Dietary Guidance After Weight Loss Surgery

The post-bariatric surgery diet plays a key role in helping you recover smoothly and making your transition to solid foods easier.

Your diet after surgery is separated into 4 stages:

• Liquids (weeks 1 and 2)
• Puree foods (weeks 3 and 4)
• Soft foods (weeks 5 and 6)
• Regular foods (from week 7 onwards)

The aims of this diet are to:

• Give your stomach time to heal
• Make sure you get enough protein and fluids
• Help you adjust to the small size of your new stomach
• Help you build new eating habits
• Help you lose weight and keep it off
• Protect you from side effects and complications

It is important not to skip any of the stages.

The timings can vary depending on your recovery and how quickly you adjust to the changes in your diet. You may stay in a stage for longer, and this is normal. Do not move on to the next stage until you feel ready.

If you have moved to a new stage too quickly and are having problems, go back to the previous stage and follow it for a few more days.

In the first week, getting enough fluids and protein is very important to help your body heal. All liquids during this stage should be completely smooth, with no bits or lumps.

What to keep in mind

• Drink your liquids at room temperature.
• Take small sips, little and often.
• Increase the amount gradually as you feel comfortable.
• Stop as soon as you feel full. Drinking more than this strains your stomach and can cause pain, nausea or vomiting.
• Aim to drink 1.5 to 2 litres of fluids each day.
• Carry your water bottle with you through the day, so you do not forget to drink.
• Do not lie down for 30 to 45 minutes after drinking. Sit upright or take a short walk, as lying down can make nausea worse.

Your protein supplement is your most important source of nutrition during this stage. Start taking it as soon as possible after surgery, ideally from day 2. Mix 1 sachet a day with water or lactose-free milk and spread it across your meals.

Remember to take the vitamin and mineral supplements recommended by your doctor and dietitian.

Suitable liquids

• Water. You can add a slice of fruit for flavour.
• Tea without sugar
• Decaffeinated coffee
• Homemade chicken, meat or vegetable broth (strained)
• Lactose-free milk or unsweetened plant-based milk (dilute with water if it feels heavy)
• Lactose-free kefir or ayran
• Lactose-free high protein milk
• Diluted unsweetened fruit juice

Do not add spices or sauces when preparing your broth. You can add vegetables for flavour, but remember to strain them out afterwards.

Liquids to avoid

• Fizzy drinks
• Alcohol
• Sugary drinks
• Citrus juices such as orange, lemon and grapefruit juice
• Herbal teas

Sample meal plan

1 glass = around 200ml.

This week, you move on to thicker liquids. Soups are now your main meals. The aim is to prepare your stomach for puree foods.

All of the rules from week 1 still apply this week. You can now have your drinks without diluting them.

Suitable liquids

• Meat, chicken or vegetable soup. Blend the vegetables with the meat or chicken broth until completely smooth.
• Smoothies. Blend lactose-free milk or plant-based milk with low-sugar fruits such as strawberries and green apple. You can add yoghurt or protein powder to increase the protein.
• Lactose-free milk or unsweetened plant-based milk (dilute with water if it feels heavy)
• Lactose-free kefir or ayran
• Lactose-free high protein milk
• Unsweetened fruit juice

Sample meal plan

1 glass = around 200ml.

From the third week onwards, you can start eating puree foods. During this stage, all of your food should have a smooth consistency like yoghurt, with no bits or lumps. You will need to use a blender or food processor to bring your food to a smooth consistency.

Eat 3 meals and 3 snacks each day. Start your meals with small portions and increase the amount slowly as you feel comfortable. Eat slowly and try to take 20 to 30 minutes for each meal. Stop eating as soon as you feel full or uncomfortable.

Choose foods that are high in protein, high in fibre and low in calories. At every meal, eat your protein foods first. Your protein supplement is now your snack.

Suitable foods

• Lean minced meat, chicken, fish
• Eggs
• Cooked cereal
• Cottage cheese
• Yoghurt
• Potato
• Cooked vegetables without skins
• Soft fruits without seeds or skins

Boil, steam, bake or grill your food. Do not fry. If your puree is dry or thick, add some broth, milk or the food’s own juices to soften it.

Sample meal plan

1 glass = around 200ml.

Once you have completed the puree stage, you can move on to soft foods. You no longer need to blend your food. All of your meals should be well cooked and soft enough to mash easily with a fork.

