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Preparing for success: The role of the preoperative diet in weight loss surgery

Patients pre-operative milk diet meal

The preoperative diet for weight loss surgery is an essential part of the preparation process. The liver reduction diet, also referred to as the LRD, is a specific dietary plan designed to reduce the size of the liver before weight loss surgery, particularly procedures like Gastric Bypass and Gastric Sleeve surgery. The LRD is often referred to as the milk diet as it It is based on milk, yogurt and fruit. In this blog, we’ll explore the importance of the preoperative diet, its objectives, and some tips to navigate this critical phase of your journey to a healthier you.


The purpose of the preoperative diet

Shrinking the liver

The liver stores glycogen, a form of energy. When you reduce your calorie intake through the preoperative diet, your liver begins to release this stored glycogen. This shrinking of the liver makes the surgical area more accessible during the procedure, reducing the risk of complications.


Preparing your body

By sticking to a restrictive diet for a few weeks, you can help your body adapt to the upcoming changes in your eating habits post-surgery. This can make the transition smoother and increase your chances of long-term success.


Reducing surgical risk

As a result of losing some weight before surgery, you can reduce the risk of complications during the procedure such as excess bleeding and difficulty accessing the surgical site.


Key components of the LRD

Low-calorie intake

The primary goal of the LRD is to help patients lose some weight before surgery. This often involves a significant reduction in calorie intake. The duration of this diet can vary but is usually recommended for around two weeks leading up to the surgery.


High-protein foods

Protein is essential for preserving muscle mass during rapid weight loss. You should make sure that you include lean sources such as chicken, fish, tofu, and beans in your daily meals.


Low-carbohydrate foods

By reducing your carbohydrate intake, it helps your body burn fat for energy. Include complex carbohydrates such as vegetables and whole grains while minimising refined sugars and processed foods in your diet.



Staying adequately hydrated is crucial. Patients are encouraged to drink plenty of water during the LRD. Avoid sugary drinks and excessive caffeine.



Your doctor may recommend specific vitamins and minerals, like calcium and iron, to prevent deficiencies after surgery. Ensure you take these as prescribed.


Portion control

Learning to control your portion sizes is a key skill which will be vital after surgery when your stomach’s capacity is significantly reduced.


Meal frequency

Dividing your daily intake into multiple small meals will help you to manage hunger and maintain steady energy levels.


Tips for a successful preoperative diet

Start early

Ideally, begin your preoperative diet several weeks before the surgery. This allows you to lose some weight and shrink your liver effectively.


Contact your healthcare provider for guidance

Consult with your surgeon and dietician to create a personalised diet plan that aligns with your specific needs and goals.


Stay committed

Commitment is key. Stick to your preoperative diet plan rigorously to maximise its benefits.


Stay positive

Stay positive and make sure that you focus on the long-term benefits. Remember that this phase is temporary and a crucial step towards a healthier future.


Seek support

If you need emotional support during this challenging phase, reach out to support groups or mental health professionals.


The preoperative diet is not just a requirement before weight loss surgery; it’s a vital step in ensuring a successful outcome. The LRD helps prepare patients both physically and metabolically for weight loss surgery. By following your healthcare provider’s guidance, staying committed, and maintaining a positive attitude, you will be able to set yourself up for long-term weight loss success. Remember, your journey doesn’t end with surgery; it’s just the beginning of a healthier, happier you.

If you any concerns or questions about the preoperative diet it is important to speak to your specialist team, who will be able to support you throughout your weight loss surgery journey.

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