Long Term Diet After Gastric Bypass Surgery

Once you reach that six month post-op mark in your bariatric journey, your diet will transition from the post-surgery phase, to the life-long maintenance phase. The diet that immediately follows your procedure, commonly referred to as the “Phase 4” diet, is designed to help you recover from surgery and help you re-learn how to eat a healthy, balanced meal. It is not designed to sustain you long-term.

That is where the long-term post-op diet comes into play. And, where some patients might become confused as to what they can eat, how long they won’t be allowed to eat certain foods, and how much food, and therefore, calories they should be consuming with each meal.

Your bariatric journey doesn’t end six months after your surgery, and if you’re interested in learning more about the long-term diet after gastric bypass surgery, below are some important things to know.

Three Stages The Post-Op Diet

The diet bariatric patients follow after their procedure can be broken down into three different stages: Immediately Post-Op, Long-Term Weight Loss, and Lifelong Maintenance.

Immediately Post-Op

This is the “Phase 4” diet that is initiated immediately after a patient’s procedure. Patients transition through a 6 week dietary progression: a liquid diet of protein shakes for 2 weeks, a pureed food diet for 2 weeks, and finally 2 weeks of mechanically soft foods before arriving back at a regular diet. The dietary progression is low carbohydrates and high protein, and it’s crucial that patients don’t surpass the prescribed hourly and daily amounts or number of calories.

Patients will also see the most rapid weight loss in this stage. After surgery, patients are recovering, and generally don’t have much of an appetite anyway. However, with the strict calorie count that is usually vastly different from what patients would normally eat, they lose a large amount of weight very quickly.

Long-Term Weight Loss

This stage requires following a careful strategy developed and agreed upon by patient and dietician. The key is to develop a diet plan that will help the patient continuously lose weight while optimizing nutrition, but it must also be sustainable helping the patient develop healthy eating habits.

Patients are still moving towards their goal weight, however, they as time progresses they will see their weight loss slow down  until it eventually plateaus at their new healthier weight. This is why constant communication between patients and their dieticians is so important, because it can be easy for patients to fall back into their unhealthy eating habits once they are allowed to eat solid food. If this happens this can damage weight loss or even result in weight regain.

Generally, dieticians will recommend a diet of 900-1,200 calories per day during this phase. Patients can usually see a good amount of success as long as they stick to their calorie and protein counts daily.

Lifelong Maintenance

This is the last stage of the post-op diet, and it’s the longest and one of the most important. By now, patients have been working on developing new healthy eating habits with their dietician, and they can begin focusing on the long-term. They have reached their post-op goal weight, and now their focus has to shift to maintaining that weight moving forward.

At this point, the new habits that have been formed in stage one and two will help the patient maintain their new weight, and once the healthy goal weight has been reached, they should maintain the new weight neither gain nor losing significant weight after this goal has been reached.

Long-Term Diet Recommendations

Stage two and three of the post-op diet can sometimes initially feel like a significant change because rapid weight loss begins to slow down, and importantly patients need to start living their lifelong diet vs. a diet that only lasts a few months.

Each bariatric patient is different and each should consult their dietician and bariatric surgeon to learn recommendations that will help them have the most weight loss success. Below are a few recommendations that, generally speaking, can help patients learn about their long-term diet.

Plate Breakdown and Proteins

Your plate should consist of around 50 percent protein, 25 percent vegetables, and 25 percent starches. Your protein intake per day should be around 70-90 grams for men and 60-80 grams for women, and it helps if you eat the protein on your plate first. This way, if you start to feel full and like you can’t finish the entire meal, you’ve at least received your protein for that meal. Eventually by 3-6 months after surgery you should aim for each meal to be around 4-6 oz. of food, although initially after surgery you may only be able to tolerate around 2 oz per meal. When you reach the 4-6 oz. mark you want to avoid increasing this volume and you must avoid eating quickly both of which can stretch your gastric pouch and undo benefit.

Recommended Foods

Some foods that will help you feel full and account for the different macros you should be hitting are:

  • Lean meats (chicken and fish)
  • Eggs
  • Cottage cheese
  • Greek yogurt
  • Whole grains like oatmeal, brown rice, and buckwheat
  • Fruits
  • Avocadoes
  • Olive oil


Water is key in all stages of the post-op diet for two main reasons, although there are several more benefits to drinking enough water each day. The first is it will curb your appetite. Many times we think we are hungry, when really our body is dehydrated. It’s important to constantly be drinking water throughout the day in order to continue to feel full. Don’t chug a whole bottle of water when you feel thirsty. Instead, carry a bottle with you everywhere you go and take continuous sips.

The second important reason to stay hydrated is water is a necessary component for fat burning. This is especially important immediately after bariatric surgery when your body is still getting used to the new way you absorb food. Staying well hydrated can also prevent feelings of nausea that can arise when people become dehydrated.

Don’t Get Discouraged

As stated here, and probably by your surgeon, your bariatric journey is a marathon, not a sprint. Once you’ve made it through stage one directly after surgery, that’s when the lifelong work truly begins. However, it’s important to not feel discouraged. Rather than thinking of your new diet as a life of restrictions, consider it a second chance. A chance to change your life for the better and live with less weight and more energy.

Dr. Joshua Long headshot

This page was medically reviewed by Dr. Joshua Long, MD, MBA, FACS, FASMBS. Dr. Long is a double-board-certified bariatric surgeon and bariatric medical director for Parker Adventist Hospital.
Full Bio: Dr. Joshua Long, MD, MBA, FACS, FASMBS
Page Updated: November 18th, 2022

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