Gastric Bypass Diet

Role of Diet in Gastric Bypass

Before undergoing gastric bypass surgery, you must first qualify for the surgery and understand the risks and benefits involved.

Adults eligible for this surgery are typically more than 100 pounds overweight or have a body mass index (BMI) over 35.

You may also be eligible if your BMI is between 30 and 35, your health is at risk due to your weight, and making lifestyle changes hasn’t led to weight loss, according to the American Society for Metabolic and Bariatric Surgery (ASMBS).

To be a viable candidate, you should also be ready to re-learn your dietary habits. New dietary habits can help ensure the surgery has positive and lifelong effects.

Before your surgery, you need to make plans for a special diet to follow both pre- and post-surgery.

The pre-surgery diet is geared toward reducing the amount of fat in and around your liver. This reduces the risk of complications during the surgery.

After the surgery, your doctor will tailor the general diet guidelines for you. The post-surgery diet usually consists of several weekly phases. It helps you recover, meet the needs of your now smaller stomach, and gain healthier eating habits.

Diet before your surgery

Losing weight before surgery helps reduce the amount of fat in and around your liver and abdomen. This may allow you to have a laparoscopy rather than open surgery. Laparoscopic surgery is less invasive, requires much less recovery time, and is easier on your body.

Losing weight prior to surgery not only keeps you safer during the procedure, but it also helps train you for a new way of eating.

Your exact eating plan and pre-op weight loss goal will be determined by your healthcare provider and likely with the help of a registered dietitian.

Your eating plan may begin as soon as you’re cleared for the procedure. If sufficient weight loss doesn’t occur, the procedure may be postponed or canceled. For this reason, you should start the diet plan as soon as you can.


Guidelines will vary from person to person, but they may include the following:

. Eliminate or reduce your intake of saturated fats, including whole milk products, fatty meat, and fried foods.

. Eliminate or reduce your intake of foods that are high in carbohydrates, such as sugary desserts, pasta, potatoes, bread, and bread products.

. Eliminate high-sugar beverages, such as juice and sodas.

. Exercise portion control.

. Avoid binge eating.

. Don’t smoke cigarettes.

. Avoid substances not recommended by your doctor.

. Avoid alcoholic beverages.

. Don’t drink beverages with your meals.

. Take a daily multivitamin.

. Consume protein shakes or protein powder.

What to eat

The pre-op diet largely consists of protein shakes and other high-protein, low-calorie foods that are easy to digest.

Protein helps bolster and protect muscle tissue. This can help your body burn fat instead of muscle for fuel. Protein also helps keep your body strong, which can speed up recovery.

As the date for your surgery nears, you may need to follow a mostly-liquid or liquid-only diet. Based on your weight and overall health, your doctor may allow you to eat some solids during this time. These might include fish, watered-down hot cereal, or soft-boiled eggs.

Before the surgery, make sure you ask the anesthesiologist for instructions about what you can or can’t have before the surgery. These suggestions may vary depending on your situation. For example, your doctor may want you to drink carbohydrate-rich fluids up to 2 hours before surgery.

Diet after your surgery

The post-surgery diet plan consists of several stages. How long each stage lasts and what you can eat and drink will be determined by your healthcare provider or dietitian.

All stages stress the importance of controlling your portions. This habit will help you continue to lose weight and prepare you for how you’ll eat for the rest of your life.

Stage 1: Liquid diet

During stage 1, your nutritional intake is geared toward helping your body heal from surgery. Your diet can help you avoid postoperative complications.

For the first few days, you’re only allowed to drink a few ounces of clear liquids at a time. This helps your stomach heal without being stretched out by food.

After clear liquids, you’ll graduate to additional types of liquid, including:

. decaffeinated coffee and tea

. skim milk

. thin soup and broth

. unsweetened juice

. sugar-free gelatin

. sugar-free ice pops

Stage 2: Puréed diet

Once your doctor decides you’re ready, you can move on to stage 2. This stage consists of puréed foods that have a thick, pudding-like consistency.

Many foods can be puréed at home with a food processor, blender, or other device.

Spicy seasonings may irritate the stomach, so avoid these completely or try them one at a time. Avoid fruits and vegetables that have lots of seeds, such as strawberries or kiwi. You should also stay away from foods that are too fibrous to liquefy, such as broccoli and cauliflower.

