bypass and gastric sleeve (sleeve gastrectomy).

What to eat before weight loss surgery

Before your gastric bypass or gastric sleeve surgery, you'll follow a special diet that can help make your surgery safer and more likely to succeed. This pre-surgery diet serves two important purposes:

• It helps shrink your liver, which makes the surgery safer and easier to perform
• It helps you start learning new eating habits that you'll continue after surgery

“Your doctor might ask you to start this diet as soon as you're approved for surgery. Following it carefully is important—if you don't lose enough weight beforehand, your surgery might need to be rescheduled,” notes Suzanna Thoe, RD, Registered Dietitian.

Your pre-surgery eating plan

Here's what to eat and drink in the weeks before surgery:

• Focus on high-protein, low-carb foods
• Avoid foods with lots of fat, like whole milk products and fried foods
• Skip sugary drinks, including fruit juice
• Choose sugar-free foods and drinks
• Take a daily multivitamin
• Drink at least 64 ounces of water each day
• Avoid drinking with meals

In the two weeks right before surgery, your doctor might switch you to mostly liquids. This might include protein shakes and other easy-to-digest foods.

What to eat and drink after weight loss surgery

After weight loss surgery, your body will need time to heal. This is true even after minimally invasive surgery like laparoscopic surgery. 

This is why there are stages to a bariatric diet. Each one is designed to help you get better and make sure you get the nutrients you need.

Plus, your stomach can now hold less food, and your appetite decreases. While this is the sign of a successful bariatric surgery, every bite you eat needs to count towards good nutrition before you get full. A well-planned gastric bypass diet or gastric sleeve diet can help you achieve this goal.

Let’s look at a typical diet after bariatric surgery.

Stage 1: Liquids only (weeks 1-2)

For the first two weeks after gastric bypass surgery or gastric sleeve surgery, your stomach is most tender and needs gentle nutrition.

Here's what to eat and drink during this stage:

• Clear broths: Give you fluids and minerals while being easy on your stomach
• Sugar-free gelatin: It’s a sweet treat but without sugar which might upset your stomach
• Drinks without caffeine or sugar: Keep you hydrated without irritating your stomach

Later in this stage, you may graduate to:

• Decaffeinated coffee or tea without sugar
• Strained cream soups

“It’s best to go slow and learn how your new stomach is responding to your food and drink intake. Take small sips and stop if anything feels uncomfortable,” says Thoe, RD.

Stage 2: Smooth, pureed foods (weeks 3-4)

As you progress with your weight loss goals, you can move on to blended foods that have a smooth, pudding-like texture. Your food choices may grow to include:

• Meats and fish blended until smooth: Give you the protein you need for healing
• Cooked vegetables blended well: Provide vitamins and dietary fiber that are easy to digest
• Yogurt without added sugar: You get protein and good bacteria for digestion
• Smooth, strained soups: Help with both nutrition and staying hydrated

Remember, during this stage, everything should be as smooth as pudding—if you feel any lumps, blend it more. This helps protect your healing stomach.

Stage 3: The soft foods phase (weeks 5-8)

This stage marks an exciting transition toward regular eating patterns. Foods should be tender and easily chewable to prevent any strain on your stomach. Your menu now includes:

• Well-cooked, soft vegetables: Provide essential vitamins and minerals in an easier-to-digest form
• Tender, ground lean meats: Offer necessary protein while being gentle on your stomach
• Soft-boiled eggs: Rich in protein and nutrients, easy to digest
• Soft, fresh fruits without seeds or skins: Add natural sweetness and nutrients while being gentle on your system

Take time to chew each bite thoroughly and have smaller portions to prevent discomfort.

Stage 4: Returning to regular foods (after week 8)

About two months after surgery, you can start adding regular foods back into your diet. This is a gradual process, and you will still need to:

• Cut food into small, bite-sized pieces
• Chew thoroughly
• Stop eating when you feel satisfied
• Pay attention to portion sizes (about 1 to 1½ cups of food per meal)

Some foods might still be hard to digest at this stage. Take your time trying:

• Regular meats (not ground)
• Raw vegetables
• Fresh fruits with skins
• Breads and grains

Add one new food at a time and notice how your body responds. If something causes discomfort, wait a few weeks before trying it again. Remember to:

• Focus on lean proteins, vegetables, and fruits
• Keep portions small
• Avoid foods high in fat and sugar
• Continue drinking water between meals, not with meals

“Most people can eat regular food by 4 months after weight loss surgery, though in much smaller portions than before. Your dietitian can help you figure out the right portions and food choices for your weight loss goals,” explains Thoe, RD.

