Nutritional Guidelines for Weight Loss Surgery


Obesity is a lifelong disease and there is no operation, diet or medication that can by itself offer a permanent cure. Surgery with good aftercare and moderate lifestyle changes can give wonderful long-term results for health and weight.

Bariatric surgery is not a magical prescription for weight loss. It is an excellent tool to help the patient to limit his food amount and facilitate weight reduction. It is only the first step towards a major re-adjustment in life style, where the patient needs to adapt a healthy diet and a physical activity plan that suits him the best. The healthy diet aim for starts from choosing healthy foods to the way the patient eats those foods to achieve maximum success and help him lose weight safely.

A new way of life – A new way to eat

It is very important to follow the recommended dietary guidelines after undergoing bariatric surgery. These guidelines were carefully designed by the health care providers, with the goal of limiting the amount of calories consume, while providing balanced meals that help prevent nutrient deficiencies and preserve muscle tissue. This new way of eating may seem overwhelming at first, but over time, most patients find the guidelines become an unconscious part of their daily routine.

The Primary Nutrition Goals After Surgery:

  • Learn proper eating habits that will promote weight loss while maintaining health at a reduced weight.
  • Consume adequate amounts of protein to minimize loss of lean body mass and hair loss, facilitate healing and maintain skin elasticity.
  • Take adequate amounts of fluids to maintain hydration.
  • Obtain adequate nutrients for optimal health through supplementation.

Diet recommendations after bariatric surgeries may vary between medical centers. Most commonly, the diet has five phases, which serves many objectives. First, to allow stomach to heal without being stretched by the food intake. Second, to get the patient used to eat smaller amounts of food that can be digested comfortably and safely in smaller stomach. Finally, to ease the way back to eating solid foods after surgery. The meal plan will be high in protein to help the healing process, promote weight loss and preserve lean body mass (muscle), also be low in fat (5 grams or less per serving) and low in sugar (14 grams or less per serving).

The Diet will be advanced gradually, depending on tolerance:

Phase I     Clear liquid diet (in hospitalonly)
Phase II    Full liquid diet (1-2 weeks)
Phase III   Puree diet (1-2 weeks)
Phase IV    Soft diet (1-2 weeks)
Phase V     Regular balanced diet

General Guidelines to be Followed Throughout the Phases:

Healthy lifestyle choices give the best results for health and Quality of Life after surgery. To ensure that the patient get enough protein, vitamins, minerals and keep weight-loss goals on track, throughout each phase:

  • Eat small frequent meals: During the diet progression, Patient advised to eat many small meals a day and sip liquids slowly throughout the day (not with meals). When following a regular diet, decrease to three main meals and two snacks a day. Each meal should include about a half-cup to a cup of food. Advised to eat only the recommended amounts and stop eating when feel full. For the first 6 months following surgery, the calorie intake should be between 600 and 800 calories a day. Daily caloric intake should not exceed 1,000 calories for the first year. For successful weight loss, caloric intake may range between 800-1200 calories each day.
  • Take the vitamin and mineral supplements recommended by doctor: Because a portion of small intestine is bypassed after surgery, the body won’t be able to absorb enough nutrients from food. As a result, the doctor will recommend certain supplements for the patient. Patient should take these supplements as directed by his doctor every day.
  • Drink liquids between meals: Drinking liquids with meals can cause pain, nausea and vomiting as well as dumping syndrome. Expect to drink at least 6 to 8 cups (1.4 to 1.9 liters) of fluids a day to prevent dehydration. It is a good idea to avoid caffeine (Diuretic) for at least the first thirty days after surgery while the stomach is extra sensitive. We strongly warn against drinking any alcoholic beverages. After surgery, alcohol is absorbed into the system much more quickly than before, making its sedative and mood-altering effects more difficult to predict and control. Dehydration occurs when the body does not get enough fluid to keep it functioning at its best. Also fluids are required to burn its stored fat calories for energy. Carry a bottle of water all the day even there is no feel of thirsty. Signs of dehydration can be thirst, headache, hard stools or dizziness upon sitting or standing up.
  • Eat and drink slowly: Eating or drinking too quickly may cause dumping syndrome (when foods and liquids enter small intestine rapidly and in larger amounts than normal, causing nausea, vomiting, diarrhea, dizziness and sweating). To prevent dumping syndrome, choose foods and liquids low in fat and sugar, eat and drink slowly, and wait 30 minutes before or after each meal to drink liquids. Take at least 30 minutes to eat meals and 30 to 60 minutes to drink 1 cup of liquid. It is important to know that following surgery, stomach size is very small – less than 1/4 cup, or about the size of an egg. The opening that allows food to pass out of the stomach is also very narrow. For this reason, it is important to take only two to three sips or bites at a time of any new food and then wait 10 minutes before taking more. This will help to learn the limits and tolerance. Liquids will empty faster from the stomach than soft solids. If overeat or eat too quickly, may experience nausea or pain.
  • Chew food thoroughly: The new opening that leads from stomach into intestine is very small, and larger pieces of food can block the opening. Blockages prevent food from leaving stomach and could cause vomiting, nausea and abdominal pain. Take small bites of food and chew them to a pureed consistency before swallowing.
  • Try new foods one at a time: After surgery, certain foods may cause nausea, pain, vomiting or may block the opening of the stomach. The ability to tolerate foods varies from one person to another. Advise the patient to try one new food at a time and chew thoroughly before swallowing. If a food causes discomfort, don’t eat it. As time passes, he will be able to eat this food. Foods and liquids that commonly cause discomfort include meat, bread, pasta, rice, raw vegetables, milk and carbonated beverages. Food textures not tolerated well include dry, sticky or stringy foods.
  • Focus on high-protein foods: Immediately after surgery, eating high-protein foods can helps heal wounds, regrow muscle and skin, and prevent hair loss. High-protein, low-fat choices remain a good long-term diet option after surgery, as well. Try adding lean cuts of beef, chicken, fish or beans to the diet. Protein-rich foods are important, patients advised to take 60-100 g of protein daily. Protein should be taken in multiple doses, across multiple meals or healthy snacks. The body cannot absorb more than approximately 30 grams at once. Also, protein is a nutrient that helps us feel fuller, longer. The body needs additional protein during the period of rapid weight loss to maintain muscle mass. Protein is also required for the metabolism to occur. If the patient doesn’t have enough protein in the diet, the body will take its protein from the muscles and the patient will become weak
  • Avoid foods that are high in fat and sugars: After surgery, it might be difficult for the digestive system to tolerate foods that are high in fat or added sugars like fried foods, soda, candy and candy bars, and ice cream, so try to avoid these foods. The American Society for Metabolic and Bariatric Surgery (ASMBS) warns patients to avoid excessive carbohydrate intake, such as starchy foods (breads, pastas, crackers, refined cereals) and sweetened foods (cookies, cakes, candy, or other sweets). Limiting carbohydrates to 50 grams per day or less helps avoid rebound hunger problems which can lead to weight regain.

If the patient follows the dietary and exercise recommendations within the first two years following surgery, he can expect to lose 50 to 60 percent of his excess weight. If he continues to follow these recommendations, he can keep most of that weight off for a long term. People who regain weight after bariatric surgeries usually are consuming too many high-calorie foods and beverages and don’t exercise enough. And rather than eating three meals a day and perhaps a planned healthy snack, some people eat food all day long.

Successful weight management requires the following healthy habits:

  • Reduce unplanned snacking.
  • Exercise regularly.
  • Attend regular follow-up appointments with health care provider to review the symptoms and progress and to make sure the patients don’t have any vitamin or mineral deficiencies.
  • Follow all the instructions mentioned earlier.



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