Gastric sleeve surgery, a clinically proven method for reducing body weight, involves decreasing stomach size to about 15% of its original volume. The effectiveness of this procedure relies heavily on both pre-operative and post-operative dietary plans. This article provides a comprehensive overview of the dietary guidelines before and after bariatric sleeve surgery, ensuring safety, promoting weight control, and minimizing potential complications.
Understanding Gastric Sleeve Surgery
Gastric sleeve surgery, also known as sleeve gastrectomy, reduces the stomach's size by approximately 75%, leaving a sleeve-shaped stomach. This restriction limits food intake, helping patients lose weight by promoting satiety with smaller portions. The smaller stomach, or gastric sleeve, reduces appetite and aids in long-term weight control. The part of the stomach that is separated from the sleeve no longer plays a role in the body’s digestive process.
The Importance of Pre-Op Diet
The pre-op diet is a food consumption plan implemented in the weeks leading up to the gastric sleeve procedure. This diet is crucial for several reasons:
- Enhancing Safety: It makes the procedure safer and easier.
- Reducing Complications: It lowers the risk of complications during and after surgery.
- Establishing Healthy Habits: It initiates the lifestyle changes necessary for long-term weight management.
Key Components of the Pre-Op Diet
In many cases, the pre-op diet should begin three weeks before the surgery. The primary goals are to reduce liver size, promote initial weight loss, and prepare the body for the upcoming changes. The liver sits on top of the stomach, and an enlarged fatty liver can make it harder for the bariatric surgeon to get underneath the liver to operate on the patient’s stomach, which can increase the risk of complications (this is especially important if the patient suffers from fatty liver disease).
Calorie Reduction: Reduce overall calorie intake, with a particular focus on carbohydrates. A low-calorie, low-carbohydrate diet is typically recommended for a minimum of two weeks prior to surgery. This diet aims to reduce liver size by depleting glycogen stores, making the liver less fatty and easier to manipulate during surgery. A special diet, usually lasting between 2 and 4 weeks, provides around 1000 calories and no more than 100g of carbohydrates a day. Patients can choose to follow a diet based around high protein, low carb foods, to calorie count, or to have meal-replacement shakes or milk and yoghurts instead. The liver reduction diet reduces surgical risks by making the procedure easier to perform, safer and improves postoperative recovery.
Read also: The Hoxsey Diet
Carbohydrate Restriction: Refined sugars, commonly found in candy and soft drinks, should be eliminated. Carbohydrates are a major contributor of calories to most diets.
Maximize Protein Intake: Consume at least 60 grams of protein daily. This is necessary for wound healing.
Focus on Healthy Fats: Incorporate healthy fats found in foods like fish, nuts, and olives. Limit other fats, such as those in butter or oils.
Hydration: Drink plenty of water in the weeks before the procedure to avoid dehydration.
Liquid Diet Transition: Two or three days before surgery, switch to an all-liquid diet consisting of water, broth, gelatins, and low-calorie sports drinks (no sodas).
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Fasting Before Surgery: Refrain from consuming anything, including water, starting at midnight on the day of surgery. You will be advised to be ‘nil by mouth’ from midnight the day before your surgery - this means not eating food for around 8 hours prior to the operation.
Medication Adjustments: Certain medications must be discontinued prior to surgery, as advised by your healthcare provider. It is very important that you communicate with your bariatric surgeon about any medications that you are on. Hormone replacement medications may need to be adjusted. If you are diabetic, contact your prescribing physician to discuss managing your diabetes medication during these 3 weeks.
The Liver Shrinkage Diet
Before undergoing gastric sleeve surgery, your surgeon and dietitian will advise that you follow a pre-operative diet designed to shrink your liver - this is known as a ‘Liver Shrinkage Diet’ or ‘Liver Reduction Diet’, and is often abbreviated to ‘LRD’. This special diet, usually lasting between 2 and 4 weeks, provides around 1000 calories and no more than 100g of carbohydrates a day. Patients can choose to follow a diet based around high protein, low carb foods, to calorie count, or to have meal-replacement shakes or milk and yoghurts instead. The liver reduction diet reduces surgical risks by making the procedure easier to perform, safer and improves postoperative recovery.