Instead, choose foods that liquefy well, such as:

Fruits applesauce, bananas, canned fruits, peachesapricotspearspineapples, melons
Vegetables spinachcarrotssummer squashgreen beans
Protein yogurtcottage cheesericotta cheesebeef, chicken, turkey, white fish (codtilapia, haddock), scrambled eggs

Stage 1 baby foods (which don’t contain solids) and vegetable juices such as V8 are also convenient options.

However, at this stage, it’s important not to drink fluids with your meals.

Stage 3: Soft foods diet

You’ll probably eat nothing but puréed food for several weeks. Once your doctor decides you’re ready, you can start building soft, easy-to-chew foods into your diet. These may include:

. soft-boiled eggs

. ground meat

. baked or steamed white fish

. canned fruits, such as peaches or pears

It is important to eat small bites. Eat a little at a time and practice good portion control.

Stage 4: Stabilization

Stage 4 of the gastric bypass diet includes the reintroduction of solid food. It typically begins about 2 months after surgery.

Because your stomach is much smaller, you’ll still need to dice or chop your food into small bites. Large pieces of food may cause a blockage, which can lead to pain, nausea, and vomiting.

Introduce new foods slowly. That way, you can best determine which ones your stomach can tolerate and which ones to avoid. Eliminate any food that causes abdominal discomfort, vomiting, or nausea.

Foods and drinks to avoid in stage 4

Certain foods and drinks shouldn’t be attempted yet, such as those that are hard to digest. These include:

. fibrous or stringy vegetables, such as pea pods

. popcorn

. corn on the cob

. carbonated beverages, such as sodas and seltzer

. tough meat

. fried foods

. crunchy foods, such as pretzels, granola, seeds, and nuts

. dried fruit

. bread and bread products, such as muffins

About 4 months after surgery, you may be able to resume eating normally.

However, portion control is still important. Make sure your diet consists mostly of fruits, vegetables, lean protein, and healthy carbohydrates. Avoid unhealthy foods that are high in fat, carbohydrates, and calories.

Eating well means you can enjoy continued health without putting weight back on.

Overall guidelines for a post-op diet

The guidelines for your postoperative diet will also serve you throughout life. They include:

. Eat and drink slowly.

. Practice portion control.

. Listen to your body. If you can’t tolerate a food, such as something spicy or fried, don’t eat it.

. Avoid high-fat and high-sugar foods.

. Enjoy beverages between meals, but not during meals.

. Drink enough daily to avoid dehydration.

. Eat only small pieces of food at a time and chew each piece thoroughly.

. Take the vitamins your doctor recommends.

Lifestyle changes after your surgery

You may feel motivated to begin or resume an exercise program. Right after surgery, you need to let your body heal. Go slowly.

Low-impact exercises are a good option for the first month. These include walking and swimming. You may also benefit from simple yoga poses, stretching, and deep breathing exercises.

Over the next several months, you can slowly build up to strength training and cardio workouts.

Think in terms of movement as well as exercise. Simple lifestyle changes can be physical fitness boosters, such as:

. walking instead of riding the bus

. parking farther away from your destination

. taking the stairs instead of the elevator

Possible complications of the surgery

Following the proper pre- and post-surgery diets can help you avoid complications, such as dehydration, nausea, and constipation.


Sometimes the connection between your stomach and intestines can become narrowed. This can occur even if you’re careful about what you eat.

If you have nausea, vomiting, or stomach pain for more than 2 days, let your doctor know. These are all symptoms of a possible obstruction.

Dumping syndrome

Portion control, eating and drinking slowly, and staying away from high-sugar, high-fat foods can also help you avoid what’s known as dumping syndrome. Dumping syndrome occurs if foods or beverages enter your small intestine too quickly or in too-large amounts.

Eating and drinking at the same time may also cause dumping syndrome. This is because it increases intake volume.

Dumping syndrome can happen at any stage of the post-op diet. Symptoms include:

. sweating

. nausea

. vomiting

. dizziness

. diarrhea

To help avoid dumping syndrome, a good rule of thumb is to take at least half an hour to eat each meal.

Choose low-fat and low- or no-sugar foods. Wait around 30 to 45 minutes before drinking any liquids, and always sip liquids very slowly.

The bottom line

Gastric bypass surgery can give you a new start toward health and fitness.

Following the recommended pre-op and post-op diet will go a long way toward your success. The right diet can protect you from surgical complications and teach you how to eat and drink well for the rest of your life.



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