Guidelines for your Diet – Before and Life After Bariatric Surgery

Before Weight Loss Surgery

To prepare for weight loss surgery, you will meet with a registered dietitian specializing in bariatrics and weight management to assist you in preparing for your journey while meeting the requirements of your insurance plan. During the pre-operative nutrition visits, the Einstein Bariatrics dietitian will guide you in starting to make lifestyle changes in your diet and activity pattern. You will also learn all the specifics of the weight loss surgery diet and the nutritional skills to help you follow the diet before and after surgery. You will also be provided with information on the vitamins and minerals that you will need to start taking lifelong after weight loss surgery.

Pre-Surgery Nutritional Preparation

  • Eating three meals per day — Avoid skipping meals
  • Protein, Protein, Protein — Learn how to include protein at meals and snacks
  • Decrease portion sizes – Start using smaller plates and bowls
  • Choose healthier options when dining out – Limit fast foods
  • Eat more plant foods – Aim for at least five servings of fruits and vegetables each day
  • Begin to move more – Get started on an exercise routine
  • Drink more water – Find alternatives to sweetened, carbonated beverages
  • Practice “mindful eating” – Pay attention to your stomach and stop eating when you are no longer hungry
  • Practice chewing your foods thoroughly before swallowing – Take at least 20 minutes to eat
  • Practice sipping your fluids – Do not chug or gulp your liquids
  • Practice eating and drinking separately – Not drinking 30 minutes before your meals, during your meals and 30 minutes after your meals

Once your date for surgery is all set, you will follow a specific diet for the two weeks before your surgery date. The 14-day pre-operative diet will consist of unlimited non-starchy beverages, protein shakes, and unsweetened beverages. This special pre-operative diet will improve your surgeon’s ability to perform the weight loss surgery procedure safely while jump-starting your weight loss at the same time.

After Weight Loss Surgery

You did it! Your weight loss surgery is complete, and your journey to healing begins on day one. You will need to make sure you follow the post-operative diet strictly to avoid any diet-related complications, and consult with your Einstein Bariatrics dietitian with any questions about food, portion sizes, your dietary intake, and overall nutritional value of your diet. To start, it is all about liquids and proteins!

Phase One (Day 1 through 7 – After Surgery)

Your goal for the first week after surgery is to stay hydrated! Aim for six to eight cups of fluids each day. You will feel full after drinking only a few ounces. Remember to sip slowly and do not drink more than eight ounces in an hour. Liquids need to be sugar-free. Protein shakes can start on day three, but only one shake per day.

Phase Two (Days 8 through 14 – After Surgery)

During this next phase of the post-operative diet, you will be able to have full liquids: milk products, smooth low-fat yogurt, thin hot cereals, and cream soups. Protein shakes increase to two shakes per day and you will work towards the goal of six to eight cups of fluids each day. It is important to continue to sip slowly on liquids – only four tablespoons or ¼ cup at a time.

Phase Three (Days 15 through 21 – After Surgery)

During this week, you will begin to eat three meals per day consisting of only pureed proteins and you will start taking vitamins and minerals. Portions will be ¼ cup, three times per day of protein-rich foods such as fish, turkey, chicken, beef, eggs, and beans. You will need to not drink 30 minutes before a meal, during a meal and thirty minutes after a meal.

Phase Four (Days 22 through 27 – After Surgery)

During phase four of the diet progression, you will continue to eat three meals per day, but add a soft side food to your meal. Your foods at this phase should be soft and mash-able with a fork. Your side foods might include canned fruit packed in water, well-cooked vegetables, unsweetened applesauce, and seafood. It is important to always eat your protein food first, followed by your side food. Your meal size is about ½ cup at this phase (¼ cup protein, ¼ cup side food).

Phase Five through Eight – the Second Month After Surgery

During the next four weeks, you will gradually increase the consistency of foods in your diet and the variety of foods you are eating (a little at a time). You will continue to include two protein shakes per day through phase eight after surgery to meet your goals of drinking six to eight cups of fluid and consuming 60 to 80 grams of protein daily. Each day, one to two new foods should be added to your diet. You will start to include in your eating plan whole grain toasts and cereals to your meals along with raw fruits and vegetables.

Your New Way of Eating

You are well on your way to a new, healthier lifestyle! Your long-term success will depend on how well you stay focused on a new way of eating. Some keys to success:

  • Always chew your food thoroughly. Take small bites and chew to a pureed consistencyy
  • Separate drinking and eating by 30 minutes
  • Aim for eight cups (64 ounces) of fluid each day. Stay away from carbonated and sugary beverages
  • Eat mindfully. Listen to your body and focus on how you feel. Hunger and fullness will be different than before your surgery
  • Use smaller plates and bowls
  • Measure your foods
  • Protein, Protein, Protein! Every meal and snack should include a protein. Always eat your protein food first, followed by a serving of fruit or a vegetable
  • Avoid alcohol after weight loss surgery
  • Include fiber-rich foods in your diet for fullness, heart health, and bowel regularity

Common Nutrition Concerns after Surgery

After weight loss surgery, some patients may experience some nutritional complications related to their dietary intake. Your Einstein Bariatrics dietitian will work with you on strategies to prevent and/or treat any diet-related concerns.

  • Food Intolerances – Some foods are not well tolerated initially. Such foods include untoasted bread, dry fibrous meats such as chicken and steak, pasta, rice, stringy vegetables, skins of fruit, and fried foods
  • Dumping Syndrome – Dumping syndrome is when food is “dumped” into your small intestine without being digesting after gastric bypass surgery. Eating foods high in concentrated or simple sugars and/or fat can lead to dumping
  • Bowel changes – Loose stool or diarrhea may occur at times related to dumping syndrome, intake of sugar alcohols, or possibly lactose intolerance. Patients may experience constipation which may be affected by fluid intake, activity levels, fiber intake, and iron intake.


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