Pre-op and post-op weight loss surgery diets for vegetarians, vegans and gluten free

Estimated Reading Time: 12 minutes

If you already follow a special diet such as vegetarian, vegan or gluten free, then you may wonder if there are healthy pre and post-operative diets to ensure your weight loss surgery is successful.You’ll be pleased to know that continuing to follow these special diets is entirely possible if you choose to have weight loss surgery. The key to making your bariatric surgery successful is enjoying a wide variety of protein sources, getting creative and having fun finding new tasty combinations. It is useful to talk to a dietician or nutritionist who can give you specific advice for your individual requirements. If you are well-planned it is more likely you will stick to your diet, stay healthy and ultimately succeed with your weight loss targets.

1. The importance of protein

Your pre-op and post-op bariatric diet will focus on protein. Protein is needed by your body to function properly. Unlike fat and carbohydrates, protein is not stored by your body and so it needs to be eaten in sufficient quantities every day. The protein needs of a bariatric patient can range from 46 to 100 grams of protein per day depending on weight, gender, age and surgical procedure.

2. Vegetarians

There are ample vegetarian foods to consume in your pre and post-bariatric diet. In fact choosing meatless meals can decrease your intake of saturated fat and cholesterol, as well as increase your intake of heart-healthy unsaturated fats and fibre.

a) What is a vegetarian?

Vegetarian refers to those who abstain from animal products. The Vegetarian Society defines a vegetarian as: "Someone who lives on a diet of grains, pulses, nuts, seeds, vegetables and fruits with, or without, the use of dairy products and eggs. A vegetarian does not eat any meat, poultry, game, fish, shellfish or by-products of slaughter." ¹

b) Vegetarian protein sources

As a vegetarian you will need to pay extra attention to eating enough protein in every meal. Non-meat foods usually have less protein per ounce than meat which means there is less room in your stomach for non-protein foods. Many foods including beans, tofu and even vegetables like broccoli contain protein. If you eat eggs and dairy products, consuming enough protein shouldn’t be difficult. Some variations of vegetarianism may be more challenging to ensure adequate protein is included in the diet but with forward planning this is achievable.You may not realise some foods contain such a high percentage of protein. Listed below are a few foods showing the percentage of calories from protein (value per 100 grams of edible protein)²:• Kidney beans 58%• Soybeans 35%• Tomato 19%• Lentils 34%• Mushrooms 56%• Spinach 50%• Watercress 84%• Broccoli 33%• Lettuce 36%• Cauliflower 32%The best vegetarian diet is varied and does not depend on one specific food type as its main source. The following list offers some tasty suggestions on healthy, vegetarian protein sources:• Eggs – on average eggs have six grams of protein and provide healthy fats.• Dairy – cottage cheese, yoghurt, and other unsweetened dairy products are excellent vegetarian protein sources.• Soy products – tofu, tempeh, and edamame are all excellent protein sources. Flavour plain soy products yourself for a healthier option.• Legumes – protein-rich and high in fibre, beans, lentils, and peas should be a staple in vegetarian and non-vegetarian diets alike. Use them in stews or soups, as side dishes, or blended into creamy dips.• Nuts – provide a boost of healthy fibre and fat but they are high in calories and should be eaten in moderation.• Seeds – try including these high-fibre, protein packed seeds in your diet in the form of quinoa, millet, or teff.• Whole grains – whilst they may not offer a lot of protein, they are high in fibre and can often complete other plant proteins. Enjoy in moderation healthier options like brown rice, sorghum, kamut, and farro.

c) Pre-operative vegetarian diet

Your bariatric surgeon may recommend a pre-operative diet to get you ready for surgery. This diet will be high in protein, but low in calories, fats, and carbohydrates, especially refined sugars and saturated fat. Your surgeon will provide advice for your pre-operative vegetarian diet.

d) Vegetarian options through the diet phases

Your bariatric surgeon or dietician will probably give you a meal plan. You can substitute vegetarian options for the items on your standard post-op meal plan. Here are some options:Clear liquids- Prepare vegetarian broths instead of meat ones. Skip the Jell-O as it’s made from the hooves of horses and cows.Full liquids- Try low-fat cream soups, skimmed milk, yoghurts and protein shakes.Pureed foods- Puree things like beans, tofu and vegetarian chilli. Include foods such as egg whites, yoghurts, soft fruits and vegetables and cottage cheeses that are blended with water, fat free milk, juice with no added sugar and vegetarian broth.Soft foods- For vegetarians soft protein foods include canned or soft fresh fruit, cooked vegetables, eggs, yoghurt, cottage cheese and soft cheese. Avoid peanut butter and pasta as they are often too sticky for your new stomach to tolerate. Don't eat crunchy nuts or hard cheeses yet as your stomach wont able to digest them.Solid Foods- Vegetarians can eat any legumes especially beans, lentils, split peas and tofu. These are excellent protein sources and low-fat foods. Include at least three ounces of protein at each meal such as eggs, cottage cheese, beans or tofu. Don't fill up on high-fat cheese instead of well-balanced meals. During the first three months avoid hard-to-digest foods including raw vegetables, apple skins and nuts. Your maintenance diet will focus on protein, fruits and vegetables and avoiding junk food or empty calories.

3. Vegan

If you are a vegan about to have weight loss surgery you can be assured there is ample variety of proteins to consume for success in your post-bariatric diet³. A vegan diet requires a lot of variety, because the proteins are not complete.

a) What is a vegan?

