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Dietary Information

Dietary Information for Weight Loss Surgery

Weight loss surgery is a tool to assist your weight loss journey, but it is not the whole solution. It is vital that healthy lifestyle behaviours are practiced to get the best results  from your surgery.

Pre surgery diet

In the time before your surgery, you will commence the pre-operative low calorie diet (also commonly known as the liver reducing diet). This diet will minimise surgical risk and assist to prepare you for the lifestyle change required after surgery. Your surgeon will discuss with you the length of you pre-operative diet, this is usually 2 weeks.

We have a food-based, calorie and portion controlled diet option or a meal replacement (Optifast) option. More detailed information will be provided to you during your appointment with the dietitian, and their ongoing support will be available to you during this period of preparation. 

Post surgery diet

After your operation, you will be able to tolerate drink liquids. The liquid phase of the diet lasts for about 1 week, before you progress to sloppy/pureed and soft foods over the next 4-5 weeks, and then eventually back to normal textures by around 6 weeks after surgery. It is very important that you follow the recommended diet, as this allows your body to heal and relearn how to process food again. It will also take time to get used to the new portion sizes you will be able to eat. Gradually moving from one consistency of food to another helps your brain catch up to the fact that your stomach is smaller.

What is meant by the different consistencies?

  • Fluids - any smooth liquid with no lumps. E.g. milk, drinking yoghurt, broth, and supplement fluids such as Optifast.
  • Sloppy/pureed foods – thicker smooth food that does not require chewing. E.g. mashed potato, Weetbix with lots of milk added, soup put through a blender until smooth, meat pureed with sauces and gravy’s, pureed/mashed fruit (without skins, pips and seeds),
  • Soft food – foods that are easily mashed with a fork. E.g. well-cooked vegetables, flaked fish with sauce, slightly mashed lentils, peas and beans, and scrambled or poached eggs.

Although this may seem daunting, in reality it is a lot easier than it sounds, as you probably won’t feel hungry after your surgery.

How often should I eat?

In the first 6 weeks try to eat three small meals - (snacks should be discussed with your dietitian). Your appetite will be suppressed as your body recovers from surgery so it is easy to forget to eat at all. Try to get into a routine that will prompt you to eat regularly. If you go too long without eating you can feel lightheaded.

What are the tips regarding eating?

The most important thing is to eat slowly and take your time chewing your food well. We are generally not very good at doing this as we rush our meals and often don’t concentrate on eating. Slowing down will make it easier to pinpoint when you have eaten enough. This will reduce the chance of over-eating, which can lead to feelings of sickness and discomfort.

Will my diet be balanced?

Your diet after surgery is very limited regarding the quantity of food that you can eat as well as the types of food. This can make it difficult to achieve a totally balanced diet in the first few weeks. However, over time you will find it easier to eat a variety of foods. It is important that you are conscious of the types of food you choose to eat. We suggest you concentrate on eating sufficient lean protein, vegetables and fruit. Your dietitian will be happy to help you with suggestions on how to do this.

It is recommended to take nutrient supplements after surgery to achieve a balanced intake. Supplements can range from a basic multivitamin for the non-malabsorptive procedures, like the gastric band, or specific nutrients such as iron, folate, calcium and vitamin D for the procedures that involve some malabsorption such as the gastric bypasses and sleeve gastrectomy. Supplementation is life-long after surgery and can be discussed with your surgeon and dietitan.

After six weeks what then?

After weight loss surgery, although your portions are smaller, the aim is to eat a variety of tasty and nutritious foods. We often take in wasted calories from food that we don’t particularly enjoy and are eating out of habit. With your new lifestyle, every mouthful of food should be enjoyable and full of nutrients. The aim is to not think of foods in terms of calories and fat but rather looking to maximise protein, iron, calcium and other nutrients. This really is a time of experimenting and perhaps trying foods that you may not have had before.

Tips for long-term lifestyle change

  • Be mindful – keep a food diary with a focus on portion sizes and food variety. This can help you build a habit of being aware of what you eat, which is important for health and weight loss and maintenance. This is especially useful if you lead a busy social and working life.
  • Always be positive about the good changes you have made to the way you live, even if they are small.
  • Try to manage stress in ways that do not harm your healthy lifestyle. Exercise is a great stress reliever, but you may also look into other forms of stress relief such as reading, self-pampering, socialising, or taking up a new hobby.
  • Do not focus just on the scales. It is important to think about your health as a whole - what else is improving as a result of the changes you are making? Keep a list and remember to keep your goals realistic and achievable.