Gastric bypass post-op eating plan
Immediately after your surgery you need to allow time for your
internal stitches to heal properly, swelling to settle and also allow
your digestive system to adjust to the new way you will be eating.
It can take 3-6 months for the operation for everything to settle
down totally – some days you will be able to eat foods without any
problem and then, seemingly for no reason, the next day the same food
will make your nauseated. Long term food intolerances are very uncommon.
The size of your stomach pouch and the swelling will initially limit
the amount of food you can eat, but as time goes on you will be able to
eat slightly larger quantities and you need to get to grips with a
healthy eating plan if you are going to get the best results from your
surgery and avoid nutritional side effects.
Whilst individual surgery centres do vary in their specific eating
plan advice, here is general information and guidance for bypass
The first week
You will start taking sips of water the day of your operation and
the following day will probably be able to take free fluids. Once you
are taking fluids easily, we recommend you stay on free fluids for one
week. These include water, tea, coffee (use sweetners rather than
sugar), herb/fruit teas, skimmed milk, low calorie fruit squashes,
fruit juice, consommé, boullion, thin soup, sugar–free jelly.
You can progress to pureed foods in small quantities (4–5 small
meals per day). To start with, make your pureed food very runny (that
will pour off a spoon) such as low fat yogurt (e.g. Muller Light),
custard, soup, mashed potato with gravy, cheese (grated so that it
melts into the potato without lumping), parsley or other sauce for
flavour, stewed apple, tinned fruit (e.g. peaches, pears, apricots – in
juice, not in syrup), Weetabix or ReadyBrek with lots of milk. After
you are tolerating the very sloppy puree for a few days, think about
adding more protein foods such as meat, fish, chicken, beans, lentils
and eggs. All food should be pureed and low in fats and sugars.
- The texture should be like smooth baby food (a
good test is that it should pour off a spoon) and this is most easily
achieved by using a food processor or hand–held blender. You can also
use a potato masher for soft vegetables and potatoes and a sieve and
spoon is also useful to remove lumps and pips. When you puree food,
extra fluid may need to be added to get the smooth consistency. For
savoury foods you might like to use packet or cook–in sauce mixes,
gravy or the cooking water from your vegetables. For fruit and
desserts, fruit juice will loosen the consistency.
- The size of your meals – about 100g, or 5–6
tablespoons is the correct amount. Ensure you eat this slowly and take
small mouthfuls. For the main meal of the day, you might find it easier
to purchase and puree a ready meal such as a Shepherds Pie or Fish Pie
(potato top) and a one–person serving will usually be sufficient for
two meals for you at this stage.
- Stop eating as soon as you start to feel
full. Because your pouch is at the top of your stomach, the feeling of
fullness you will get is different to what you are used to – it is felt
more in your chest than in your stomach. Some people describe it as a
tightness, some as a heaviness.
- Drink 1.5 litres of water (2 1/2 pints) every day. Take it in 100–200ml glassfuls between meals, not with your meals.
Example meals during this stage:
||One Weetabix with milk or|
A tub of yoghurt or fromage frais or
Three tablespoons of porridge or Ready Brek made up
||Smooth soup (about a cupful)or|
||Shepherd's pie or|
Fish pie or
Chicken in white sauce or
Mashed potato and cheese or
Pureed vegetables and mashed potato
|Between meal snacks (once per day)
||Custard with stewed apple or mashed banana or|
Milk pudding (e.g. rice or sago) or
Yoghurt or fromage frais
||Water (not fizzy) or|
Tea, coffee or skimmed milk or
Fruit juice or
Weeks four to six
Continue eating the same sort of food you were for the first four
weeks, but it does not need to be pureed – mashing will make it the
consistency of “toddler food”. It should be still fairly soft though
and keep to the same small quantities and eating 4–5 times per day.
Make sure you chew each small mouthful well.
After the first six weeks
You are now ready to continue on your long term eating plan.
Remember, you are not just eating small amounts to reduce your calorie
intake and lose weight, but you are aiming for a healthy nutritious
eating plan as well. Each individual differs in the foods they can eat,
but there are some golden eating plan rules to follow after a gastric
- Avoid high sugar foods – a high sugar intake will
cause dumping, an extremely unpleasant feeling of nausea, sometimes
accompanied by abdominal pain, diarrhoea and faintness. Because your
bypass alters the normal insulin response mechanism, when you eat sugar
your body will produce an excessive amount of insulin. This can be
considered an advantage of a gastric bypass, creating an in–built
aversion to sugar! If this happens, lie down and stick to fluids until
the feeling has passed and then review your eating patterns and reduce
sugar intake. If you are prescribed liquid formulas of any medicines,
especially antibiotics, please ask you pharmacist to dispense you a
- Eat three meals per day – you should be
satisfied eating three meals a day without getting hungry in between
meals. Beware of developing 'grazing' eating patterns of small snacks
throughout the day.
