Gastric Bypass Diet

Having a gastric bypass is really the ultimate step in controlling your food intake. A smaller stomach capacity means that you will feel fuller faster and for longer, therefore be able to reduce your portion sizes and snacking, so that you will lose weight.

However, sensible healthy eating is all the more important with restricted food intake and following some simple rules will ensure that you get great results from your weight loss.

Your gastric bypass diet works in 4 distinct stages:

Pre-operative low calorie diet
Post-operative 0-4 week liquid diet
Post-operative 4-8 week soft diet
Post-operative 8+ week normal diet

You will be provided with The Hospital Group's Patient Information Booklet, which provides comprehensive dietary advice and meal suggestions for each stage of the diet. The information below gives you an idea of what to expect.

Pre-Operative Diet

Following a low fat healthy eating plan before your procedure is essential to reduce the size of your liver in order to help the Surgeon perform the surgery more safely and efficiently. It also enables you to kick start your weight loss and good nutrition will help your recovery post-operatively.

You will have to follow a strict pre-operative diet for approximately 7 days before your surgery. Your Surgeon will specify your pre-operative diet and the duration for which you must follow it. We generally recommend a 1,000-1,200Kcal/day diet and the most common one is a “milk and yoghurt” diet, which is based on milk and fluids only to effectively reduce the size of the liver and ensure good protein consumption.

Sample Pre-Operative Diet

7am All milk coffee (250ml)
9am Glass of milk (250ml)
12noon Diet yoghurt and cup of tea with milk
3pm Diet yoghurt
5pm Oxo drink
7pm All milk coffee (250ml)
9pm Vanilla flavoured milk (250ml)

Post-Operative 0-4 Week Diet

You will only be allowed fluids for the first 4 weeks following your operation. This will ensure optimum healing from the surgical procedure.

As you will be only consuming fluids it is essential you follow all the guidelines. They are designed to provide you with a balanced intake of energy, protein and other nutrients, to ensure you have a good recovery, kick start your weight loss & boost general well-being.

Sample 0-4 Week Diet

Breakfast - Slimfast, Ultra Life or Clinikcal shake to provide 200-250 kcals
Snack 1 - Smoothie
Lunch - nutritional hearty soup pureed into liquid
Snack 2 - Cup a Soup
Evening meal - pureed nutritional hearty soup with added milk
7pm - milky coffee
9pm - vanilla milk

4-8 weeks Post Surgery - Soft Food

You will now be ready to start a “soft diet”. This means that you can introduce normal foods, but aim for the consistency of cottage pie/ well cooked cauliflower cheese/scrambled egg - foods easily broken with a fork.

You must avoid all crunchy foods such as potato skins or salads at this stage while you are still healing from the procedure.

Sample 4-8 week diet

Breakfast - Weetabix with semi-skimmed milk
Snack 1 - yoghurt
Lunch - soft pasta with tomato sauce
Snack 2 - thick fruit smoothie
Evening meal - lean minced meat and blended casserole, mashed banana and low fat custard
7pm - milky coffee

Always ensure a good protein portion at each meal - as a guide this should be the size of the palm of your hand.

Serve your meals on a tea plate to manage the portion size and drink plenty of fluids throughout the day. However, do not drink with your meal and allow at least 1 hour after a meal.

8 weeks and onwards

Once you have reached this stage you will be able to resume ‘normal eating’ i.e. all textures of food. You will have been seen by the dietitian or will have been sent an appointment to be seen in the near future. You will then be followed up by the dietitian on a regular basis who will monitor your progress, help, support and guide you towards eating a healthier diet for life.

At this stage you will be used to consuming smaller amounts than you did prior to the procedure, but can move onto a normal post-operative diet.

You will be given a series of guidelines, including:

Aim for small portions. Your stomach pouch has a smaller capacity which should not be stretched. Try using a child’s plate or a tea plate to control portion size
If you feel hungry and your appetite is increasing this may indicate that you may be ready for a band fill
Drink plenty before a meal and leave at least one hour before your next drink
Eat very slowly & chew you food well - aim to chew 20 times per mouthful!
Continue to avoid fizzy drinks
Imagine a plate divided into 3 - one third should be protein, one third carbohydrate and the last third of the plate vegetables
Continue to take your multivitamin/mineral + calcium supplement - this is for life
You may find certain foods difficult to tolerate e.g. nuts, pips, seeds, acidic foods such as citrus fruits etc - be careful & avoid if you find these cause a problem
Use skimmed milk as it contains fewer calories
Do not lie down immediately after a meal
Reduce the amount of cheese you consume – try cream cheese, cottage cheese or cheese spread and always choose low fat
If you suffer from wind you may want to avoid onions, cauliflower and broccoli
You may find certain foods difficult to tolerate e.g. nuts, pips, seeds, acidic foods such as citrus fruits etc - be careful & avoid IF you find these cause a problem
Continue to avoid bread, rice, meat and chicken (minced meat is allowed) for the first 3 months post op – until you are comfortable with your new way of eating
Take all fat/skin off meat before cooking
Avoid too much sauce/gravy - opt for hard/dry & ‘crunchy’ foods
Limit the amount of treats – chocolates, crisps, biscuits, cakes, desserts etc. These will not only slip down easily, but will also add empty calories
If you are cooking with oil, choose olive or rapeseed oil and use sparingly as they still contain as many calories as other types of oil – try a spray oil instead.

Food Diary

Our dietitians ask all patients to keep a food diary to record their food and liquid intake, exercise and any comments. This is reviewed on a regular basis to help you get the greatest benefit from your treatment. Any bariatric procedure is a tool, or a starting point for your weight loss journey - you do the work in terms of managing your diet, but the bariatric procedure will help enormously.

Vitamins and Supplements

It’s also important to note that as well as reduced absorption of calories, a gastric bypass may also reduce absorption of important vitamins and minerals such as iron, vitamin B-12 and calcium. Deficiencies in these nutrients can lead to problems such as iron deficiency or osteoporosis.

This is why patients undergoing gastric bypass are recommended to take a daily vitamin and mineral supplement.

It is essential you take a multivitamin/mineral and a calcium supplement long term. You may find a chewable option more tolerable; alternatively break the tablet in half. We recommend Centrum Chewable, Sanatogen Gold or Multibionta & Calcichew or Sevenseas Calcium Chewable. Some own brand products are also suitable just make sure they contain vitamins and minerals.

"Dumping syndrome”

Dumping syndrome is a particular problem that can occur after gastric bypass surgery.

Early Dumping Syndrome occurs <30minutes after eating and is caused by food passing too quickly from the stomach into the small intestine. As the food is more concentrated than the fluid in the gut, water is drawn into the gut for dilution. This then leads to a drop in blood pressure making you feel dizzy and faint.
Late Dumping Syndrome can occur 2-3 hours after eating. This is triggered by a rise in blood sugars following food. The body releases insulin to normalise sugar levels; however the amount produced may overcompensate leading to a low blood sugar level. This can make you feel faint, weak, dizzy, sweaty etc

If you experience Dumping Syndrome, sit down and drink plenty of water. For Late Dumping Syndrome, eating a sweet will help ease the symptoms. This must be followed up with a small snack low in sugar e.g. crackers, yoghurt etc, otherwise the dumping syndrome will be triggered off again following the sweet!

You can reduce dumping syndrome by following the guidelines set out in this information leaflet.

The key points are:

eat slowly
reduce the amount of sugary foods eaten
eat small regular meals
increase the fibre content of your meals e.g. high fibre cereals, fruit, vegetables etc.
avoid drinking with meals