Important tips for your daily routine

Adapting to your new eating pattern takes time and attention. Here's how to make it work for you:

• Take small bites and chew thoroughly: This prevents discomfort and helps you appreciate each bite
• Eat slowly (20-30 minutes per meal): This gives your body time to signal fullness
• Stop eating when you feel satisfied: Learn your body's new fullness signals
• Stay hydrated between meals: Drink water 30 minutes before or after eating, not during your meal
• Focus on protein-rich foods first: This way, you get this essential nutrient before your stomach fills up

Managing common challenges

Dealing with dumping syndrome

Dumping syndrome happens when food moves too quickly from your stomach to your small intestine. You might experience:

• Nausea or vomiting
• Dizziness
• Racing heartbeat
• Sweating
• Weakness or fatigue

To help prevent dumping syndrome:

• Avoid foods high in sugar and fat: These can overwhelm your digestive system
• Eat slowly and chew thoroughly: This helps control how quickly food enters your system
• Wait 30 minutes after meals before drinking: Prevents overloading your stomach
• Keep portions small and consistent: Helps your body adapt to its new capacity

Thoe, RD says, “If you experience the symptoms of dumping syndrome, reach out to your healthcare provider right away. They can help you manage these symptoms effectively. Working with a bariatric nutritionist dietitian can also help you identify and avoid trigger foods.”

Getting enough nutrition with a smaller stomach

Your smaller stomach capacity presents unique nutritional challenges. After surgery, your body absorbs fewer nutrients from food, and you eat smaller portions.

Healthcare professionals typically recommend eating several small meals throughout the day—starting with six small meals, then moving to four meals, and finally adjusting to three properly portioned meals daily. Each meal should consist of about 1/2 to 1 cup of food to ensure proper nutrition without overwhelming your new stomach capacity.

To ensure proper nutrition:

• Prioritize protein (60-100 grams daily): Supports healing and maintains muscle mass
• Stay hydrated with 64 ounces (1.9 liters) of fluids per day: Essential for preventing dehydration
• Take recommended supplements: Your healthcare provider may prescribe vitamin B12, calcium, iron, and a multivitamin to prevent deficiencies
• Choose nutrient-dense foods: Makes every bite count nutritionally
• Work with your healthcare team: Regular monitoring helps catch and prevent deficiencies

Frequently Asked Questions (FAQs) about bariatric diets

When can I eat regular foods again?

You can usually start eating regular foods about 8-12 weeks after gastric sleeve or gastric bypass surgery but in smaller portions. The key is listening to your body and introducing foods gradually. However, remember that each person’s recovery may look different.

How can I prevent nutritional deficiencies?

After weight loss surgery, your body doesn't absorb nutrients the same way it used to because your stomach is smaller. Here's how to stay healthy.

Regular check-ups are key

• Schedule follow-up visits as recommended by your healthcare team
• Get your vitamin and mineral levels checked regularly
• Don't skip appointments, even if you're feeling good

Take your supplements every day

• Your doctor may recommend vitamin B12, iron, calcium, and a multivitamin
• Set reminders to take them at the same time each day
• Keep track of which supplements you take and when
• Let your healthcare team know if you have trouble taking any supplements

Work with a bariatric dietitian

• Knows your specific nutritional needs after weight loss surgery
• Can create custom meal plans that work for your lifestyle
• Helps you meet your protein goals (60-100 grams daily)
• Shows you how to plan and prepare meals
• Can answer questions about specific foods or supplements
• Helps you adjust your diet as your needs change

What if I'm struggling with the diet plan?

It can be hard to focus on recovery after surgery, getting back to your daily routine, and planning your meals based on your unique needs. A bariatric dietitian covered by your insurance can help you through this transition with a personalized diet plan and strategies that work for your life.

Looking ahead

Your bariatric diet is a tool that helps you adapt to and thrive with your body's changes. While the journey may seem complex, remember that support is available. Whether you're just starting or well into your journey, a registered dietitian specializing in bariatric nutrition can provide personalized guidance and support.

Find the right bariatric dietitian, covered by insurance, to help you start your weight loss journey.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.