Definition and Overview

Gastric bypass surgery, one of the most common types of bariatric surgery, is an effective weight loss procedure. It is, in some ways, the last recourse for people who have tried everything to lose weight but failed. Gastric bypass surgery is highly effective in terms of losing weight because it changes how the stomach and the small intestine handle the food.

The procedure involves making the stomach smaller by dividing it into two sections: a smaller, upper pouch and a larger, bottom section. The upper pouch, which initially holds roughly 1 cup of food, is connected through a small hole in the small intestine. This makes you eat less because you have a smaller compartment. With a smaller stomach, you can only eat as much as one cup of food and then you’re full. This results in a variety of dietary and lifestyle changes that you have to go through once you’re done with the surgery. This is where gastric bypass nutrition comes in. Gastric bypass nutrition planning is required immediately after surgery because your stomach has to heal first and is not ready to deal with solid foods. Care is essential in making sure that the stomach is not pressured into functioning fully without proper preparation to avoid serious complications.

Over time, you will go from liquid food to soft food and then finally to solid food. This progress happens over a period of 3 to 6 months depending on how fast your stomach is adapting to the new nutrition plan.

Who Should Undergo & Expected Results

All patients who have undergone gastric bypass surgery are required to participate in a gastric bypass nutrition program. If weight loss was the reason you underwent the procedure, then it stands to reason that you want to work to keep it off in the future. Just because you now have a smaller stomach, it doesn’t mean that you can still continue eating the way you did before. There are adjustments to be made, some of them permanently, so you can avoid gaining unwanted pounds. How Does the Procedure Work?

Gastric bypass nutrition has several goals, but ultimately it helps to ease you back into eating regular solid foods after surgery. It also helps you to manage your diet and nutrition as part of a healthy lifestyle, one that will keep the weight off in the future.

The first goal is recovery after surgery. The goal is to introduce the right diet to ensure that the stomach will heal as quickly as possible. The surgery reduces your stomach capacity from about four cups of food to just one. This is a drastic reduction in the amount of food that you can consume per meal. Naturally, you can’t immediately go back to eating the whole amount of food immediately after surgery so you will only have liquid or pureed food to eat for the next 2 to 3 weeks. You will progress from clear liquids (about 2 to 3 ounces at a time) to other liquids like unsweetened juice or strained cream soup. Once you are able to tolerate liquids, you can move on to “eating” strained or pureed food, preferably with the consistency of a smooth paste. The second goal is to let you get used to eating smaller amounts of food that can be easily digested. This is the part where soft foods are introduced to your diet. This allows your stomach to accept small, tender, easily chewed pieces and prepares it for solid foods later on. Moving from liquids to soft foods gradually will help you get used to having frequent, smaller meals. This will be the kind of meal frequency that you’ll be looking forward to in the future.

After about eight weeks of consuming liquid and soft foods, your stomach will be ready for solid foods, and this is the final step on the way to your new normal eating habits. Foods still need to be in bite-sized pieces for easier chewing and there are some foods to avoid, like nuts, popcorn, fibrous vegetables, carbonated beverages, fried foods and bread because they may cause gastrointestinal problems. This is the third goal of gastric bypass nutrition – avoiding side effects and complications from surgery. You must exercise self-control when experimenting with the types of solid food that you want to eat. Remember that you have to give your stomach time to adjust to the different foods you eat and sooner or later, you may be able to eat those that are prohibited early on.

The final goal of gastric bypass nutrition is to keep you from gaining weight. To do that, you have to commit to a new way of eating and this involves:

  • Eating frequent, small meals
  • Eat slowly and chew your food properly
  • Do not drink while eating and 30 minutes after you eat but stay rehydrated throughout the day with as many as 8 cups of water a day
  • Eat a balanced diet with adequate fiber and protein
  • Instead of sweets, develop the habit of eating healthy snacks
  • Make sure to have vitamin/mineral supplements

Possible Complications and Risks

Gastric bypass nutrition does not pose any risk or complications. In fact, it helps patients recover from their surgery as quickly as possible and educate them on proper diet. Meanwhile, patients are at risk of suffering from complications when they force their stomach to eat more than it can hold, which effectively compromises the progress to health. It is the same if you don’t chew your food thoroughly or you eat foods that your stomach can’t digest well following the surgery. They will end up blocking the small hole that connects to your small intestine. You will end up being nauseous and may vomit to remove the large pieces blocking the hole. You will also experience abdominal pain.


  • Heber D, et al. (2010). Endocrine and nutritional management of the post-bariatric surgery patient: An Endocrine Society clinical practice guideline. Journal of Clinical Endocrinology and Metabolism, 95(11): 4823–4843.

  • Mechanick JI, Kushner RF, Sugerman HJ, Gonzalez-Campoy JM, et al. American Association of Clinical Endocrinologists; Obesity Society; American Society for Metabolic & Bariatric Surgery. American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient.

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