13 January 2021

Section 10: Bowel habits and bowel health

Bowel Health

To maintain optimal bowel health, adults are recommended to aim for 30g of fibre per day. Among many other health benefits, fibre is essential in managing both constipation and diarrhoea and it has been shown to reduce the risk of developing bowel cancer. The best way to ensure that you are getting a variety of fibre in your diet and meeting your needs is by choosing foods which are rich sources: such as wholegrain cereals, granary bread, pulses, fruits and vegetables.

In general, it is normal to move our bowels as frequently as three times as day and as infrequently as three times per week. However, after undergoing bariatric surgery this may change and you may move your bowels more or less frequently than before. As a rule of thumb, if after surgery you have to move your bowels more often than three times per day or less often than every three days, and if the consistency is too loose or too uncomfortable to pass, and you have tried the common remedies described below, speak to a healthcare professional.

You should never see blood when opening your bowels. If you do, call your GP without delay.

A healthy bowel motion would resemble Type 3 or 4 on the Bristol Stool chart.     


There will be a reduction in the volume of your stools immediately after surgery, which is caused by a decrease in food volume, ingesting less fibre during the fluid/pureed phase and/or consuming insufficient fluid. The main method of prevention is to drink sufficient amounts of fluid.

The following general principles will help you to restore a normal bowel pattern after surgery:

  1. Drink plenty of fluids. This does not have to be just water – include sugar free/no added sugar flavoured water, tea/coffee, herbal/fruit teas, sugar free/no added sugar squash.
  2. Exercise regularly in accordance with the guidelines in Physical Activity.
  3. Include prunes or unsweetened prune juice in your diet daily.
  4. Start eating high fibre foods, e.g. high fibre crackers (e.g. Ryvita, Finncrisp), cereals, potato skins, wholewheat pasta, bulgur wheat as soon as you progress back onto textured/solid foods 4 weeks post-op (see Dietary Advice for week 5 onwards). During the soft food stage (see Dietary Advice for weeks 3 & 4), you can include soft high-fibre foods such as Weetabix, porridge, lentils and mashed beans.
  5. Include fruit and vegetables in your diet every day.

If constipation persists, you may need to try taking a natural laxative such as Senna.  If this is ineffective, see your GP for a prescription of lactulose, but it is best if you contact us to speak with a dietitian or nurse in the first instance.


Diarrhoea can be a problem after any gastric surgery, and can be caused by the movement of your digestive tract being upset. It can also be due to lactose intolerance, so if you are drinking a lot of milk or meal replacements, reduce and switch to hearty soups instead (see under “Nausea” above). Choosing bland foods can help and it is crucial you are drinking sufficient fluid. Loperamide (e.g. Imodium) can also be used.


Wind pain, initially post-surgery, is discussed in Recovery. Further down the line, wind only usually occurs due to poor eating technique. Make sure you are following the ‘20, 20, 20, 20 rule’, and the remedies described earlier can still be effective i.e. peppermint tea, gripe water, Deflatine/Wind-eze.



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