Additional Pre-Operative Recommendations
- Smoking Cessation: Quit smoking at least 4 to 6 weeks before surgery to improve overall health and reduce the risk of complications.
- Physical Activity: Increase cardiopulmonary function and muscle strength through a pre-surgical fitness plan to enhance recovery. Known as “prehabilitation,” a pre-surgical fitness plan can reduce your hospital stay, lower your risk for pneumonia and enhance your overall recovery.
Controversies and Considerations Regarding Pre-Operative Weight Loss
While the importance of pre-operative dietary changes is well-established, the necessity of significant pre-operative weight loss remains a topic of debate. Some studies suggest that a modest weight loss of 5-10% in the immediate preoperative period could facilitate surgery and reduce the risk of complications. However, current guidelines do not provide clear indications about pre-operative weight loss due to limited evidence.
- Conflicting Research: Some retrospective studies indicate that post-operative weight loss is higher in patients who achieve greater than 10% weight loss before surgery, while others find no significant difference in weight loss outcomes between those who lost weight and those who gained weight before surgery.
- Potential Benefits: A modest weight loss can reduce liver size and intra-abdominal fat mass, potentially decreasing blood loss, short-term complications, operation time, and length of hospital stay.
- Dietary Approaches: Very low-calorie diets (VLCD) and very low-calorie ketogenic diets (VLCKD) are frequently prescribed in the months leading up to surgery to induce weight loss.
Potential Side Effects of the Pre-Op Diet
During the initial days of the pre-op diet, some individuals may experience symptoms such as headaches, fatigue, and irritability. These symptoms are typically temporary reactions to the body adjusting to fewer calories and carbohydrates and should subside within 2-3 days.
Read also: Weight Loss with Low-FODMAP
Post-Op Diet: A Phased Approach
The post-op diet is as crucial as the pre-op diet for realizing the benefits of bariatric surgery and avoiding health complications such as diarrhea, nausea, vomiting, constipation, and gastric leaks. The bariatric recovery diet helps ensure that your body heals properly and receives adequate nutrition. Following your post-op diet is essential if you want to realize the benefits of a bariatric procedure. It will also help you avoid potential health complications, including diarrhea, nausea, vomiting, constipation, and gastric leaks.
Phase 1: Clear Liquids (Week 1)
During the first week after surgery, the diet is restricted to clear liquids. This phase is crucial for keeping you hydrated and allowing your wounds to heal. In addition to water, appropriate options include:
- Clear broth
- Decaffeinated beverages
- Sugar-free versions of drink mixes like Kool-Aid and Crystal Light
- Bone broth
Important Considerations:
- Avoid caffeinated, carbonated, and sugary beverages.
- Sip fluids throughout the day to reach a total of 1.5 to 2.5 liters.
- Aim for at least 1 liter of milk-based fluids.
- Prioritize protein-rich liquids over others.
Phase 2: Thicker Liquids (Week 2)
The second week involves the addition of thicker liquids to the diet. Examples include:
- Smooth soups (strained to remove lumps)
- Protein shakes
- Yogurt
Phase 3: Pureed Foods (Week 3)
Soft and pureed foods are introduced next. It is important to complete this stage as your stomach pouch will be very small and tight at first. Puree foods are smooth and can pass through your stomach easily. You will need to use a blender, liquidiser or food processor to puree your food to the correct consistency. Aim for a smooth consistency like ‘yoghurt’. Half your meal portion should be from a protein rich food. Start with 1-2 tablespoons at your meals and snacks, and if you feel comfortable gradually increase the amount. As you progress through the puree stage, you may find that your portions gradually increase. However, remember to stop eating at the first signs of fullness or if you feel uncomfortable. Choose foods that are high in protein to help you to meet your protein requirements (at least 70g protein each day). Eat 3 meals and 3 snacks each day. Examples include:
- Eggs
- Ground meats
- Fish
- Beans
- Cooked vegetables
- Soft fruits
Important Considerations:
- Blend or mash foods well to ensure a lump-free, yogurt-like texture.