Before moving on to this stage, ask yourself these questions:

• Am I getting enough protein?
• Am I getting enough fluids?
• Can I eat my meals comfortably, without nausea, vomiting or constipation?
• Am I chewing my food well and eating slowly?

If the answer to any of these questions is no, do not rush. Continue with puree foods for a few more days.

Start meat and chicken with mince. If you tolerate it comfortably, you can move on to small diced pieces. If you struggle, go back to mince. Use this stage to build the habit of chewing every mouthful well.

The main focus of your meals and snacks should be protein, so eat your protein foods first at every meal. Between meals, try to have protein rich liquids. Stop eating as soon as you feel full or uncomfortable.

You can gradually switch from lactose-free milk to normal milk. Try to choose skimmed or semi-skimmed milk.

Suitable foods

• Lean minced meat, chicken, fish
• Eggs
• Cottage cheese
• Potato
• Rice, pasta
• Cooked or dried cereal
• Cooked vegetables without skins
• Soft fruits without seeds or skins

Foods to avoid

Avoid foods that are hard, have skins, are difficult to chew or cannot be easily mashed with a fork.

• Raw vegetables (such as celery, asparagus, broccoli)
• Sweetcorn and popcorn
• Nuts and seeds
• Dried fruits
• Hard cheese
• Tough or chewy meats (such as steak)

Sample meal plan

1 glass = around 200ml.

After 6 weeks of the diet, you can gradually start eating regular foods.

Continue to eat 3 meals each day, and try not to leave more than 4 to 5 hours between meals. If you get hungry between meals, choose a nutritious snack such as a piece of fruit, high protein yoghurt or a glass of skimmed milk.

To get used to eating smaller portions, use a side plate for your meals. Fill half of your plate with protein foods, a quarter with vegetables or salad, and a quarter with carbohydrates. Eat your protein first, then your vegetables, and your carbohydrates last. Stop eating before you feel completely full.

Try new foods one at a time. How well you tolerate a food can depend on how you chew, cook and prepare it. If you cannot tolerate a food, wait at least a week and then try it again.

At every stage of the post-operative diet, keep the following in mind:

• Make sure you are getting enough protein.
• Eat your protein foods first at every meal.
• Take small bites, eat slowly and chew well. Take 20 to 30 minutes to complete your meal.
• Stop eating when you feel full or uncomfortable.
• Do not skip meals. Eat regularly, even if you do not feel hungry.
• Do not drink with your meals. Stop drinking 30 minutes before a meal, and wait 30 minutes after a meal before you drink again.
• Aim to drink 1.5 to 2 litres of fluids each day.
• Avoid sweets and sugar.
• Stay away from alcohol and fizzy drinks.
• Stay away from processed and packaged foods.

Every patient’s journey is different. A food that causes no problems for one patient may not agree with you. Others may move on to the next stage earlier, while you need more time. All of this is normal. Do not compare yourself with others, and focus on your own progress.

These rules can feel demanding at times, but each one is there for your health and your long-term success. The more care you take with your diet, the more healthily you lose weight and the better you keep it off.

Remember that if you return to unhealthy eating habits after weight loss surgery, you may not lose all of your excess weight, or you may regain the weight you have lost.

Side effects after surgery are usually caused by not following the post-operative diet correctly. If you eat too much, or eat foods you should not, some side effects can appear. These include:

Constipation

Constipation is usually caused by the sudden change in your diet, a lack of physical activity and a diet low in fibre. If you experience constipation, make sure you are drinking enough fluids, and add fibre-rich foods and probiotics to your diet.

Vomiting

The most common causes of vomiting after surgery are:

• Eating too quickly
• Eating too much
• Not chewing well enough
• Eating foods that are not right for the stage you are in

If you vomit, take a break from eating for a few hours and take small sips of fluids. At your next meals, eat more slowly and make your portions smaller. If the vomiting happens again, go back to the previous stage and follow it for a few days.

Dumping Syndrome

Dumping syndrome happens when too much food passes too quickly from the stomach into the small intestine. It is usually seen after gastric bypass surgery, following foods high in sugar and fat. The most common symptoms are:

• Nausea
• Vomiting
• Diarrhoea
• Sweating
• Dizziness

To protect yourself from dumping syndrome, stay away from sugary and fatty foods, eat slowly and do not drink with your meals.

If any of these side effects applies to you and continues despite following the dietary advice, contact your dietitian or doctor.