Veganism is a way of living which seeks to exclude, as far as is possible and practicable, all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose. They have a plant-based diet avoiding all animal foods such as meat, dairy, eggs and honey. A vegan diet is richly diverse and comprises all kinds of fruits, vegetables, nuts, grains, seeds, beans and pulses⁴.

b) Vegan protein sources

The biggest source of protein in most vegan diets is soy. Soybeans are generally low in carbohydrates and a high fibre source of protein. Soy also supplies iron, vitamin K, magnesium, copper, manganese, riboflavin and a variety of phytonutrients. Soybeans are versatile as they can be eaten right out of the pod, dried, in the form of tofu or as soy milk.Tofu can be prepared in many different ways. It is great for post bariatric surgical diets because it is soft, easy to digest and it takes of the flavour of what it is cooked with.

c) Pre-operative vegan diet

If your surgeon recommends a pre-surgery diet it will probably be a liver shrinking diet which is low in dietary carbohydrate and fat and should be easy to follow on a vegan diet. Your surgeon or dietician will offer guidance for this diet as a vegan.

d) Vegan options through the diet phasesafter weight loss surgery

Here are some options for the diet phases you will move through as you work towards solid foods following your bariatric surgery:Clear Liquids- Prepare vegetable based broths instead of meat ones.Full Liquids- Use soy milk instead of skimmed milk in protein shakes. Use a soy protein powder instead of one made with whey, which is a milk product. Substitute regular yoghurt with soy yoghurt.Pureed Foods- Puree soy products, legumes, soft fruits and vegetables and whole grains with water, fat free soy milk (read the nutrient label first as soy milk often has added sugars), juice with no added sugar and vegetarian broth.Soft foods -For vegans soft protein foods include legumes, soy products, canned or soft fresh fruit, cooked vegetables and whole grains such as brown rice and farro. Don't eat crunchy nuts at this stage as your stomach is not yet able to digest themSolid Foods- Vegans can eat any legumes especially beans, lentils, split peas and soy products such as tofu, vegetables and fruits, nuts in moderation, seeds and whole grains.Since plant-based foods are less protein-dense vegans may need to use protein supplements for a longer period of time to meet their daily goal of protein per day. A vegan diet has a risk of a Vitamin B12 deficiency which leads to increased levels of homocysteine and has been linked to heart disease and increased risk of stroke.Other essential vitamins and minerals may not be consumed in appropriate quantities without supplementation. These deficiencies will vary between patients and their lifestyles. If you pursue a vegan diet and weight loss surgery it is best to be tested for vitamin and mineral deficiencies regularly.

4. Gluten free diets

a) What is gluten?

Gluten is a protein found in wheat, rye, barley and many processed foods including pasta, breads and cereals.

b) Why choose a gluten free diet?

Some people avoid gluten because they have Celiac disease, an auto-immune disorder whereby gluten damages the small intestine lining and results in abdominal pain, bloating, nausea and diarrhoea.Other people avoid gluten because of gluten intolerance. Gluten intolerance mimics symptoms of Celiac disease without the immune response.It is thought that the trauma of surgery, including weight loss surgery, may lead to the body having an abnormal immune response to eating gluten⁵.

c) Gluten free diet protein and fibre sources

If you are following a gluten free diet you will need to pay particular attention to your protein and fibre content.There are countless gluten-free whole grains that provide just as much fibre, or often even more, than foods containing gluten. These include quinoa, amaranth, buckwheat, millet, sorghum, teff and wild rice. Vegetables, fish, lean meats and poultry, low fat milk, eggs, beans and nuts are good protein sources if you are following a gluten free diet.

d) Pre-operative gluten free diet

Your surgeon may recommend a liver shrinking diet for you before weight loss surgery. For gluten free diets you can eat vegetables, fish, lean meats, poultry, beans and fruit which are low in dietary carbohydrate and fat.

e) Post-operative gluten free diet

You will need to plan your gluten free diet through the diet phases following your bariatric surgery. Meals should always include high-protein food items such as lean meat, yoghurt and eggs.Clear liquids - Initially after your surgery you will start with clear liquids such as water, tea, broths, diluted non-acidic fruit juices.Full liquids -Once your body tolerates these you will be able to move onto full liquids such as low-fat cream soups, protein shakes, plain skimmed milk and gluten free yoghurt.Pureed foods- The next phase is pureed foods and you can puree foods you would normally eat on a gluten free diet such as vegetables, fish, lean meats, poultry, low fat milk, eggs, beans, quinoa, amaranth and buckwheat.Soft foods- When you move onto soft foods they might include ground or finely diced meats, fish, canned (taking care to check the labels for the sugar content) or soft fruit, cooked vegetables, buckwheat, amaranth or other gluten free grains.Solid foods -Eventually depending upon your tolerance you will be able to move on to a solid food diet. Include a wide variety of plain meats, fishes, vegetables, fruits and gluten free grains such as quinoa, amaranth and wild rice. Gluten free grains will provide you not only with the protein you need but also the minerals such as calcium and magnesium and also fibre to maintain a healthy diet.Here you can find our guide prices for bariatric surgery.Read more weight loss surgery blog posts to find answers to the most common questions including: pros and cons of gastric balloon and gastric sleeve, how to choose a weight loss surgeon, exercise after weight loss surgery etc.

About Ramsay Health Care UK pre and post-operative bariatric diets

Ramsay Health Care is a leading provider of weight loss surgery in the UK. Ramsay offers weight loss procedures for patients who follow special diets such as vegetarian, vegan and gluten free.Weight loss surgery is performed at Ramsay hospitals by experienced bariatric consultants who are highly qualified and have undergone intensive specialist training.They will work in a multidisciplinary team who liaise with each other to provide the best plan of action for you. They include a dietitian who will meet with you and produce a bespoke eating plan, and specialist trained nurses who will be by your side during your journey to offer support and guidance to ensure that you achieve your goals.Contact us for more details.



Register your interest to hear from us