- Eat three to four meals a day, starting with one to two tablespoons per meal, gradually increasing to a maximum of four tablespoons.
- Include protein in each meal.
Phase 4: Soft Foods (Week 4-7)
Once you have completed the puree stage you can move onto soft foods. Soft foods are foods that have a soft consistency, are well cooked and can be easily mashed with a fork. Eat 3 meals each day and if you feel hungry between your meals, then have a snack. Use a side plate for your main meals, and fill ½ of your plate with protein rich foods. Start with 3-4tbsp at meal times and stop eating at the first signs of fullness or if you feel uncomfortable. Remember to stop eating at the first signs of fullness or if you feel uncomfortable. Examples include:
- Soft cooked eggs
- Thick soups
- Minced or wafer thin meats
- Fish
- Cauliflower cheese
- Cottage cheese
- Tinned or soft fruit
- Scrambled eggs
- Cooked vegetables
- Rice and pasta (not overcooked)
Phase 5: Solid Foods (Week 8 Onward)
Solid foods are gradually reintroduced, with the post-op diet resembling the pre-surgical diet. After around 7 to 8 weeks, you should be able to resume a normal-textured, fairly solid, and healthy balanced diet. Your gastric sleeve will allow you to eat almost any type or texture of food, provided you chew the food well before swallowing, although some people do struggle with some textures e.g. white doughy bread, chewy meats, and sugary foods - as the latter trigger dumping syndrome. You should aim for three well balanced meals each day, topping up with a protein drink if needed. Certain items remain off-limits or should be consumed in small portions:
- Fried foods
- Candy
- Nuts
- Seeds
- Whole dairy products
- Breads
- Pastas
- Fibrous vegetables such as broccoli
Long-Term Dietary Focus:
- Prioritize lean protein, complex carbohydrates, and healthy fats.
- Avoid processed foods and sugar-added products.
- Post-surgery meals should be small but nutrient-dense.
- Eat three small meals a day with no more than five hours between meals.
- If you feel hungry between meals, take a drink first to ensure you’re not confusing hunger with thirst.
- Don’t eat until you are ‘full’.
- Don’t eat and drink at the same time.
General Post-Operative Eating Guidelines
- Eat slowly: put a small amount of food in your mouth at a time (size of a thumbnail) and chew this very well (at least 20 times).
- Do not eat until you are ‘full’.
- Do not drink with meals.
Potential Post-Operative Complications and Management
Dumping Syndrome: Avoid food and drinks high in sugar and fat, as these can cause dumping syndrome. Dumping syndrome occurs when fatty or sugary foods are emptied or ‘dumped’ from the stomach into the small intestine too rapidly. If you experience dumping syndrome then try to sit or lie down until your symptoms improve.
Vomiting: If vomiting continues and the cause cannot be explained, contact your surgeon or GP.
Hair Loss: During the first 6-9 months after your surgery, you will experience rapid weight loss and hair loss can occur.
Constipation: If you experience constipation make sure you are drinking enough fluids. You should aim for 1.5-2 litres of fluids each day.
Reactive Hypoglycaemia: The symptoms of reactive hypoglycaemia usually occur within 1-4 hours after a meal. If you think you are experiencing reactive hypoglycaemia then contact one the bariatric dietitians for advice, as reactive hypoglycaemia can often be managed with dietary changes. Keeping a food and symptom diary can be helpful to identify foods that trigger symptoms.
Vitamin and Mineral Deficiencies: After surgery reduced food intake may increase your risk of vitamin and mineral deficiencies. Daily, life-long vitamin and mineral supplementation is essential. As soon as you are able to start having liquids, you can begin taking your multivitamins and minerals. Remember to space your vitamins and minerals across the day, as taking them all together will affect how well you absorb them.
The Importance of Multidisciplinary Care
Achieving the best outcomes from gastric sleeve surgery requires a multidisciplinary approach. At Ramsay Health Care your weight loss surgeon will work in a multidisciplinary team who liaise with each other to provide the best plan of action for you. A bariatric dietitian plays a crucial role in optimizing nutritional intake both before and after surgery.