- Eat healthy, solid food – soft food slips
down easily but you can end up eating more over the course of the day.
Many soft foods are also higher in fat or carbohydrates and as a
consequence you may be taking more calories than you should and your
weight loss will slow down or stop. Choose solid foods without too much
sauce (e.g. small meal of chicken and vegetables with a spoonful of
gravy or sauce) and you will eat less overall and stay full for longer.
- Eat slowly and stop as soon as you feel full
– Most obese people are used to rushing their meals and as there is a
time lag from stretching the wall of your stomach and telling your
brain you are full, you need to be careful with this one or risk pain
or vomiting. Take tiny bites (cut meat up to the size of a pencil–top
rubber) and chew each piece 10–25 times. Once you start to feel full,
- Keep your fluid intake up – Prior to your
surgery you would have obtained a lot of your fluids from your meals,
but with eating smaller quantities you need to increase your liquid
intake. If you have a drink immediately before your meal you may also
find that your stomach is still full and you can't eat your meal. So
initially, avoid fluids half an hour before your meals, and for one
hour afterwards. Calorie laden drinks, including alcohol, will simply
add calories to your daily intake. Women need calcium, and this can be
obtained from skimmed milk and other dairy products, but avoid juice,
squashes and milkshakes. In the first few weeks you may find that fizzy
drinks cause bloating and discomfort too, so these are best avoided.
A healthy diet
There are five main food groups and a healthy diet comprises a mix of them:
- Protein foods – such as meat, fish, eggs, beans – include 2 to 3
60–90g (2–3oz) portions per day. You will have to particularly careful
to chew meat, chicken and fish up thoroughly before you swallow – the
recommended bite size is the size of a pencil–tip eraser.
- Milk and dairy – choose low–fat cheese and limit amount to
30–60g (1–2 oz). Choose skimmed milk and low fat yogurt varieties.
Three portions of dairy food aday will ensure that you are obtaining
sufficient calcium from your diet.
- Fruit and vegetables – try to have 4–5 portions per day. A
small glassful of unsweetened tomato juice counts as one portion.
Salads tend to be easily digested, and green vegetables are also
generally easy to digest.
- Carbohydrates – bread, potatoes and cereals – 2 portions per
day. For many bypass persons, this group is somewhat harder to digest
so you develop an in–built mechanism to reducing your carbohydrate
intake! Replace soft bread in your diet with granary or wholemeal, or
crisp breads which are more easily digestible. One small portion of
60–90g (2–3oz) at each meal will be fine.
- Fats and sugary foods – use a small amount of olive oil for
cooking and replace puddings with a low fat yogurt. As mentioned above,
avoid the calorie–laden foods such as chocolate, sweets or ice cream
which will cause dumping.
Multivitamins after a gastric bypass
It is very important that you take additional vitamins as you are no
longer able to absorb sufficient amounts of them from your food.
Vitamin and mineral deficiency is an avoidable complication after
gastric bypass surgery. Unfortunately, vitamin levels are hard to
detect accurately in the body and you could possibly become deficient
before you start to show signs or symptoms of being so. If you are
unable to afford to buy vitamin tablets, unable to swallow them, or are
vomiting, it is important you speak to your GP or to the bariatric
surgery team to ensure that you receive them in another format so that
you do not become deficient. As always, prevention is much better than
cure. The best source of vitamins and minerals is a healthy diet – for
example, you will get your calcium if you are having three portions of
dairy food in your diet each day (one portion = 1/3 pt milk, a
matchbox-size piece of cheese or 1 pot yogurt).
- One multivitamin tablet every day – choose one that contains
Examples of branded products that are suitable are Centrum Complete A-Z (still available in the non-chewable tablet format), Sanatogen Gold A to Z, Seven Seas Multibionta and Boots Adult Multi-vitamins.
- Vitamins B1 (thiamine) –over 1.4mg
- Vitamin B12 –over 1 μg
- Folacin (folic acid) – over 200 μg
- Additional iron in the form of ferrous sulphate 200mg tablets
twice a day if you are prone to anaemia or if your routine blood tests
show you are becoming anaemic (your GP will tell you).
- Calcium – 800–1,000mg per day if you are not having your
dairy foods as mentioned above – usually taken in the form of a
chewable tablet such as Nature’s Aid.